> For the complete documentation index, see [llms.txt](https://archive-ko.docs.klaytn.foundation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://archive-ko.docs.klaytn.foundation/content/dapp/sdk/caver-js/v1.4.1/api-references/caver.utils_1.4.1.md).

# caver.utils (\~v1.4.1)

caver-js utility APIs.

`caver.utils` provides utility functions.

## randomHex <a href="#randomhex" id="randomhex"></a>

```javascript
caver.utils.randomHex(size)
```

The [randomHex](https://github.com/frozeman/randomHex) library to generate cryptographically strong pseudo-random HEX strings from a given byte size.

**Parameters**

| Name | Type   | Description                                                                     |
| ---- | ------ | ------------------------------------------------------------------------------- |
| size | Number | HEX 문자열의 바이트 크기, *가령*, `32`는 접두어 "0x"와 64개의 문자로 구성된 32바이트의 HEX 문자열이 결과가 될 것입니다. |

**Return Value**

| Type   | Description                      |
| ------ | -------------------------------- |
| String | The generated random HEX string. |

**Example**

```javascript
> caver.utils.randomHex(32);
"0xa5b9d60f32436310afebcfda832817a68921beb782fabf7915cc0460b443116a"

> caver.utils.randomHex(4);
"0x6892ffc6"

> caver.utils.randomHex(2);
"0x99d6"

> caver.utils.randomHex(1);
"0x9a"

> caver.utils.randomHex(0);
"0x"
```

## \_ <a href="#id" id="id"></a>

```javascript
caver.utils._()
```

많은 편리한 자바스크립트 함수를 위한 [underscore](http://underscorejs.org) 라이브러리.

See the [underscore API reference](http://underscorejs.org) for details.

**Example**

```javascript
> var _ = caver.utils._;

> _.union([1,2],[3]);
[1,2,3]

> _.each({my: 'object'}, function(value, key){ ... });
...
```

## BN <a href="#bn" id="bn"></a>

```javascript
caver.utils.BN(mixed)
```

자바스크립트에서 큰 수로 계산하기 위한 [BN.js](https://github.com/indutny/bn.js/) 라이브러리. 자세한 내용은 [BN.js documentation](https://github.com/indutny/bn.js/)을 참조하세요.

**Parameters**

| Name  | Type             | Description                          |
| ----- | ---------------- | ------------------------------------ |
| mixed | String \| Number | BN 객체로 변환할 숫자, 숫자 문자열 또는 HEX 문자열입니다. |

**Return Value**

| Type   | Description                                              |
| ------ | -------------------------------------------------------- |
| Object | The [BN.js](https://github.com/indutny/bn.js/) instance. |

**Example**

```javascript
> var BN = caver.utils.BN;

> new BN(1234).toString();
"1234"

> new BN('1234').add(new BN('1')).toString();
"1235"

> new BN('0xea').toString();
"234"
```

## isBN <a href="#isbn" id="isbn"></a>

```javascript
caver.utils.isBN(bn)
```

Checks if a given value is a [BN.js](https://github.com/indutny/bn.js/) instance.

**Parameters**

| Name | Type   | Description                                            |
| ---- | ------ | ------------------------------------------------------ |
| bn   | Object | A [BN.js](https://github.com/indutny/bn.js/) instance. |

**Return Value**

| Type    | Description                                                                       |
| ------- | --------------------------------------------------------------------------------- |
| Boolean | `true` if a given value is a [BN.js](https://github.com/indutny/bn.js/) instance. |

**Example**

```javascript
> var number = new BN(10);
> caver.utils.isBN(number);
true
```

## isBigNumber <a href="#isbignumber" id="isbignumber"></a>

```javascript
caver.utils.isBigNumber(bignumber)
```

Checks if a given value is a [BigNumber.js](http://mikemcl.github.io/bignumber.js/) instance.

**Parameters**

| Name      | Type   | Description                                                        |
| --------- | ------ | ------------------------------------------------------------------ |
| bignumber | Object | A [BigNumber.js](http://mikemcl.github.io/bignumber.js/) instance. |

**Return Value**

| Type    | Description                                           |
| ------- | ----------------------------------------------------- |
| Boolean | `true` if a given value is a `BigNumber.js` instance. |

**Example**

```javascript
> var number = new BigNumber(10);
> caver.utils.isBigNumber(number);
true
```

## sha3 <a href="#sha3" id="sha3"></a>

```javascript
caver.utils.sha3(string)
caver.utils.keccak256(string) // ALIAS
```

Calculates the sha3 of the input.

