# caver.contract
`caver.contract` 객체는 Klaytn 블록체인과 스마트 컨트랙트 간의 상호작용을 쉽게 만들어 줍니다. 새 컨트랙트 객체를 생성할 때 해당 스마트 컨트랙트를 위해 JSON 인터페이스를 제공해야 하는데, 이때 caver-js가 자바스크립트로 작성된 컨트랙트 객체와의 모든 호출을 RPC를 통해 하위 수준의 ABI 호출로 자동 변환시켜줍니다.
이를 통해 스마트 컨트랙트가 마치 자바스크립트 객체인 것처럼 스마트 컨트랙트와 상호작용할 수 있습니다.
## caver.contract.create
```javascript
caver.contract.create(jsonInterface [, address] [, options])
```
JSON 인터페이스 오브젝트에 정의된 모든 메소드 및 이벤트로 새 컨트랙트 인스턴스를 생성합니다. This function works the same as [new caver.contract](#new-contract).
**참고** `caver.contract.create`는 caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1)부터 지원됩니다.
**Parameters**
See the [new caver.contract](#new-contract).
**Return Value**
See the [new caver.contract](#new-contract).
**Example**
```javascript
const contract = caver.contract.create([
{
constant: true,
inputs: [{ name: 'interfaceId', type: 'bytes4' }],
name: 'supportsInterface',
outputs: [{ name: '', type: 'bool' }],
payable: false,
stateMutability: 'view',
type: 'function',
},
...
], '0x{address in hex}')
```
## caver.contract
```javascript
new caver.contract(jsonInterface [, address] [, options])
```
Creates a new contract instance with all its methods and events defined in its JSON interface object.
**Parameters**
| Name | Type | Description |
| ------------- | ------ | ----------------------------------------------------------------------------------------- |
| jsonInterface | object | 컨트랙트를 인스턴스화하기 위한 JSON 인터페이스 |
| address | string | (선택 사항) 호출할 스마트 컨트랙트의 주소. `myContract.options.address = '0x1234..'`를 사용하여 나중에 추가할 수 있습니다. |
| options | object | (선택 사항) 컨트랙트 옵션. 자세한 내용은 아래 표를 참조하세요. |
옵션 개체에는 다음이 포함됩니다:
| Name | Type | Description |
| ------------- | ------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| from | string | (선택 사항) 트랜잭션이 만들어진 송신자 주소. |
| gasPrice | string | (선택 사항) 트랜잭션에 사용할 peb 단위의 가스 가격. |
| gas | number | (선택 사항) 트랜잭션에 규정된 최대 가스 (가스 제한). |
| data | string | (선택 사항) 컨트랙트의 바이트 코드. 컨트랙트가 배포될 때 사용됩니다. |
| feeDelegation | boolean | (선택 사항) 수수료 위임 트랜잭션 사용 여부를 나타냅니다. |
| feePayer | string | (선택 사항) 트랜잭션 수수료를 부담하는 수수료 납부자의 주소입니다. `feeDelegation`이 `true`일 때, 값은 트랜잭션의 `feePayer` 필드에 설정됩니다. |
| feeRatio | string | (optional) Fee payer가 부담하게될 트랜잭션 수수료의 비율입니다. `feeDelegation`이 `true`이며, `feeRatio`가 유효한 값으로 설정되었을 경우, 부분 수수료 위임 트랜잭션이 사용됩니다. 유효한 범위는 1에서 99 사이입니다. 0이나 100 이상의 값은 허용되지 않습니다. |
**Return Value**
| Type | Description |
| ------ | -------------------------- |
| object | 모든 메소드와 이벤트가 있는 컨트랙트 인스턴스. |
**Example**
```javascript
const myContract = new caver.contract([...], '0x{address in hex}', { gasPrice: '25000000000' })
```
## myContract.options
```javascript
myContract.options
```
컨트랙트 인스턴스에 대한 `options` 객체. `from`, `gas`, `gasPrice`, `feePayer` 그리고 `feeRatio`는 트랜잭션 전송시 대체값으로 사용됩니다.
**속성**
| Name | Type | Description |
| ------------- | ------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| address | string | 컨트랙트가 배포된 주소. |
| jsonInterface | Array | The JSON interface of the contract. |
| from | string | 컨트랙트 배포/실행 트랜잭션을 전송하는 기본 주소입니다. 트랜잭션 생성시 `from` 주소가 정의되어 있지 않다면, 트랜잭션 생성시 항상 `myContract.options.from`가 사용됩니다. |
| gasPrice | string | 트랜잭션에 사용할 peb 단위의 가스 가격. |
| gas | number | 트랜잭션에 제공된 최대 가스 (가스 제한). |
| data | string | 컨트랙트의 바이트 코드. Used when the contract gets deployed. |
| feeDelegation | boolean | (optional) Whether to use fee delegation transaction. |
| feePayer | string | (optional) The address of the fee payer paying the transaction fee. When `feeDelegation` is `true`, the value is set to the `feePayer` field in the transaction. |
| feeRatio | string | (optional) The ratio of the transaction fee the fee payer will be burdened with. If `feeDelegation` is `true` and `feeRatio` is set to a valid value, a partial fee delegation transaction is used. The valid range of this is between 1 and 99. The ratio of 0, or 100 and above are not allowed. |
**참고** `feeDelegation`, `feePayer`, 그리고 `feeRatio`는 caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1) 이후부터 지원됩니다.
**Example**
```javascript
> myContract.options
{
address: [Getter/Setter],
jsonInterface: [Getter/Setter],
from: [Getter/Setter],
feePayer: [Getter/Setter],
feeDelegation: [Getter/Setter],
feeRatio: [Getter/Setter],
gasPrice: [Getter/Setter],
gas: [Getter/Setter],
data: [Getter/Setter]
}
> myContract.options.from = '0x1234567890123456789012345678901234567891' // default from address
> myContract.options.gasPrice = '25000000000000' // default gas price in peb
> myContract.options.gas = 5000000 // provide as fallback always 5M gas
> myContract.options.feeDelegation = true // use fee delegation transaction
> myContract.options.feePayer = '0x1234567890123456789012345678901234567891' // default fee payer address
> myContract.options.feeRatio = 20 // default fee ratio when send partial fee delegation transaction
```
## myContract.options.address
```javascript
myContract.options.address
```
이 컨트랙트 인스턴스 `myContract`에 사용된 주소. 해당 컨트랙트에서 caver-js에 의해 생성된 모든 트랜잭션에 이 주소가 `to`로서 포함될 것입니다.
**속성**
| Name | Type | Description |
| ------- | --------- | ----------- |
| address | string \\ | `null` |
**Example**
```javascript
> myContract.options.address
'0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae'
// 컨트랙트 주소 설정
> myContract.options.address = '0x1234FFDD...'
```
## myContract.options.jsonInterface
```javascript
myContract.options.jsonInterface
```
이 컨트랙트 `myContract`의 ABI에서 파생된 JSON 인터페이스 객체.
**Property**
| Name | Type | Description |
| ------------- | ----- | ---------------------------------------------------------- |
| jsonInterface | Array | 이 컨트랙트의 JSON 인터페이스. 이를 재설정하면 컨트랙트 인스턴스의 메소드 및 이벤트가 재생성됩니다. |
**Example**
```javascript
> myContract.options.jsonInterface
[
{
constant: true,
inputs: [ { name: 'interfaceId', type: 'bytes4' } ],
name: 'supportsInterface',
outputs: [ { name: '', type: 'bool' } ],
payable: false,
stateMutability: 'view',
type: 'function',
signature: '0x01ffc9a7',
},
...
{
anonymous: false,
inputs: [
{ indexed: true, name: 'owner', type: 'address' },
{ indexed: true, name: 'spender', type: 'address' },
{ indexed: false, name: 'value', type: 'uint256' }
],
name: 'Approval',
type: 'event',
signature: '0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925',
},
]
// 새 jsonInterface 설정
> myContract.options.jsonInterface = [...]
```
## myContract.clone
```javascript
myContract.clone([contractAddress])
```
현재 컨트랙트 인스턴스를 복제합니다.
**Parameters**
| Name | Type | Description |
| --------------- | ------ | ---------------------------------------------------------------------------------- |
| contractAddress | String | (선택 사항) 새 컨트랙트의 주소입니다. 미입력시 오리지널 인스턴스(예: `myContract.options.address`)의 주소로 설정됩니다. |
**Return Value**
| Type | Description |
| ------ | ----------------- |
| object | 새로 복제된 컨트랙트 인스턴스. |
**Example**
```javascript
> myContract.clone()
Contract {
currentProvider: [Getter/Setter],
...
_keyrings: KeyringContainer { ... }
}
```
## myContract.deploy
```javascript
myContract.deploy(options, byteCode [, param1 [, param2 [, ...]]])
```
컨트랙트를 Klaytn 네트워크에 배포합니다. 성공적으로 배포된 후, Promise는 새로운 컨트랙트 인스턴스와 함께 해결(resolved)될 것입니다. Unlike the usability of the existing [myContract.deploy](#mycontract-deploy) function, this function sends a transaction directly to the Klaytn network. 반환된 객체와 함께 `send()`를 호출할 필요가 없습니다.
