caver.klay.Contract

스마트 컨트랙트와 상호작용하는 데 사용되는 caver-js 객체입니다.

The caver.klay.Contract object makes it easy to interact with smart contracts on the Klaytn blockchain. When you create a new contract object, you give it the JSON interface of the respective smart contract and caver will auto convert all calls into low level ABI calls over RPC for you.

This allows you to interact with smart contracts as if they were JavaScript objects.

new contract

new caver.klay.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

The JSON interface for the contract to instantiate

address

String

(optional) The address of the smart contract to call. Can be added later using myContract.options.address = '0x1234..'

options

Object

(optional) The options of the contract. See the table below for the details.

The options object contains the following:

Name
Type
Description

from

String

(optional) The address from which transactions should be made.

gasPrice

String

(optional) The gas price in peb to use for transactions.

gas

Number

(optional) The maximum gas provided for a transaction (gas limit).

data

String

(optional) The byte code of the contract. Used when the contract gets deployed.

Return Value

Type
Description

Object

The contract instance with all its methods and events.

Example

var myContract = new caver.klay.Contract([...], '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe', {
      from: '0x1234567890123456789012345678901234567891', // default from address
      gasPrice: '25000000000' // default gas price in peb, 25 Gpeb in this case
});

var myContract = new caver.klay.Contract([...], 'myContract', {
      from: '0x1234567890123456789012345678901234567891', // default from address
      gasPrice: '25000000000' // default gas price in peb, 25 Gpeb in this case
});

options

myContract.options

The options object for the contract instance. from, gas and gasPrice are used as fallback values when sending transactions.

Properties

Name
Type
Description

address

String

jsonInterface

Array

data

String

The byte code of the contract. Used when the contract gets deployed.

from

String

트랜잭션이 만들어진 송신자 주소.

gasPrice

String

The gas price in peb to use for transactions.

gas

Number

The maximum gas provided for a transaction (gas limit).

Example

> myContract.options;
{
    address: '0x1234567890123456789012345678901234567891',
    jsonInterface: [...],
    from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',
    gasPrice: '10000000000000',
    gas: 1000000
}

> 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

options.address

myContract.options.address

The address used for this contract instance myContract. All transactions generated by caver-js from this contract will contain this address as the "to". 주소는 소문자로 저장됩니다.

Property

Name
Type
Description

address

String \

null

Example

>  myContract.options.address;
'0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae'

// set a new address
>  myContract.options.address = '0x1234FFDD...';

options.jsonInterface

myContract.options.jsonInterface

The JSON interface object derived from the ABI of this contract myContract.

Property

Name
Type
Description

jsonInterface

Array

The JSON interface for this contract. Re-setting this will regenerate the methods and events of the contract instance.

Example

> myContract.options.jsonInterface;
[{
      "type":"function",
      "name":"foo",
      "inputs": [{"name":"a","type":"uint256"}],
      "outputs": [{"name":"b","type":"address"}]
 },{
      "type":"event",
      "name":"Event"
      "inputs": [{"name":"a","type":"uint256","indexed":true},{"name":"b","type":"bytes32","indexed":false}],
 }]

// set a new interface
> myContract.options.jsonInterface = [...];

clone

myContract.clone()

Clones the current contract instance.

Parameters

None

Return Value

Type
Description

Object

The new cloned contract instance.

Example

> var contract1 = new caver.klay.Contract(abi, address, {gasPrice: '12345678', from: fromAddress});
> var contract2 = contract1.clone();
> contract2.options.address = address2;
> (contract1.options.address !== contract2.options.address);
true

deploy

myContract.deploy(options)

컨트랙트를 Klaytn 블록체인에 배포합니다. After successful deployment, the promise will be resolved with a new contract instance.

Parameters

options: 배포에 사용되는 옵션 객체:

Name
Type
Description

data

String

The byte code of the contract.

arguments

Array

(optional) The arguments that get passed to the constructor on deployment.

Return Value

Object: 트랜잭션 객체:

Type
Description

Array

arguments: 이전에 메소드에 전달되었던 인자. 이들은 변경될 수 있습니다.

Function

Function

Function

Example

> 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);
  });

methods

myContract.methods.myMethod([param1 [, param2 [, ...]]])

Creates a transaction object for that method, which then can be called, sent, estimated or ABI encoded.

이 스마트 컨트랙트의 메소드는 다음을 통해 이용할 수 있습니다:

  • 이름: myContract.methods.myMethod(123)

  • 매개변수가 있는 이름: myContract.methods['myMethod(uint256)'](123)

  • The signature*: myContract.methods['0x58cf5f10'](123)

This allows calling functions with the same name but different parameters from the JavaScript contract object.