**참고**: 솔리디티의 sha3를 모방하려면 [caver.utils.soliditySha3](#soliditysha3)를 사용합니다.

**Parameters**

| Name   | Type   | Description       |
| ------ | ------ | ----------------- |
| string | String | A string to hash. |

**Return Value**

| Type   | Description      |
| ------ | ---------------- |
| String | The result hash. |

**Example**

```javascript
> caver.utils.sha3('234'); // taken as string
"0xc1912fee45d61c87cc5ea59dae311904cd86b84fee17cc96966216f811ce6a79"

> caver.utils.sha3(new BN('234')); // utils.sha3 stringify bignumber instance.
"0xc1912fee45d61c87cc5ea59dae311904cd86b84fee17cc96966216f811ce6a79"

> caver.utils.sha3(234);
null // can't calculate the has of a number

> caver.utils.sha3(0xea); // same as above, just the HEX representation of the number
null

> caver.utils.sha3('0xea'); // will be converted to a byte array first, and then hashed
"0x2f20677459120677484f7104c76deb6846a2c071f9b3152c103bb12cd54d1a4a"
```

## soliditySha3 <a href="#soliditysha3" id="soliditysha3"></a>

```javascript
caver.utils.soliditySha3(param1 [, param2, ...])
```

Calculates the sha3 of given input parameters in the same way solidity would. This means arguments will be ABI converted and tightly packed before being hashed.

**Parameters**

| Name   | Type  | Description                                                                                                                                                                                                                                                                    |
| ------ | ----- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| paramX | Mixed | <p>Any type, or an object with <code>{type: 'uint', value: '123456'}</code> or <code>{t: 'bytes', v: '0xfff456'}</code>. Basic types are autodetected as follows:<br>- <code>String</code> non numerical UTF-8 string is interpreted as <code>string</code>.<br>- \`String</p> |

**Return Value**

| Type   | Description      |
| ------ | ---------------- |
| String | The result hash. |

**Example**

```javascript
> caver.utils.soliditySha3('234564535', '0xfff23243', true, -10);
// auto detects: uint256, bytes, bool, int256
"0x3e27a893dc40ef8a7f0841d96639de2f58a132be5ae466d40087a2cfa83b7179"

> caver.utils.soliditySha3('Hello!%'); // auto detects: string
"0x661136a4267dba9ccdf6bfddb7c00e714de936674c4bdb065a531cf1cb15c7fc"

> caver.utils.soliditySha3('234'); // auto detects: uint256
"0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2"

> caver.utils.soliditySha3(0xea); // same as above
"0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2"

> caver.utils.soliditySha3(new BN('234')); // same as above
"0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2"

> caver.utils.soliditySha3({type: 'uint256', value: '234'})); // same as above
"0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2"

> caver.utils.soliditySha3({t: 'uint', v: new BN('234')})); // same as above
"0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2"

> caver.utils.soliditySha3('0x407D73d8a49eeb85D32Cf465507dd71d507100c1');
"0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b"

> caver.utils.soliditySha3({t: 'bytes', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'});
"0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b" // same result as above

> caver.utils.soliditySha3({t: 'address', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'});
"0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b" // same as above, but will do a checksum check, if its multi case

> caver.utils.soliditySha3({t: 'bytes32', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'});
"0x3c69a194aaf415ba5d6afca734660d0a3d45acdc05d54cd1ca89a8988e7625b4" // different result as above

> caver.utils.soliditySha3({t: 'string', v: 'Hello!%'}, {t: 'int8', v:-23}, {t: 'address', v: '0x85F43D8a49eeB85d32Cf465507DD71d507100C1d'});
"0xa13b31627c1ed7aaded5aecec71baf02fe123797fffd45e662eac8e06fbe4955"
```

## isHex <a href="#ishex" id="ishex"></a>

```javascript
caver.utils.isHex(hex)
```

Checks if a given string is a HEX string.