**NOTE** 서명을 하기 위해서는 `caver.wallet`가 `options`나 `myContract.options`의 `from`와 `feePayer`에 해당하는 키링 인스턴스를 포함해야 합니다.
**참고** `myContract.deploy`는 caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1)부터 지원됩니다.
**Parameters**
| Name | Type | Description |
| ---------- | ------ | -------------------------------------------------------------------------------------------------- |
| options | object | 전송에 사용되는 옵션. See the table in [methods.methodName.send](#methods-methodname-send) for the details. |
| byteCode | string | The byte code of the contract. |
| parameters | Mixed | (선택 사항) 배포시 생성자에게 전달되는 파라미터입니다. |
**Return Value**
`Promise`는 `PromiEvent`를 반환: Promise가 새로운 컨트랙트 인스턴스와 함께 해결(resolved)됩니다.
| Type | Description |
| ---------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| PromiEvent | 프로미스(promise)가 조합된 이벤트 이미터(event emitter). 트랜잭션 영수증이 준비되면 해결(resolve)됩니다. `myContract.deploy()`에서 `send()`가 호출될 경우, Promise는 새로운 컨트랙트 인스턴스와 함께 해결(resolved)됩니다. |
PromiEvent에서는 다음 이벤트가 발생할 수 있습니다.
* `"transactionHash"`: 트랜잭션이 전송되고 트랜잭션 해시가 준비된 직후에 발생합니다. 타입은 `string`입니다.
* `receipt`: 트랜잭션 영수중이 준비되면 발생합니다. See [caver.rpc.klay.getTransactionReceipt](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.rpc/klay#caver-rpc-klay-gettransactionreceipt) for more details. 타입은 `object`입니다.
* `error`: 전송 중 에러가 발생하면 발생합니다. 가스 부족 에러(out-of-gas)가 발생한 경우 두 번째 인자는 트랜잭션 영수증입니다. 타입은 `error`입니다.
**Example**
```javascript
// Deploy a smart contract without constructor arguments
> myContract.deploy({
from: '0x{address in hex}',
gas: 1500000,
}, '0x{byte code}')
.on('error', function(error) { ... })
.on('transactionHash', function(transactionHash) { ... })
.on('receipt', function(receipt) {
console.log(receipt.contractAddress) // contains the new contract address
})
.then(function(newContractInstance) {
console.log(newContractInstance.options.address) // instance with the new contract address
})
// Deploy a smart contract with constructor arguments
> myContract.deploy({
from: '0x{address in hex}',
gas: 1500000,
}, '0x{byte code}', 'keyString', ...)
.on('error', function(error) { ... })
.on('transactionHash', function(transactionHash) { ... })
.on('receipt', function(receipt) {
console.log(receipt.contractAddress)
})
.then(function(newContractInstance) {
console.log(newContractInstance.options.address)
})
// Deploy a smart contract with fee delegation transaction (TxTypeFeeDelegatedSmartContractDeploy)
> myContract.deploy({
from: '0x{address in hex}',
feeDelegation: true,
feePayer: '0x{address in hex}',
gas: 1500000,
}, '0x{byte code}')
.on('error', function(error) { ... })
.on('transactionHash', function(transactionHash) { ... })
.on('receipt', function(receipt) {
console.log(receipt.contractAddress)
})
.then(function(newContractInstance) {
console.log(newContractInstance.options.address)
})
// Deploy a smart contract with partial fee delegation transaction (TxTypeFeeDelegatedSmartContractDeployWithRatio)
> myContract.deploy({
from: '0x{address in hex}',
feeDelegation: true,
feePayer: '0x{address in hex}',
feeRatio: 30,
gas: 1500000,
}, '0x{byte code}')
.on('error', function(error) { ... })
.on('transactionHash', function(transactionHash) { ... })
.on('receipt', function(receipt) {
console.log(receipt.contractAddress)
})
.then(function(newContractInstance) {
console.log(newContractInstance.options.address)
})
```
## myContract.deploy
```javascript
myContract.deploy(options)
```
Klaytn에 스마트 컨트랙트를 배포할 때 사용되는 객체를 반환합니다. `myContract.deploy({ data, arguments }).send(options)`를 호출함으로써 스마트 컨트랙트 배포 트랜잭션을 전송할 수 있습니다. After a successful deployment, the promise will be resolved with a new contract instance.
**Parameters**
| Name | Type | Description |
| ------- | ------ | --------------------------------------- |
| options | object | 배포에 사용되는 옵션 객체입니다. 자세한 내용은 아래 표를 참조하세요. |
옵션 개체에는 다음이 포함됩니다:
| Name | Type | Description |
| --------- | ------ | ------------------------------ |
| data | string | The byte code of the contract. |
| arguments | Array | (선택 사항) 배포시 생성자에게 전달되는 인자입니다. |
**Return Value**
| Type | Description |
| ------ | ------------------------------------------------------------------------------------------------------------------------------ |
| object | An object in which arguments and functions for contract distribution are defined. See the below table to find the description. |
The object contains the following:
| Name | Type | Description |
| ---------------------------------------------------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| arguments | Array | The arguments passed in `options.arguments`. |
| [send](#methods-methodname-send) | function | The function that will deploy the contract to the Klaytn. The promise as the result of this function will be resolved with the new contract instance. |
| [sign](#methods-methodname-sign) | function | The function that will sign a smart contract deploy transaction as a sender. The sign function will return signed transaction. |
| [signAsFeePayer](#methods-methodname-signasfeepayer) | function | The function that will sign a smart contract deploy transaction as a fee payer. The signAsFeePayer function will return signed transaction. |
| [estimateGas](#methods-methodname-estimategas) | function | The function that will estimate the gas used for the deployment. The execution of this function does not deploy the contract. |
| [encodeABI](#methods-methodname-encodeabi) | function | The function that encodes the ABI of the deployment, which is contract data + constructor parameters. The execution of this function does not deploy the contract. |
**참고** `myContract.deploy({ data, arguments }).sign(options)` and `myContract.deploy({ data, arguments }).signAsFeePayer(options)`는 caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1)부터 지원됩니다.
**Example**
```javascript
> myContract.deploy({
data: '0x12345...',
arguments: [123, 'My string']
})
.send({
from: '0x1234567890123456789012345678901234567891',
gas: 1500000,
value: 0,
}, function(error, transactionHash) { ... })
.on('error', function(error) { ... })
.on('transactionHash', function(transactionHash) { ... })
.on('receipt', function(receipt) {
console.log(receipt.contractAddress) // contains the new contract address
})
.then(function(newContractInstance) {
console.log(newContractInstance.options.address) // instance with the new contract address
})
// When the data is already set as an option to the contract itself
> myContract.options.data = '0x12345...'
> myContract.deploy({
arguments: [123, 'My string']
})
.send({
from: '0x1234567890123456789012345678901234567891',
gas: 1500000,
value: 0,
})
.then(function(newContractInstance) {
console.log(newContractInstance.options.address) // instance with the new contract address
})
// Simply encoding
> myContract.deploy({
data: '0x12345...',
arguments: [123, 'My string']
})
.encodeABI()
'0x12345...0000012345678765432'
// Gas estimation
> myContract.deploy({
data: '0x12345...',
arguments: [123, 'My string']
})
.estimateGas(function(err, gas) {
console.log(gas)
})
```
## myContract.send
```javascript
myContract.send(options, methodName [, param1 [, param2 [, ...]]])
```
스마트 컨트랙트 함수를 실행하기 위한 트랜잭션을 보냅니다. 이러한 호출은 스마트 컨트랙트의 상태를 변경할 수 있습니다.
이 함수에 사용되는 트랜잭션 타입은 `options`나 `myContract.options`에 정의된 값에 따라 결정됩니다. `myContract.send`를 통해 수수료 위임 트랜잭션을 사용하고 싶다면, `feeDelegation`와 `feePayer`를 올바르게 설정해야 합니다.
* `feeDelegation` is not defined or defined to `false`: [SmartContractExecution](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/basic#smartcontractexecution)
* `feeDelegation`가 `true`로 정의되었지만, `feePayer`가 정의되지 않음: 에러 반환.
* `feeDelegation` is defined to `true` and `feePayer` is defined, but `feeRatio` is not defined: [FeeDelegatedSmartContractExecution](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractexecution)
* `feeDelegation` is defined to `true` and `feePayer` and `feeRatio` are defined: [FeeDelegatedSmartContractExecutionWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractexecutionwithratio)
**NOTE** `caver.wallet` must contains keyring instances corresponding to `from` and `feePayer` in `options` or `myContract.options` to make signatures.
**참고** `myContract.send`는 caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1)부터 지원됩니다.
**Parameters**
| Name | Type | Description |
| ---------- | ------ | ------------------------------------------------------------------------------------------------------------------- |
| options | object | The options used for sending. See the table in [methods.methodName.send](#methods-methodname-send) for the details. |
| methodName | string | 실행할 컨트랙트 함수의 메서드 이름입니다. |
| parameters | Mixed | (선택 사항) 스마트 컨트랙트 함수에 전달되는 파라미터입니다. |
**Return Value**
`Promise` returns `PromiEvent`
| Type | Description |
| ---------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| PromiEvent | A promise combined event emitter. It will be resolved when the transaction receipt is available. The promise will be resolved with the new contract instance. |
For PromiEvent, the following events are available:
* `"transactionHash"`: 트랜잭션이 전송되고 트랜잭션 해시가 준비된 직후에 발생합니다. Its type is `string`.