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 made by 2 different methods. 1. caver.klay.abi.encodeFunctionSignature('funcName(paramType1,paramType2,...)') 2. caver.utils.sha3('funcName(paramType1,paramType2,...)').substr(0, 10)

ex)

caver.klay.abi.encodeFunctionSignature('myMethod(uint256)')
> 0x58cf5f10

caver.utils.sha3('myMethod(uint256)').substr(0, 10)
> 0x58cf5f10

Parameters

모든 메소드의 매개변수는 JSON 인터페이스에 정의된 스마트 컨트랙트 메소드에 의존합니다.

Return Value

Object: The transaction object:

Type
Description

Array

arguments: The arguments passed to the method before. They can be changed.

Function

Function

Function

Function

Example

// calling a method
> myContract.methods.myMethod(123).call({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'}, function(error, result) {
      ...
  });

// or sending and using a promise
> myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
  .then(function(receipt) {
    // receipt can also be a new contract instance, when coming from a "contract.deploy({...}).send()"
  });

// or sending and using the events
> myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
  .on('transactionHash', function(hash) {
      ...
  })
  .on('receipt', function(receipt) {
      ...
  })
  .on('error', console.error);

methods.myMethod.call

myContract.methods.myMethod([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.

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 the call “transaction” should be made from.

gasPrice

String

(optional) The gas price in peb to use for this call "transaction".

gas

Number

(optional) The maximum gas provided for this call "transaction" (gas limit).

Return Value

Promise returns 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, they are returned as an object with properties and indices.

Example

// using the callback
> myContract.methods.myMethod(123).call({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'}, function(error, result) {
      ...
  });

// using the promise
> myContract.methods.myMethod(123).call({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
  .then(function(result) {
      ...
  });
// Solidity: MULTI-ARGUMENT RETURN
contract MyContract {
    function myFunction() returns(uint256 myNumber, string myString) {
        return (23456, "Hello!%");
    }
}
> var MyContract = new caver.klay.Contract(abi, address);
> MyContract.methods.myFunction().call().then(console.log);
Result {
      myNumber: '23456',
      myString: 'Hello!%',
      0: '23456', // these are here as fallbacks if the name is not known or given
      1: 'Hello!%'
}
// Solidity: SINGLE-ARGUMENT RETURN
contract MyContract {
    function myFunction() returns(string myString) {
        return "Hello!%";
    }
}
> var MyContract = new caver.klay.Contract(abi, address);
> MyContract.methods.myFunction().call().then(console.log);
"Hello!%"

methods.myMethod.send

myContract.methods.myMethod([param1 [, param2 [, ...]]]).send(options [, callback])

스마트 컨트랙트에 트랜잭션을 보내고 그 메소드를 실행합니다. Note that this can alter the smart contract state.

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

The address from which the transaction should be sent.

gasPrice

String

(optional) The gas price in peb to use for this transaction.

gas

Number

The maximum gas provided for this transaction (gas limit).

value

Number \

String | BN | BigNumber

Return Value

callback은 32바이트 트랜잭션 해시를 반환합니다.

PromiEvent: 프로미스(promise)가 조합된 이벤트 이미터(event emitter). Will be resolved when the transaction receipt is available, or if this send() is called from a someContract.deploy(), then the promise will be resolved with the new contract instance. 추가로 다음과 같은 이벤트를 사용할 수 있습니다:

Name
Type
Description

transactionHash

String

트랜잭션이 전송된 직후 및 트랜잭션 해시를 사용할 수 있을 때 발생합니다.

receipt

Object

error

Error

전송 중 오류가 발생하면 발생됩니다. On an out-of-gas error, the second parameter is the receipt.

Example

// using the callback
> myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'}, function(error, transactionHash) {
    ...
  });

// using the promise
> myContract.methods.myMethod(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.myMethod(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": {
     "MyEvent": {
       returnValues: {
         myIndexedParam: 20,
         myOtherIndexedParam: '0x123456789...',
         myNonIndexParam: 'My String'
       },
       raw: {
         data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
         topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
       },
       event: 'MyEvent',
       signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
       logIndex: 0,
       transactionIndex: 0,
       transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
       blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
       blockNumber: 1234,
       address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
    },
    "MyOtherEvent": {
      ...
    },
    "MyMultipleEvent":[{...}, {...}] // If there are a multiple of the same events, they will be in an array.
  }
}

methods.myMethod.estimateGas

myContract.methods.myMethod([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 the call "transaction" should be made.

gas

Number

(optional) The maximum gas provided for this call "transaction" (gas limit). Setting a specific value helps to detect out of gas errors. If all gas is used, it will return the same number.

value

Number \

String | BN | BigNumber

Return Value

PromiseNumber를 반환합니다 - 모의 호출/트랜잭션에 사용된 가스.