**Parameters**

| Name | Type          | Description           |
| ---- | ------------- | --------------------- |
| hex  | String \| HEX | The given HEX string. |

**Return Value**

| Type    | Description                               |
| ------- | ----------------------------------------- |
| Boolean | `true` if a given string is a HEX string. |

**Example**

```javascript
> caver.utils.isHex('0xc1912');
true

> caver.utils.isHex(0xc1912);
true

> caver.utils.isHex('c1912');
true

> caver.utils.isHex(345);
true // this is tricky, as 345 can be a HEX representation or a number, be careful when not having a 0x in front!

> caver.utils.isHex('0xZ1912');
false

> caver.utils.isHex('Hello');
false
```

## isHexStrict <a href="#ishexstrict" id="ishexstrict"></a>

```javascript
caver.utils.isHexStrict(hex)
```

Checks if a given string is a HEX string. [caver.utils.isHex](#ishex)와의 차이점은 HEX 앞에 `0x`이 붙는다는 것입니다.

**Parameters**

| Name | Type          | Description           |
| ---- | ------------- | --------------------- |
| hex  | String \| HEX | The given HEX string. |

**Return Value**

| Type    | Description                               |
| ------- | ----------------------------------------- |
| Boolean | `true` if a given string is a HEX string. |

**Example**

```javascript
> caver.utils.isHexStrict('0xc1912');
true

> caver.utils.isHexStrict(0xc1912);
false

> caver.utils.isHexStrict('c1912');
false

> caver.utils.isHexStrict(345);
false // this is tricky, as 345 can be a HEX representation or a number, be careful when not having a 0x in front!

> caver.utils.isHexStrict('0xZ1912');
false

> caver.utils.isHex('Hello');
false
```

## isAddress <a href="#isaddress" id="isaddress"></a>

```javascript
caver.utils.isAddress(address)
```

Checks if a given string is a valid Klaytn address. 주소에 대문자와 소문자가 있으면 체크섬(checksum)도 검사합니다.

**Parameters**

| Name    | Type   | Description        |
| ------- | ------ | ------------------ |
| address | String | An address string. |

**Return Value**

| Type    | Description                                         |
| ------- | --------------------------------------------------- |
| Boolean | `true` if a given string is a valid Klaytn address. |

**Examples**

```javascript
> caver.utils.isAddress('0xc1912fee45d61c87cc5ea59dae31190fffff232d');
true

> caver.utils.isAddress('c1912fee45d61c87cc5ea59dae31190fffff232d');
true

> caver.utils.isAddress('0XC1912FEE45D61C87CC5EA59DAE31190FFFFF232D');
true // as all is uppercase, no checksum will be checked

> caver.utils.isAddress('0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d');
true

> caver.utils.isAddress('0xC1912fEE45d61C87Cc5EA59DaE31190FFFFf232d');
false // wrong checksum
```

## toChecksumAddress <a href="#tochecksumaddress" id="tochecksumaddress"></a>

```javascript
caver.utils.toChecksumAddress(address)
```

Converts an upper or lowercase Klaytn address to a checksum address.

**Parameters**

| Name    | Type   | Description        |
| ------- | ------ | ------------------ |
| address | String | An address string. |

**Return Value**

| Type   | Description           |
| ------ | --------------------- |
| String | The checksum address. |

**Examples**

```javascript
> caver.utils.toChecksumAddress('0xc1912fee45d61c87cc5ea59dae31190fffff232d');
"0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d"

> caver.utils.toChecksumAddress('0XC1912FEE45D61C87CC5EA59DAE31190FFFFF232D');
"0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d" // same as above
```

## checkAddressChecksum <a href="#checkaddresschecksum" id="checkaddresschecksum"></a>

```javascript
caver.utils.checkAddressChecksum(address)
```

Checks the checksum of a given address. Will also return `false` on non-checksum addresses.

**Parameters**

| Name    | Type   | Description        |
| ------- | ------ | ------------------ |
| address | String | An address string. |

**Return Value**

| Type    | Description                                                                                                            |
| ------- | ---------------------------------------------------------------------------------------------------------------------- |
| Boolean | `true` when the checksum of the address is valid, `false` if it is not a checksum address, or the checksum is invalid. |

**Examples**

```javascript
> caver.utils.checkAddressChecksum('0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d');
true
```

## toHex <a href="#tohex" id="tohex"></a>

```javascript
caver.utils.toHex(mixed)
```

Converts any given value to HEX. 숫자 문자열은 숫자로 해석됩니다. Text strings will be interpreted as UTF-8 strings.