* `receipt`: It is fired when the transaction receipt is available. See [caver.rpc.klay.getTransactionReceipt](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.rpc/klay#caver-rpc-klay-gettransactionreceipt) for more details. Its type is `object`.
* `error`: It is fired if an error occurs during sending. On an out-of-gas error, the second parameter is the receipt. Its type is `Error`.
**Example**
```javascript
// Send a SmartContractExecution and use the promise
> myContract.send({ from: '0x{address in hex}', gas: 1000000 }, 'methodName', 123).then(console.log)
{
blockHash: '0x294202dcd1d3c422880e2a209b9cd70ce7036300536c78ab74130c5717cb90da',
blockNumber: 16342,
contractAddress: null,
from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
gas: '0xf4240',
gasPrice: '0x5d21dba00',
gasUsed: 47411,
input: '0x983b2...',
logsBloom: '0x00800...',
nonce: '0x1cd',
senderTxHash: '0xe3f50d2bab2c462ef99379860d2b634d85a0c9fba4e2b189daf1d96bd4bbf8ff',
signatures: [ { V: '0x4e43', R: '0x2ba27...', S: '0x50d37...' } ],
status: true,
to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
transactionHash: '0xe3f50d2bab2c462ef99379860d2b634d85a0c9fba4e2b189daf1d96bd4bbf8ff',
transactionIndex: 0,
type: 'TxTypeSmartContractExecution',
typeInt: 48,
value: '0x0',
events: {...}
}
// Send a SmartContractExecution and use the event emitter
> myContract.send({ from: '0x{address in hex}', gas: 1000000 }, 'methodName', 123)
.on('transactionHash', function(hash) {
...
})
.on('receipt', function(receipt) {
console.log(receipt)
})
.on('error', console.error)
// Send a FeeDelegatedSmartContractExecution
> myContract.send({
from: '0x{address in hex}',
gas: 1000000,
feeDelegation: true,
feePayer: '0x{address in hex}',
}, 'methodName', 123).then(console.log)
{
blockHash: '0x149e36f279577c306fccb9779a0274e802501c32f7054c951f592778bd5c168a',
blockNumber: 16458,
contractAddress: null,
feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
feePayerSignatures: [ { V: '0x4e43', R: '0x48c28...', S: '0x18413...' } ],
from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
gas: '0xf4240',
gasPrice: '0x5d21dba00',
gasUsed: 57411,
input: '0x983b2d5600000000000000000000000022bb89bd35e7b12bd25bea4165cf0f9330032f8c',
logsBloom: '0x00800...',
nonce: '0x1f5',
senderTxHash: '0x5b06ca5046229e066c11dfc0c74fcbc98509294370981f9b142378a8f2bd5fe8',
signatures: [ { V: '0x4e44', R: '0xfb707...', S: '0x641c6...' } ],
status: true,
to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
transactionHash: '0x0e04be479ad06ec87acbf49abd44f16a56390c736f0a7354860ebc7fc0f92e13',
transactionIndex: 1,
type: 'TxTypeFeeDelegatedSmartContractExecution',
typeInt: 49,
value: '0x0',
events: {...}
}
// Send a FeeDelegatedSmartContractExecutionWithRatio
> myContract.send({
from: '0x{address in hex}',
gas: 1000000,
feeDelegation: true,
feePayer: '0x{address in hex}',
feeRatio: 30,
}, 'methodName', 123).then(console.log)
{
blockHash: '0x8f0a0137cf7e0fea503c818910140246437db36121871bc54b2ebc688873b3f3',
blockNumber: 16539,
contractAddress: null,
feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
feePayerSignatures: [ { V: '0x4e43', R: '0x80db0...', S: '0xf8c7c...' } ],
feeRatio: '0x1e',
from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
gas: '0xf4240',
gasPrice: '0x5d21dba00',
gasUsed: 62411,
input: '0x983b2d560000000000000000000000007ad1a538041fa3ba1a721f87203cb1a3822b8eaa',
logsBloom: '0x00800...',
nonce: '0x219',
senderTxHash: '0x14c7b674a0e253b31c85c7be8cbfe4bf9d86e66e940fcae34b854e25eab1ce15',
signatures: [ { V: '0x4e43', R: '0xd57ef...', S: '0xe14f3...' } ],
status: true,
to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
transactionHash: '0xfbf00ec189aeb0941d554384f1660ffdac7768b3af2bb1526bcb3983215c1183',
transactionIndex: 0,
type: 'TxTypeFeeDelegatedSmartContractExecutionWithRatio',
typeInt: 50,
value: '0x0',
events: {...}
}
```
## myContract.sign
```javascript
myContract.sign(options, methodName [, param1 [, param2 [, ...]]])
```
스마트 컨트랙트 배포 또는 스마트 컨트랙트 함수 실행을 위해 발신자로서 스마트 컨트랙트 트랜잭션에 서명합니다.
스마트 컨트랙트가 배포되었다면 `myContract.sign({ from, ... }, 'constructor', byteCode, ...)`와 같이 'constructor'를 methodName에 입력할 수 있습니다.
The transaction type used for this function depends on the `options` or the value defined in `myContract.options`. `myContract.sign`를 통해 수수료 위임 트랜잭션을 사용하고 싶다면, `feeDelegation`dl `true`로 정의되어야 합니다.
* `feeDelegation` is not defined or defined to `false`: [SmartContractDeploy](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/basic#smartcontractdeploy) / [SmartContractExecution](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/basic#smartcontractexecution)
* `feeDelegation` is defined to `true`, but `feeRatio` is not defined: [FeeDelegatedSmartContractDeploy](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractdeploy) / [FeeDelegatedSmartContractExecution](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractexecution)
* `feeDelegation` is defined to `true` and `feeRatio` is defined: [FeeDelegatedSmartContractDeployWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractdeploywithratio) / [FeeDelegatedSmartContractExecutionWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractexecutionwithratio)
**NOTE** 서명을 하기 위해서는 `caver.wallet`가 `options`나 `myContract.options`의 `from`에 해당하는 키링 인스턴스를 포함해야 합니다.
**참고** `myContract.sign`은 caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1)부터 지원됩니다.
**Parameters**
| Name | Type | Description |
| ---------- | ------ | ---------------------------------------------------------------------------------------------------------------------------- |
| options | object | The options used for sending. See the table in [methods.methodName.send](#methods-methodname-send) for the details. |
| methodName | string | The method name of the contract function to execute. 스마트 컨트랙트 배포를 위해 트랜잭션에 서명하고 싶다면 메서드 이름 대신 'constructor' 문자열을 사용하세요. |
| parameters | Mixed | (optional) The parameters that get passed to the smart contract function. 스마트 컨트랙트 배포 트랜잭션에 서명하고 싶다면 바이트코드와 생성자 파라미터를 전달하세요. |
**Return Value**
`Promise` returning [Transaction](https://github.com/klaytn/klaytn-docs-ko/blob/main/docs/dapp/sdk/caver-js/api-references/caver.transaction) - The signed smart contract transaction.