Example

// using the callback
> myContract.methods.myMethod(123).estimateGas({gas: 5000000}, function(error, gasAmount) {
    if(gasAmount == 5000000)
      console.log('Method ran out of gas');
  });

// using the promise
> myContract.methods.myMethod(123).estimateGas({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
  .then(function(gasAmount) {
    ...
  })
  .catch(function(error) {
    ...
  });

methods.myMethod.encodeABI

myContract.methods.myMethod([param1 [, param2[, ...]]]).encodeABI()

Encodes the ABI for this method. This can be used to send a transaction, call a method, or pass it into another smart contract method as arguments.

Parameters

None

Return Value

Type
Description

String

The encoded ABI byte code to send via a transaction or call.

Example

> myContract.methods.myMethod(123).encodeABI();
'0x58cf5f1000000000000000000000000000000000000000000000000000000000000007B'

once

myContract.once(event [, options], callback)

Subscribes to an event and unsubscribes immediately after the first event or error. Will only fire for a single event.

Parameters

Name
Type
Description

event

String

컨트랙트, 또는 모든 이벤트를 받기 위한 "allEvents"에서의 이벤트 이름.

options

Object

(optional) The options used for deployment. See the table below for the details.

callback

Function

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. 필터 특성 및 이벤트 서명이 제공되면, topic[0] 가 자동으로 설정되지 않습니다.

Return Value

undefined

Example

> myContract.once('MyEvent', {
    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: 'MyEvent',
    signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    logIndex: 0,
    transactionIndex: 0,
    transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
    blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    blockNumber: 1234,
    address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
}

events

myContract.events.MyEvent([options][, callback])

이벤트를 구독합니다.

Parameters

Name
Type
Description

options

Object

(optional) The options used for deployment. 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 on.

topics

Array

(optional) This allows to manually set the topics for the event filter. If given the filter property and event signature, topic[0] will not be set automatically.

Return Value

EventEmitter: 이벤트 이미터는 다음 이벤트를 가집니다:

Name
Type
Description

data

Object

이벤트 객체를 인수로 각 수신 이벤트를 발생합니다.

error

Object

구독 오류가 발생하면 발생합니다.

반환된 이벤트 Object의 구조는 다음과 같습니다:

Name
Type
Description

event

String

이벤트 이름.

signature

String \

null

address

String

이 이벤트가 발생한 주소.

returnValues

Object

The return values coming from the event, e.g., {myVar: 1, myVar2: '0x234...'}.

logIndex

Number

블록에서 이벤트 인덱스 위치의 정수값.

transactionIndex

Number

이벤트가 생성된 트랜잭션의 인덱스 위치의 정수값.

transactionHash

32-byte String

이 이벤트가 생성된 블록의 해시. 아직 보류 중인 경우 null.

blockHash

32-byte String

Hash of the block this event was created in. null when it is still pending.

blockNumber

Number

이 로그가 생성된 블록 번호. 아직 보류 중인 경우 null.

raw.data

String

색인화되지 않은 로그 매개변수를 포함하는 데이터.

raw.topics

Array

최대 4개의 32바이트 주제를 가진 배열, 주제 1-3은 이벤트의 색인화된 매개변수가 포함됩니다.

id

String

로그 식별자. It is made through concatenating "log_" string with keccak256(blockHash + transactionHash + logIndex).substr(0, 8)

Example

> myContract.events.MyEvent({
    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('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: 'MyEvent',
    signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    logIndex: 0,
    transactionIndex: 0,
    transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
    blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    blockNumber: 1234,
    address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',
    id: 'log_41d221bc',
}

events.allEvents

myContract.events.allEvents([options] [, callback])

Same as events but receives all events from this smart contract. 선택적으로 filter 속성은 해당 이벤트를 필터링할 수 있습니다.

getPastEvents

myContract.getPastEvents(event [, options] [, callback])

이 컨트랙트의 이전 이벤트를 가져옵니다.

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 deployment. 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.

옵션 개체에는 다음이 포함됩니다:

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 on.

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. If given the filter property and event signature, topic[0] will not be set automatically.

Return Value

Promise returns Array: An array with the past event objects, matching the given event name and filter.

Example

> myContract.getPastEvents('MyEvent', {
      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: 'MyEvent',
    signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    logIndex: 0,
    transactionIndex: 0,
    transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
    blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    blockNumber: 1234,
    address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
},{
      ...
}]

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