**Example**
```javascript
// Sign a SmartContractDeploy
> myContract.sign({ from: '0x{address in hex}', gas: 1000000 }, 'constructor', byteCode, 123).then(console.log)
SmartContractDeploy {
_type: 'TxTypeSmartContractDeploy',
_from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x4e43', _r: '0xeb6b5...', _s: '0x5e4f9...' } ],
_to: '0x',
_value: '0x0',
_input: '0x60806...',
_humanReadable: false,
_codeFormat: '0x0',
_chainId: '0x2710',
_gasPrice: '0x5d21dba00',
_nonce: '0x2a5'
}
// Sign a FeeDelegatedSmartContractDeploy
> myContract.sign({ from: '0x{address in hex}', feeDelegation: true, gas: 1000000 }, 'constructor', byteCode, 123).then(console.log)
FeeDelegatedSmartContractDeploy {
_type: 'TxTypeFeeDelegatedSmartContractDeploy',
_from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x4e43', _r: '0xee0f5...', _s: '0x31cbf...' } ],
_feePayer: '0x0000000000000000000000000000000000000000',
_feePayerSignatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_to: '0x',
_value: '0x0',
_input: '0x60806...',
_humanReadable: false,
_codeFormat: '0x0',
_chainId: '0x2710',
_gasPrice: '0x5d21dba00',
_nonce: '0x320'
}
// Sign a FeeDelegatedSmartContractDeployWithRatio
> myContract.sign({ from: keyring.address, feeDelegation: true, feeRatio: 30, gas: 1000000 }, 'constructor', byteCode, 123).then(console.log)
FeeDelegatedSmartContractDeployWithRatio {
_type: 'TxTypeFeeDelegatedSmartContractDeployWithRatio',
_from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x4e44', _r: '0x4c2b0...', _s: '0x47df8...' } ],
_feePayer: '0x0000000000000000000000000000000000000000',
_feePayerSignatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_feeRatio: '0x1e',
_to: '0x',
_value: '0x0',
_input: '0x60806...',
_humanReadable: false,
_codeFormat: '0x0',
_chainId: '0x2710',
_gasPrice: '0x5d21dba00',
_nonce: '0x306'
}
// Sign a SmartContractExecution
> myContract.sign({ from: '0x{address in hex}', gas: 1000000 }, 'methodName', 123).then(console.log)
SmartContractExecution {
_type: 'TxTypeSmartContractExecution',
_from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x4e44', _r: '0xb2846...', _s: '0x422c1...' } ],
_to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
_value: '0x0',
_input: '0x983b2...',
_chainId: '0x2710',
_gasPrice: '0x5d21dba00',
_nonce: '0x23b'
}
// Sign a FeeDelegatedSmartContractExecution
> myContract.sign({
from: '0x{address in hex}',
gas: 1000000,
feeDelegation: true,
}, 'methodName', 123).then(console.log)
FeeDelegatedSmartContractExecution {
_type: 'TxTypeFeeDelegatedSmartContractExecution',
_from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x4e43', _r: '0xf7676...', _s: '0x42673...' } ],
_feePayer: '0x0000000000000000000000000000000000000000',
_feePayerSignatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
_value: '0x0',
_input: '0x983b2...',
_chainId: '0x2710',
_gasPrice: '0x5d21dba00',
_nonce: '0x254'
}
// Sign a FeeDelegatedSmartContractExecutionWithRatio
> myContract.sign({
from: '0x{address in hex}',
gas: 1000000,
feeDelegation: true,
feeRatio: 30,
}, 'methodName', 123).then(console.log)
FeeDelegatedSmartContractExecutionWithRatio {
_type: 'TxTypeFeeDelegatedSmartContractExecutionWithRatio',
_from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x4e44', _r: '0x58b06...', _s: '0x637ff...' } ],
_feePayer: '0x0000000000000000000000000000000000000000',
_feePayerSignatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_feeRatio: '0x1e',
_to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
_value: '0x0',
_input: '0x983b2...',
_chainId: '0x2710',
_gasPrice: '0x5d21dba00',
_nonce: '0x262'
}
```
## myContract.signAsFeePayer
```javascript
myContract.signAsFeePayer(options, methodName [, param1 [, param2 [, ...]]])
```
스마트 컨트랙트 배포 또는 스마트 컨트랙트 함수 실행을 위해 수수료 납부자로서 스마트 컨트랙트 트랜잭션에 서명합니다.
스마트 컨트랙트가 배포되었다면 `myContract.signAsFeePayer({ from, feeDelegation: true, feePayer, ... }, 'constructor', byteCode, ...)`와 같이 methodName에 'constructor'를 입력할 수 있습니다.
The transaction type used for this function depends on the `options` or the value defined in `myContract.options`. `signAsFeePayer`는 트랜잭션 수수료 납부자로서 서명하는 함수이기 때문에 `feeDelegation` 필드는 `true`로 정의되어야 합니다. 수수료 납부자의 주소 또한 `feePayer` 필드에 정의되어 있어야 합니다.
* `feeDelegation`이 정의되지 않음: 에러 반환.
* `feeDelegation`이 정의되었지만, `feePayer`는 정의되지 않음: 에러 반환.
* `feeDelegation` is defined to `true` and `feePayer` is defined, but `feeRatio` is not defined: [FeeDelegatedSmartContractDeploy](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractdeploy) / [FeeDelegatedSmartContractExecution](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractexecution)
* `feeDelegation` is defined to `true` and `feePayer` and `feeRatio` are defined: [FeeDelegatedSmartContractDeployWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractdeploywithratio) / [FeeDelegatedSmartContractExecutionWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractexecutionwithratio)
**NOTE** 서명을 하기 위해서는 `caver.wallet`가 `options`나 `myContract.options`의 `feePayer`에 해당하는 키링 인스턴스를 포함해야 합니다.
**참고** `myContract. signAsFeePayer`는 caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1)부터 지원됩니다.
**Parameters**
| Name | Type | Description |
| ---------- | ------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| options | object | The options used for sending. See the table in [methods.methodName.send](#methods-methodname-send) for the details. |
| methodName | string | The method name of the contract function to execute. If you want to sign a transaction for deploying the smart contract, use 'constructor' string instead of method name. |
| parameters | Mixed | (optional) The parameters that get passed to the smart contract function. If you want to sign a smart contract deploy transaction, pass the byteCode and constructor parameters. |
**Return Value**
`Promise` returning [Transaction](https://github.com/klaytn/klaytn-docs-ko/blob/main/docs/dapp/sdk/caver-js/api-references/caver.transaction) - The signed smart contract transaction.
**Example**
```javascript
// Sign a FeeDelegatedSmartContractDeploy
> myContract.signAsFeePayer({ from: '0x{address in hex}', feeDelegation: true, feePayer: '0x{address in hex}', gas: 1000000 }, 'constructor', byteCode, 123).then(console.log)
FeeDelegatedSmartContractDeploy {
_type: 'TxTypeFeeDelegatedSmartContractDeploy',
_from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_feePayerSignatures: [ SignatureData { _v: '0x4e43', _r: '0xe0641...', _s: '0x1d21e...' } ],
_to: '0x',
_value: '0x0',
_input: '0x60806...',
_humanReadable: false,
_codeFormat: '0x0',
_chainId: '0x2710',
_gasPrice: '0x5d21dba00',
_nonce: '0x32a'
}
// Sign a FeeDelegatedSmartContractDeployWithRatio
> myContract.signAsFeePayer({ from: keyring.address, feeDelegation: true, feePayer: '0x{address in hex}', feeRatio: 30, gas: 1000000 }, 'constructor', byteCode, 123).then(console.log)
FeeDelegatedSmartContractDeployWithRatio {
_type: 'TxTypeFeeDelegatedSmartContractDeployWithRatio',
_from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_feePayerSignatures: [ SignatureData { _v: '0x4e44', _r: '0x307bd...', _s: '0x75110...' } ],
_feeRatio: '0x1e',
_to: '0x',
_value: '0x0',
_input: '0x60806...',
_humanReadable: false,
_codeFormat: '0x0',
_chainId: '0x2710',
_gasPrice: '0x5d21dba00',
_nonce: '0x359'
}
// Sign a FeeDelegatedSmartContractExecution
> myContract.signAsFeePayer({
from: '0x{address in hex}',
gas: 1000000,
feeDelegation: true,
feePayer: '0x{address in hex}',
}, 'methodName', 123).then(console.log)
FeeDelegatedSmartContractExecution {
_type: 'TxTypeFeeDelegatedSmartContractExecution',
_from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_feePayerSignatures: [ SignatureData { _v: '0x4e43', _r: '0xc58ba...', _s: '0x76fdb...' } ],
_to: '0x4a9d979707aede18fa674711f3b2fe110fac4e7e',
_value: '0x0',
_input: '0x983b2...',
_chainId: '0x2710',
_gasPrice: '0x5d21dba00',
_nonce: '0x36c'
}
// Sign a FeeDelegatedSmartContractExecutionWithRatio
> myContract.signAsFeePayer({
from: '0x{address in hex}',
gas: 1000000,
feeDelegation: true,
feePayer: '0x{address in hex}',
feeRatio: 30,
}, 'methodName', 123).then(console.log)
FeeDelegatedSmartContractExecutionWithRatio {
_type: 'TxTypeFeeDelegatedSmartContractExecutionWithRatio',
_from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
_feePayerSignatures: [ SignatureData { _v: '0x4e44', _r: '0xeb78d...', _s: '0x2864d...' } ],
_feeRatio: '0x1e',
_to: '0x4a9d979707aede18fa674711f3b2fe110fac4e7e',
_value: '0x0',
_input: '0x983b2...',
_chainId: '0x2710',
_gasPrice: '0x5d21dba00',
_nonce: '0x37b'
}
```
## myContract.call
```javascript
myContract.call('methodName', [param1 [, param2 [, ...]]])
myContract.call(options, 'methodName', [param1 [, param2 [, ...]]])
```
상수형 메서드를 호출하며 트랜잭션을 보내지 않고 그 스마트 컨트랙트 메서드를 Klaytn 가상머신에서 실행합니다. Note that calling cannot alter the smart contract state.
**참고** `myContract.call`는 caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1)부터 지원됩니다.
**Parameters**
| Name | Type | Description |
| ---------- | ------ | ------------------------------------------------------------------------------------------------------------------------------ |
| options | object | (optional) The options used for calling. See the table in [methods.methodName.call](#methods-methodname-call) for the details. |
| methodName | string | The method name of the contract function to call. |
| parameters | Mixed | (optional) The parameters that get passed to the smart contract function. |
**Return Value**
`Promise`가 `Mixed`를 반환: 스마트 컨트랙트 메서드의 리턴값(들) 입니다. 하나를 반환하면, 그대로 반환됩니다. 다수의 반환값이 있는 경우 속성과 인덱스로 구성된 객체로서 반환됩니다.
**Example**
```javascript
> myContract.call('methodName').then(console.log)
Jasmine
> myContract.call({ from: '0x{address in hex}' }, 'methodName', 123).then(console.log)
Test Result
```
## myContract.decodeFunctionCall
```javascript
myContract.decodeFunctionCall(functionCall)
```
Decodes a function call and returns parameters.
**NOTE** `myContract.decodeFunctionCall` is supported since caver-js [v1.6.3](https://www.npmjs.com/package/caver-js/v/1.6.3).
**Parameters**
| Name | Type | Description |
| ------------ | ------ | --------------------------------- |
| functionCall | string | The encoded function call string. |
**Return Value**
| Type | Description |
| ------ | --------------------------------------------------------------------------------------------------------------------------------------------- |
| object | An object which includes plain params. You can use `result[0]` as it is provided to be accessed like an array in the order of the parameters. |
**Examples**
```javascript
// The myContract variable is instantiated with the below abi.
/ [
// {
// constant: true,
// inputs: [{ name: 'key', type: 'string' }],
// name: 'get',
// outputs: [{ name: '', type: 'string' }],
// payable: false,
// stateMutability: 'view',
// type: 'function',
// },
// {
// constant: false,
// inputs: [{ name: 'key', type: 'string' }, { name: 'value', type: 'string' }],
// name: 'set',
// outputs: [],
// payable: false,
// stateMutability: 'nonpayable',
// type: 'function',
// },
// ]
> myContract.decodeFunctionCall('0xe942b5160000000000000000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000036b65790000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000576616c7565000000000000000000000000000000000000000000000000000000')
Result {
'0': '2345675643',
'1': 'Hello!%',
__length__: 2,
myNumber: '2345675643',
mystring: 'Hello!%'
}
```
## myContract.methods
```javascript
myContract.methods.methodName([param1 [, param2 [, ...]]])
myContract.methods['methodName']([param1 [, param2 [, ...]]])
```
호출, 전송, 추정 또는 ABI 인코딩될 수 있는 해당 메소드에 대한 트랜잭션 객체를 생성합니다.
이 스마트 컨트랙트의 메서드는 다음을 통해 이용할 수 있습니다:
* 메서드 이름: `myContract.methods.methodName(123)` 또는 `myContract.methods[methodName](123)`
* 메서드 프로토타입: `myContract.methods['methodName(uint256)'](123)`
* 메서드 서명: `myContract.methods['0x58cf5f10'](123)`
이를 통해 자바스크립트 컨트랙트 객체로부터 이름은 같지만 매개변수가 다른 함수를 호출할 수 있습니다.
## cf) \*function signature (function selector)
The first four bytes of the call data for a function call specifies the function to be called.\
It is the first (left, high-order in big-endian) four bytes of the Keccak-256 (SHA-3) hash of the signature of the function.
The function signature can be given via 2 different methods.\
`1. caver.abi.encodefunctionSignature('funcName(paramType1,paramType2,...)')`\
`2. caver.utils.sha3('funcName(paramType1,paramType2,...)').substr(0, 10)`
ex)
```javascript
caver.abi.encodefunctionSignature('methodName(uint256)')
> 0x58cf5f10
caver.utils.sha3('methodName(uint256)').substr(0, 10)
> 0x58cf5f10
```
**Parameters**
JSON 인터페이스에 정의된 스마트 컨트랙트 메서드에 속하는 모든 메서드의 매개변수
**Return Value**
`Promise`는 `object`를 반환 - 컨트랙트 실행을 위한 인자와 함수가 정의되어 있는 객체입니다:
| Name | Type | Description |
| ---------------------------------------------------- | -------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| arguments | Array | The arguments passed to this method. |
| [call](#methods-methodname-call) | function | The function that will call and execute a constant method in its smart contract on Klaytn Virtual Machine without sending a transaction (cannot alter the smart contract state). |
| [send](#methods-methodname-send) | function | The function that will send a transaction to the Klaytn and execute its method (can alter the smart contract state). |
| [sign](#methods-methodname-sign) | function | The function that will sign a transaction as a sender. The sign function will return signed transaction. |
| [signAsFeePayer](#methods-methodname-signasfeepayer) | function | The function that will sign a transaction as a fee payer. The signAsFeePayer function will return signed transaction. |
| [estimateGas](#methods-methodname-estimategas) | function | The that function will estimate the gas used for the execution. |
| [encodeABI](#methods-methodname-encodeabi) | function | The function that encodes the ABI for this method. This can be sent using a transaction, calling the method, or passing into another smart contract method as its argument. |
**참고** `sign`과 `signAsFeePayer`는 caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1)부터 지원됩니다.
**Example**
```javascript
// Calling a method
> myContract.methods.methodName(123).call({ ... }, function(error, result) { ... })
> myContract.methods.methodName(123).call({ ... }).then((result) => { ... })
// Sending basic transaction and using the promise
> myContract.methods.methodName(123).send({
from: '0x{address in hex}',
...
}).then(function(receipt) {
// receipt can also be a new contract instance, when coming from a "contract.deploy({...}).send()"
})
// Sending basic transaction and using the eventEmitter
> myContract.methods.methodName(123).send({
from: '0x{address in hex}',
...
}).on('transactionHash', function(hash) {
...
})
.on('receipt', function(receipt) {
...
})
.on('error', console.error)
// Sending fee delegation transaction and using the promise
> myContract.methods.methodName(123).send({
from: '0x{address in hex}',
feePayer: '0x{fee-payer address}',
feeDelegation: true,f
...
}).then(function(receipt) {
// receipt can also be a new contract instance, when coming from a "contract.deploy({...}).send()"
})
// Sending partial fee delegation transaction and using the promise
> myContract.methods.methodName(123).send({
from: '0x{address in hex}',
feePayer: '0x{fee-payer address}',
feeDelegation: true,
feeRatio: 30,
...
}).then(function(receipt) {
// receipt can also be a new contract instance, when coming from a "contract.deploy({...}).send()"
})
// sign the basic transaction
> myContract.methods.methodName(123).sign({
from: '0x{address in hex}',
feeDelegation: true,
...
}).then(function(signedTx) { ... })
// sign the fee delegation transaction
> myContract.methods.methodName(123).sign({
from: '0x{address in hex}',
feeDelegation: true,
...
}).then(function(signedTx) { ... })
// sign the partial fee delegation transaction
> myContract.methods.methodName(123).sign({
from: '0x{address in hex}',
feeDelegation: true,
feeRatio: 30,
...
}).then(function(signedTx) { ... })
// sign the fee delegation transaction as a fee payer
> myContract.methods.methodName(123).signAsFeePayer({
from: '0x{address in hex}',
feePayer: '0x{fee-payer address}',
feeDelegation: true,
...
}).then(function(signedTx) { ... })
// sign the partial fee delegation transaction as a fee payer
> myContract.methods.methodName(123).signAsFeePayer({
from: '0x{address in hex}',
feePayer: '0x{fee-payer address}',
feeDelegation: true,
feeRatio: 30,
...
}).then(function(signedTx) { ... })
```
## methods.methodName.call
```javascript
myContract.methods.methodName([param1 [, param2 [, ...]]]).call(options [, callback])
myContract.methods['methodName']([param1 [, param2 [, ...]]]).call(options [, callback])
```
Will call a constant method and execute its smart contract method in the Klaytn Virtual Machine without sending any transaction. Note that calling cannot alter the smart contract state. It is recommended to use [myContract.call](#mycontract-call) provided as a short-cut function.
**Parameters**
| Name | Type | Description |
| -------- | -------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| options | object | (optional) The options used for calling. See the table below for the details. |
| callback | function | (optional) This callback will be fired with the result of the smart contract method execution as the second argument, or with an error object as the first argument. |
The options object can contain the following:
| Name | Type | Description |
| -------- | ------ | -------------------------------------------------------------------------- |
| from | string | (optional) The address which calling contract methods should be made from. |
| gasPrice | string | (optional) The gas price in peb to use for this call. |
| gas | number | (optional) The maximum gas provided for this call (gas limit). |
**Return Value**
`Promise` returning `Mixed` - The return value(s) of the smart contract method. If it returns a single value, it is returned as it is. If it has multiple return values, it returns an object with properties and indices.
**Example**
```javascript
// promise 사용
> myContract.methods.methodName(123).call({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then(function(result) {
...
})
```
```solidity
// Solidity: MULTIPLE RETURN VALUES
contract MyContract {
function myFunction() public returns(uint256 myNumber, string memory myString) {
return (23456, "Hello!%");
}
}
```
```javascript
> var MyContract = new caver.contract(abi, address)
> MyContract.methods.myfunction().call().then(console.log)
Result {
mynumber: '23456',
mystring: 'Hello!%',
0: '23456',
1: 'Hello!%'
}
```
```solidity
// Solidity: SINGLE RETURN VALUE
contract MyContract {
function myfunction() public returns(string memory mystring) {
return "Hello!%";
}
}
```
```javascript
> var MyContract = new caver.contract(abi, address)
> MyContract.methods.myfunction().call().then(console.log)
"Hello!%"
```
## methods.methodName.send
```javascript
myContract.methods.methodName([param1 [, param2 [, ...]]]).send(options [, callback])
myContract.methods['methodName']([param1 [, param2 [, ...]]]).send(options [, callback])
```
Will send a transaction to deploy the smart contract or execute the function of the smart contract. This can alter the smart contract state. It is recommended to use [myContract.send](#mycontract-send) provided as a short-cut function.
If a smart contract is deployed, 'constructor' can be entered in the methodName, such as `myContract.methods.constructor` or `myContract.methods['constructor']`, but it is recommended to use the [myContract.deploy](#mycontract-deploy2) function.
The transaction type used for this function depends on the `options` or the value defined in `myContract.options`. If you want to use a fee-delegated transaction through `methods.methodName.send`, `feeDelegation` and `feePayer` should be set properly.
* `feeDelegation` is not defined or defined to `false`: [SmartContractDeploy](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/basic#smartcontractdeploy) / [SmartContractExecution](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/basic#smartcontractexecution)
* `feeDelegation` is defined to `true`, but `feePayer` is not defined : Throws an error.
* `feeDelegation` is defined to `true` and `feePayer` is defined, but `feeRatio` is not defined: [FeeDelegatedSmartContractDeploy](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractdeploy) / [FeeDelegatedSmartContractExecution](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractexecution)
* `feeDelegation` is defined to `true` and `feePayer` and `feeRatio` are defined: [FeeDelegatedSmartContractDeployWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractdeploywithratio) / [FeeDelegatedSmartContractExecutionWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractexecutionwithratio)
**NOTE** `caver.wallet` must contains keyring instances corresponding to `from` and `feePayer` in `options` or `myContract.options` to make signatures.
**Parameters**
| Name | Type | Description |
| -------- | -------- | ----------------------------------------------------------------------------------------------------------------------- |
| options | object | The options used for sending. See the table below for the details. |
| callback | function | (optional) This callback will be fired first with the "transactionHash", or with an error object as the first argument. |
The options object can contain the following:
| Name | Type | Description |
| ------------- | --------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| from | string | 트랜잭션을 보낼 송신자 주소. If omitted, `myContract.options.from` will be used. |
| gas | number | The maximum gas provided for this transaction (gas limit). |
| gasPrice | string | (선택 사항) 트랜잭션에 사용할 peb 단위의 가스 가격. |
| value | number \\ | string \| BN \| Bignumber |
| feeDelegation | boolean | (optional, default `false`) 수수료 위임 트랜잭션 사용 여부를 나타냅니다. If omitted, `myContract.options.feeDelegation` will be used. |
| feePayer | string | (optional) The address of the fee payer paying the transaction fee. When `feeDelegation` is `true`, the value is set to the `feePayer` field in the transaction. If omitted, `myContract.options.feePayer` will be used. |
| feeRatio | string | (optional) The ratio of the transaction fee the fee payer will be burdened with. If `feeDelegation` is `true` and `feeRatio` is set to a valid value, a partial fee delegation transaction is used. The valid range of this is between 1 and 99. The ratio of 0, or 100 and above are not allowed. If omitted, `myContract.options.feeRatio` will be used. |
**NOTE** `feeDelegation`, `feePayer` and `feeRatio` are supported since caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1).
**Return Value**
`Promise` returns `PromiEvent`
| Type | Description |
| ---------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| PromiEvent | A promise combined event emitter. It will be resolved when the transaction receipt is available. The promise will be resolved with the new contract instance. |
For PromiEvent, the following events are available:
* `transactionHash`: It is fired right after the transaction is sent and a transaction hash is available. Its type is `string`.
* `receipt`: It is fired when the transaction receipt is available. See [caver.rpc.klay.getTransactionReceipt](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.rpc/klay#caver-rpc-klay-gettransactionreceipt) for more details. Its type is `object`.
* `error`: It is fired if an error occurs during sending. On an out-of-gas error, the second parameter is the receipt. Its type is `Error`.
**Example**
```javascript
// using the promise
> myContract.methods.methodName(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then(function(receipt) {
// receipt can also be a new contract instance, when coming from a "contract.deploy({...}).send()"
})
// using the event emitter
> myContract.methods.methodName(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.on('transactionHash', function(hash) {
...
})
.on('receipt', function(receipt) {
console.log(receipt)
})
.on('error', console.error) // If there is an out-of-gas error, the second parameter is the receipt.
// receipt example
{
"transactionHash": "0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b",
"transactionIndex": 0,
"blockHash": "0xef95f2f1ed3ca60b048b4bf67cde2195961e0bba6f70bcbea9a2c4e133e34b46",
"blocknumber": 3,
"contractAddress": "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe",
"gasUsed": 30234,
"events": {
"eventName": {
returnValues: {
myIndexedParam: 20,
myOtherIndexedParam: '0x123456789...',
myNonIndexParam: 'My string'
},
raw: {
data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
},
event: 'eventName',
signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
logIndex: 0,
transactionIndex: 0,
transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
blocknumber: 1234,
address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
},
"MyOtherEvent": {
...
},
"MyMultipleEvent":[{...}, {...}] // If there are multiples of the same events, they will be in an array.
}
}
// Deploy the contract
> myContract.methods.constructor('0x{byte code}', 123).send({ from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe', gas: 1000000 })
> myContract.methods['constructor']('0x{byte code}', 123).send({ from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe', gas: 1000000 })
```
## methods.methodName.sign
```javascript
myContract.methods.methodName([param1 [, param2 [, ...]]]).sign(options)
myContract.methods['methodName']([param1 [, param2 [, ...]]]).sign(options)
```
Signs a smart contract transaction as a sender to deploy the smart contract or execute the function of the smart contract. It is recommended to use [myContract.sign](#mycontract-sign) provided as a short-cut function.
If a smart contract is deployed, 'constructor' can be entered in the methodName, such as `myContract.methods.constructor` or `myContract.methods['constructor']`.
The transaction type used for this function depends on the `options` or the value defined in `myContract.options`. If you want to use a fee-delegated transaction through `methods.methodName.sign`, `feeDelegation` should be defined as `true`.
* `feeDelegation` is not defined or defined to `false`: [SmartContractDeploy](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/basic#smartcontractdeploy) / [SmartContractExecution](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/basic#smartcontractexecution)
* `feeDelegation` is defined to `true`, but `feeRatio` is not defined: [FeeDelegatedSmartContractDeploy](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractdeploy) / [FeeDelegatedSmartContractExecution](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractexecution)
* `feeDelegation` is defined to `true` and `feeRatio` is defined: [FeeDelegatedSmartContractDeployWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractdeploywithratio) / [FeeDelegatedSmartContractExecutionWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractexecutionwithratio)
**NOTE** `caver.wallet` must contains keyring instances corresponding to `from` in `options` or `myContract.options` to make signatures.
**NOTE** `methods.methodName.sign` is supported since caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1).
**Parameters**
| Name | Type | Description |
| ------- | ------ | -------------------------------------------------------------------------------------------------------------------------------------------- |
| options | object | The options used for creating a transaction. See the parameter table in [methods.methodName.send](#methods-methodname-send) for the details. |
**Return Value**
`Promise` returning [Transaction](https://github.com/klaytn/klaytn-docs-ko/blob/main/docs/dapp/sdk/caver-js/api-references/caver.transaction) - The signed smart contract transaction.
**Example**
```javascript
// Sign a SmartContractDeploy transaction
> myContract.methods.constructor(byteCode, 123).sign({ from: '0x{address in hex}', gas: 1000000 }).then(console.log)
SmartContractDeploy {
_type: 'TxTypeSmartContractDeploy',
_from: '0x60498fefbf1705a3db8d7bb5c80d5238956343e5',
_gas: '0xf4240',
_signatures: [
SignatureData {
_v: '0x07f6',
_r: '0x26a05...',
_s: '0x3e3e4...'
}
],
_to: '0x',
_value: '0x0',
_input: '0x60806...',
_humanReadable: false,
_codeFormat: '0x0',
_chainId: '0x3e9',
_gasPrice: '0x5d21dba00',
_nonce: '0x2f6'
}
> myContract.methods['constructor'](byteCode, 123).sign({ from: '0x{address in hex}', gas: 1000000 }).then(console.log)
// Sign a FeeDelegatedSmartContractDeploy transaction
> myContract.methods.constructor(byteCode, 123).sign({ from: '0x{address in hex}', feeDelegation: true, gas: 1000000 }).then(console.log)
FeeDelegatedSmartContractDeploy {
_type: 'TxTypeFeeDelegatedSmartContractDeploy',
_from: '0x60498fefbf1705a3db8d7bb5c80d5238956343e5',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x07f5', _r: '0xa74f7...', _s: '0x0991e...' } ],
_feePayer: '0x0000000000000000000000000000000000000000',
_feePayerSignatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_to: '0x',
_value: '0x0',
_input: '0x60806...',
_humanReadable: false,
_codeFormat: '0x0',
_chainId: '0x3e9',
_gasPrice: '0x5d21dba00',
_nonce: '0x2f6'
}
> myContract.methods['constructor'](byteCode, 123).sign({ from: '0x{address in hex}', feeDelegation: true, gas: 1000000 }).then(console.log)
// Sign a SmartContractExecution transaction
> myContract.methods.methodName('0x...').sign({ from: '0x{address in hex}', gas: 1000000 }).then(console.log)
SmartContractExecution {
_type: 'TxTypeSmartContractExecution',
_from: '0x60498fefbf1705a3db8d7bb5c80d5238956343e5',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x07f5', _r: '0xafbf9...', _s: '0x10ea0...' } ],
_to: '0xbc6723431a57abcacc4016ae664ee778d313ca6e',
_value: '0x0',
_input: '0x983b2d5600000000000000000000000060498fefbf1705a3db8d7bb5c80d5238956343e5',
_chainId: '0x3e9',
_gasPrice: '0x5d21dba00',
_nonce: '0x2f6'
}
> myContract.methods['methodName']('0x...').sign({ from: '0x{address in hex}', gas: 1000000 }).then(console.log)
// Sign a FeeDelegatedSmartContractExecution transaction
> myContract.methods.methodName('0x...').sign({ from: '0x{address in hex}', feeDelegation: true, gas: 1000000 }).then(console.log)
FeeDelegatedSmartContractExecution {
_type: 'TxTypeFeeDelegatedSmartContractExecution',
_from: '0x60498fefbf1705a3db8d7bb5c80d5238956343e5',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x07f6', _r: '0xdfc14...', _s: '0x38b9c...' } ],
_feePayer: '0x0000000000000000000000000000000000000000',
_feePayerSignatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_to: '0xbc6723431a57abcacc4016ae664ee778d313ca6e',
_value: '0x0',
_input: '0x983b2d5600000000000000000000000060498fefbf1705a3db8d7bb5c80d5238956343e5',
_chainId: '0x3e9',
_gasPrice: '0x5d21dba00',
_nonce: '0x2f6'
}
> myContract.methods['methodName']('0x...').sign({ from: '0x{address in hex}', feeDelegation: true, gas: 1000000 }).then(console.log)
```
## methods.methodName.signAsFeePayer
```javascript
myContract.methods.methodName([param1 [, param2 [, ...]]]).signAsFeePayer(options)
myContract.methods['methodName']([param1 [, param2 [, ...]]]).signAsFeePayer(options)
```
Signs a smart contract transaction as a fee payer to deploy the smart contract or execute the function of the smart contract. It is recommended to use [myContract.signAsFeePayer](#mycontract-signasfeepayer) provided as a short-cut function.
If a smart contract is deployed, 'constructor' can be entered in the methodName, such as `myContract.methods.constructor` or `myContract.methods['constructor']`.
The transaction type used for this function depends on the `options` or the value defined in `myContract.options`. The `signAsFeePayer` is a function that signs as a transaction fee payer, so `feeDelegation` field must be defined as `true`. Also, the address of the fee payer must be defined in the `feePayer` field.
* `feeDelegation` is not defined : Throws an error.
* `feeDelegation` is defined, but `feePayer` is not defined : Throws an error.
* `feeDelegation` is defined to `true` and `feePayer` is defined, but `feeRatio` is not defined: [FeeDelegatedSmartContractDeploy](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractdeploy) / [FeeDelegatedSmartContractExecution](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/fee-delegation#feedelegatedsmartcontractexecution)
* `feeDelegation` is defined to `true` and `feePayer` and `feeRatio` are defined: [FeeDelegatedSmartContractDeployWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractdeploywithratio) / [FeeDelegatedSmartContractExecutionWithRatio](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/caver.transaction/partial-fee-delegation#feedelegatedsmartcontractexecutionwithratio)
**NOTE** `caver.wallet` must contains keyring instances corresponding to `feePayer` in `options` or `myContract.options` to make signatures.
**NOTE** `methods.methodName.signAsFeePayer` is supported since caver-js [v1.6.1](https://www.npmjs.com/package/caver-js/v/1.6.1).
**Parameters**
| Name | Type | Description |
| ------- | ------ | -------------------------------------------------------------------------------------------------------------------------------------------- |
| options | object | The options used for creating a transaction. See the parameter table in [methods.methodName.send](#methods-methodname-send) for the details. |
**Return Value**
`Promise` returning [Transaction](https://github.com/klaytn/klaytn-docs-ko/blob/main/docs/dapp/sdk/caver-js/api-references/caver.transaction) - The signed smart contract transaction.
**Example**
```javascript
// Sign a FeeDelegatedSmartContractDeploy transaction
> myContract.methods.constructor(byteCode, 123).signAsFeePayer({ from: '0x{address in hex}', feeDelegation: true, feePayer: '0x{address in hex}', gas: 1000000 }).then(console.log)
> FeeDelegatedSmartContractDeploy {
_type: 'TxTypeFeeDelegatedSmartContractDeploy',
_from: '0x60498fefbf1705a3db8d7bb5c80d5238956343e5',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_feePayer: '0x60498fefbf1705a3db8d7bb5c80d5238956343e5',
_feePayerSignatures: [ SignatureData { _v: '0x07f6', _r: '0x2c385...', _s: '0x7fa79...' } ],
_to: '0x',
_value: '0x0',
_input: '0x60806...',
_humanReadable: false,
_codeFormat: '0x0',
_chainId: '0x3e9',
_gasPrice: '0x5d21dba00',
_nonce: '0x2f6'
}
> myContract.methods['constructor'](byteCode, 123).signAsFeePayer({ from: '0x{address in hex}', feeDelegation: true, feePayer: '0x{address in hex}', gas: 1000000 }).then(console.log)
// Sign a FeeDelegatedSmartContractExecution transaction
> myContract.methods.methodName(123).signAsFeePayer({ from: '0x{address in hex}', feeDelegation: true, feePayer: '0x{address in hex}', gas: 1000000 }).then(console.log)
> FeeDelegatedSmartContractExecution {
_type: 'TxTypeFeeDelegatedSmartContractExecution',
_from: '0x60498fefbf1705a3db8d7bb5c80d5238956343e5',
_gas: '0xf4240',
_signatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
_feePayer: '0x60498fefbf1705a3db8d7bb5c80d5238956343e5',
_feePayerSignatures: [ SignatureData { _v: '0x07f6', _r: '0x793eb...', _s: '0x0f776...' } ],
_to: '0x294b2618f29714732cfc202d7be53bf5efee90dd',
_value: '0x0',
_input: '0x983b2d5600000000000000000000000060498fefbf1705a3db8d7bb5c80d5238956343e5',
_chainId: '0x3e9',
_gasPrice: '0x5d21dba00',
_nonce: '0x2f6'
}
> myContract.methods['methodName'](123).signAsFeePayer({ from: '0x{address in hex}', feeDelegation: true, feePayer: '0x{address in hex}', gas: 1000000 }).then(console.log)
```
## methods.methodName.estimateGas
```javascript
myContract.methods.methodName([param1 [, param2 [, ...]]]).estimateGas(options [, callback])
```
Will estimate the gas that a method execution will take when executed in the Klaytn Virtual Machine. The estimation can differ from the actual gas used when later sending a transaction, as the state of the smart contract can be different at that time.
**Parameters**
| Name | Type | Description |
| -------- | -------- | --------------------------------------------------------------------------------------------------------------------------------------------------- |
| options | object | (optional) The options used for calling. See the table below for the details. |
| callback | function | (optional) This callback will be fired with the result of the gas estimation as the second argument, or with an error object as the first argument. |
The options object can contain the following:
| Name | Type | Description |
| ----- | --------- | ----------------------------------------------------------------------------------------------------------------------------- |
| from | string | (optional) The address from which calling the contract method should be made. |
| gas | number | (optional) The maximum gas provided for this call (gas limit). 특정 값을 설정하면 가스 부족 오류를 감지하는 데 도움이 됩니다. 모든 가스가 사용되면 같은 숫자를 반환합니다. |
| value | number \\ | string \| BN \| Bignumber |
**Return Value**
`Promise`는 `number`를 반환합니다.
| Type | Description |
| ------ | ------------------------------------------------ |
| number | The used gas for the simulated call/transaction. |
**Example**
```javascript
> myContract.methods.methodName(123).estimateGas({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then(function(gasAmount) {
...
})
.catch(function(error) {
...
})
```
## methods.methodName.encodeABI
```javascript
myContract.methods.methodName([param1 [, param2[, ...]]]).encodeABI()
```
이 메소드에 대한 ABI를 인코딩합니다. This can be used to send a transaction or call a method, or pass it into another smart contract method as arguments.
**Parameters**
Parameters of any method that belongs to this smart contract, defined in the JSON interface.
**Return Value**
| Type | Description |
| ------ | ----------------------------------- |
| string | 트랜잭션 또는 호출을 통해 전송할 인코딩된 ABI 바이트 코드. |
**Example**
```javascript
> myContract.methods.methodName(123).encodeABI()
'0x58cf5f1000000000000000000000000000000000000000000000000000000000000007B'
```
## myContract.once
```javascript
myContract.once(event [, options], callback)
```
Subscribes to an event and unsubscribes immediately after the first event or error. 단일 이벤트에 대해서만 발생합니다.
**Parameters**
| Name | Type | Description |
| -------- | -------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| event | string | The name of the event in the contract, or `allEvents` to get all events. |
| options | object | (optional) The options used for subscription. See the table below for the details. |
| callback | function | 이 콜백은 첫 번째 이벤트를 두 번째 인수로, 또는 오류를 첫 번째 인수로 하여 발생됩니다. See [myContract.getPastEvents](#getpastevents) for details about the event structure. |
The options object can contain the following:
| Name | Type | Description |
| ------ | ------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| filter | object | (optional) Lets you filter events by indexed parameters, *e.g.*, `{filter: {mynumber: [12,13]}}` means all events where "mynumber" is 12 or 13. |
| topics | Array | (optional) This allows you to manually set the topics for the event filter. Given the filter property and event signature, `topic[0]` would not be set automatically. |
**Return Value**
`Promise` returns `object` - An event object. For more detail about event object, please refer to [myContract.getPastEvents](#getpastevents).
**Example**
```javascript
> myContract.once('eventName', {
filter: {myIndexedParam: [20,23], myOtherIndexedParam: '0x123456789...'}, // Using an array means OR: e.g. 20 or 23
}, function(error, event) { console.log(event) })
// event output example
{
returnValues: {
myIndexedParam: 20,
myOtherIndexedParam: '0x123456789...',
myNonIndexParam: 'My string'
},
raw: {
data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
},
event: 'eventName',
signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
logIndex: 0,
transactionIndex: 0,
transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
blocknumber: 1234,
address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
}
```
## myContract.subscribe
```javascript
myContract.subscribe(event [, options], callback)
```
Subscribes to an event. This function works same as [myContract.events.eventName](#mycontract-events).
You can unsubscribe an event by calling the `unsubscribe` function of the subscription object returned by the `subscribe` function.
**NOTE** `myContract.subscribe` is supported since caver-js [v1.9.1-rc.1](https://www.npmjs.com/package/caver-js/v/1.9.1-rc.1).
**Parameters**
| Name | Type | Description |
| -------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| event | string | The name of the event in the contract, or `allEvents` to get all events. |
| options | object | (optional) The options used for subscription. See the table below for the details. |
| callback | function | This callback will be fired for the first event as the second argument, or an error as the first argument. See [myContract.getPastEvents](#getpastevents) for details about the event structure. |
The options object can contain the following:
| Name | Type | Description |
| ------ | ------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| filter | object | (optional) Lets you filter events by indexed parameters, *e.g.*, `{filter: {mynumber: [12,13]}}` means all events where "mynumber" is 12 or 13. |
| topics | Array | (optional) This allows you to manually set the topics for the event filter. Given the filter property and event signature, `topic[0]` would not be set automatically. |
**Return Value**
`Promise` returns `object` - An event object. For more detail about event object, please refer to [myContract.getPastEvents](#getpastevents).
**Example**
```javascript
> const subscription = myContract.subscribe('eventName', {
filter: {myIndexedParam: [20,23], myOtherIndexedParam: '0x123456789...'}, // Using an array means OR: e.g. 20 or 23
}, function(error, event) { console.log(event) })
{
returnValues: {
myIndexedParam: 20,
myOtherIndexedParam: '0x123456789...',
myNonIndexParam: 'My string'
},
raw: {
data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
topics: ['0xfd43a...', '0x7f9fa...']
},
event: 'eventName',
signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
logIndex: 0,
transactionIndex: 0,
transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
blocknumber: 1234,
address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
}
> subscription.unsubscribe() // unsubscribe the event
```
## myContract.events
```javascript
myContract.events.eventName([options][, callback])
```
Subscribes to an event.
**Parameters**
| Name | Type | Description |
| -------- | -------- | ---------------------------------------------------------------------------------------------------------------- |
| options | object | (optional) The options used for subscription. See the table below for the details. |
| callback | function | (optional) This callback will be fired for each event as the second argument, or an error as the first argument. |
The options object can contain the following:
| Name | Type | Description |
| --------- | ------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| filter | object | (optional) Lets you filter events by indexed parameters, *e.g.*, `{filter: {mynumber: [12,13]}}` means all events where "mynumber" is 12 or 13. |
| fromBlock | number | (optional) The block number from which to get events. |
| topics | Array | (optional) This allows you to manually set the topics for the event filter. Given the filter property and event signature, `topic[0]` would not be set automatically. |
**Return Value**
`EventEmitter`: The event emitter has the following events:
| Name | Type | Description |
| --------- | ------ | ----------------------------------------------------------------------------------------- |
| data | object | Fires on each incoming event with the event object as an argument. |
| connected | string | Fires once after the subscription successfully connected. It returns the subscription ID. |
| error | object | Fires when an error in the subscription occurs. |
**NOTE** `connected` is available with caver-js [v1.5.7](https://www.npmjs.com/package/caver-js/v/1.5.7).
The structure of the returned event `object` looks as follows:
| Name | Type | Description |
| ---------------- | -------------- | --------------------------------------------------------------------------------------------------------------------------------------- |
| event | string | The event name. |
| signature | string \\ | `null` |
| address | string | Address which from this event originated. |
| returnValues | object | The return values coming from the event, *e.g.*, `{myVar: 1, myVar2: '0x234...'}`. |
| logIndex | number | Integer of the event index position in the block. |
| transactionIndex | number | Integer of the transaction's index position where the event was created. |
| transactionHash | 32-byte string | Hash of the transaction this event was created in. `null` when it is still pending. |
| blockHash | 32-byte string | Hash of the block this event was created in. `null` when it is still pending. |
| blocknumber | number | The block number this log was created in. `null` when still pending. |
| raw\.data | string | The data containing non-indexed log parameter. |
| raw\.topics | Array | An array with a maximum of four 32-byte topics, and topic 1-3 contains indexed parameters of the event. |
| id | string | A log identifier. It is made through concatenating "log\_" string with `keccak256(blockHash + transactionHash + logIndex).substr(0, 8)` |
**Example**
```javascript
> myContract.events.eventName({
filter: {myIndexedParam: [20,23], myOtherIndexedParam: '0x123456789...'}, // Using an array means OR: e.g. 20 or 23
fromBlock: 0
}, function(error, event) { console.log(event) })
.on('connected', function(subscriptionId){
console.log(subscriptionId)
})
.on('data', function(event){
console.log(event) // same results as the optional callback above
})
.on('error', console.error)
// event output example
{
returnValues: {
myIndexedParam: 20,
myOtherIndexedParam: '0x123456789...',
myNonIndexParam: 'My string'
},
raw: {
data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
},
event: 'eventName',
signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
logIndex: 0,
transactionIndex: 0,
transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
blocknumber: 1234,
address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',
id: 'log_41d221bc',
}
```
## events.allEvents
```javascript
myContract.events.allEvents([options] [, callback])
```
Same as [myContract.events](#mycontract-events) but receives all events from this smart contract. Optionally, the filter property can filter those events.
## getPastEvents
```javascript
myContract.getPastEvents(event [, options] [, callback])
```
Gets past events for this contract.
**Parameters**
| Name | Type | Description |
| -------- | -------- | ----------------------------------------------------------------------------------------------------------------------------- |
| event | string | The name of the event in the contract, or `"allEvents"` to get all events. |
| options | object | (optional) The options used for subscription. See the table below for the details. |
| callback | function | (optional) This callback will be fired with an array of event logs as the second argument, or an error as the first argument. |
To options object can contain the following:
| Name | Type | Description |
| --------- | ------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| filter | object | (optional) Lets you filter events by indexed parameters, *e.g.*, `{filter: {mynumber: [12,13]}}` means all events where "mynumber" is 12 or 13. |
| fromBlock | number | (optional) The block number from which to get events. |
| toBlock | number | (optional) The block number to get events up to (defaults to `"latest"`). |
| topics | Array | (optional) This allows manually setting the topics for the event filter. Given the filter property and event signature, `topic[0]` would not be set automatically. |
**Return Value**
`Promise` returns `Array` - An array with the past event objects, matching the given event name and filter.
An event object can contain the following:
| Name | Type | Description |
| ---------------- | --------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| event | string | The event name. |
| signature | string \\ | `null` |
| address | string | Address this event originated from. |
| returnValues | object | The return values coming from the event, e.g. {myVar: 1, myVar2: '0x234...'}. |
| logIndex | number | The event index position in the block. |
| transactionIndex | number | The transaction’s index position the event was created in. |
| transactionHash | string | The hash of the transaction this event was created in. |
| blockHash | string | The hash of the block this event was created in. null when it’s still pending. |
| blockNumber | number | The block number this log was created in. null when still pending. |
| raw | object | An object defines `data` and `topic`. `raw.data` containing non-indexed log parameter. `raw.topic` is an array with a maximum of four 32 Byte topics, and topic 1-3 contains indexed parameters of the event. |
**Example**
```javascript
> myContract.getPastEvents('eventName', {
filter: {myIndexedParam: [20,23], myOtherIndexedParam: '0x123456789...'}, // Using an array means OR: e.g. 20 or 23
fromBlock: 0,
toBlock: 'latest'
}, function(error, events) { console.log(events) })
.then(function(events) {
console.log(events) // same results as the optional callback above
})
[{
returnValues: {
myIndexedParam: 20,
myOtherIndexedParam: '0x123456789...',
myNonIndexParam: 'My string'
},
raw: {
data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
},
event: 'eventName',
signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
logIndex: 0,
transactionIndex: 0,
transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
blocknumber: 1234,
address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
},{
...
}]
```