**Parameters**

| Name  | Type                                | Description   |
| ----- | ----------------------------------- | ------------- |
| mixed | String \| Number \| BN \| BigNumber | HEX로 변환할 입력값. |

**Return Value**

| Type   | Description               |
| ------ | ------------------------- |
| String | The resulting HEX string. |

**Examples**

```javascript
> caver.utils.toHex('234');
"0xea"

> caver.utils.toHex(234);
"0xea"

> caver.utils.toHex(new BN('234'));
"0xea"

> caver.utils.toHex(new BigNumber('234'));
"0xea"

> caver.utils.toHex('I have 100€');
"0x49206861766520313030e282ac"
```

## toBN <a href="#tobn" id="tobn"></a>

```javascript
caver.utils.toBN(number)
```

Safely converts any given value (including [BigNumber.js](http://mikemcl.github.io/bignumber.js/) instances) into a [BN.js](https://github.com/indutny/bn.js/) instance, for handling big numbers in JavaScript.

**참고**: [BN.js](https://github.com/indutny/bn.js/) 클래스의 경우 [caver.utils.BN](#bn)를 사용합니다.

**Parameters**

| Name   | Type                    | Description   |
| ------ | ----------------------- | ------------- |
| number | String \| Number \| HEX | 큰 숫자로 변환할 숫자. |

**Return Value**

| Type   | Description                                              |
| ------ | -------------------------------------------------------- |
| Object | The [BN.js](https://github.com/indutny/bn.js/) instance. |

**Examples**

```javascript
> caver.utils.toBN(1234).toString();
"1234"

> caver.utils.toBN('1234').add(caver.utils.toBN('1')).toString();
"1235"

> caver.utils.toBN('0xea').toString();
"234"
```

## hexToNumberString <a href="#hextonumberstring" id="hextonumberstring"></a>

```javascript
caver.utils.hexToNumberString(hex)
```

Returns the number representation of a given HEX value as a string.

**Parameters**

| Name      | Type       | Description                   |
| --------- | ---------- | ----------------------------- |
| hexString | HEX String | A HEX string to be converted. |

**Return Value**

| Type   | Description             |
| ------ | ----------------------- |
| String | The number as a string. |

**Examples**

```javascript
> caver.utils.hexToNumberString('0xea');
"234"
```

## hexToNumber <a href="#hextonumber" id="hextonumber"></a>

```javascript
caver.utils.hexToNumber(hex)
```

Returns the number representation of a given HEX value.

**참고**: 큰 숫자에는 유용하지 않으며, [caver.utils.toBN](#tobn)를 대신 사용합니다.

**Parameters**

| Name      | Type       | Description                   |
| --------- | ---------- | ----------------------------- |
| hexString | HEX String | A HEX string to be converted. |

**Return Value**

| Type   | Description                                     |
| ------ | ----------------------------------------------- |
| Number | The number representation of a given HEX value. |

**Examples**

```javascript
> caver.utils.hexToNumber('0xea');
234
```

## numberToHex <a href="#numbertohex" id="numbertohex"></a>

```javascript
caver.utils.numberToHex(number)
```

Returns the HEX representation of a given number value.

**Parameters**

| Name   | Type                                | Description      |
| ------ | ----------------------------------- | ---------------- |
| number | String \| Number \| BN \| BigNumber | 문자열 또는 숫자로 된 숫자. |

**Return Value**

| Type   | Description                        |
| ------ | ---------------------------------- |
| String | The HEX value of the given number. |

**Examples**

```javascript
> caver.utils.numberToHex('234');
'0xea'
```

## hexToUtf8 <a href="#hextoutf8" id="hextoutf8"></a>

```javascript
caver.utils.hexToUtf8(hex)
caver.utils.hexToString(hex) // ALIAS
```

Returns the UTF-8 string representation of a given HEX value.

**Parameters**

| Name | Type   | Description                                |
| ---- | ------ | ------------------------------------------ |
| hex  | String | A HEX string to convert to a UTF-8 string. |

**Return Value**

| Type   | Description       |
| ------ | ----------------- |
| String | The UTF-8 string. |

**Examples**

```javascript
> caver.utils.hexToUtf8('0x49206861766520313030e282ac');
"I have 100€"
```

## hexToAscii <a href="#hextoascii" id="hextoascii"></a>

```javascript
caver.utils.hexToAscii(hex)
```

Returns the ASCII string representation of a given HEX value.

**Parameters**

| Name | Type   | Description             |
| ---- | ------ | ----------------------- |
| hex  | String | ASCII 문자열로 변환할 HEX 문자열. |

**Return Value**

| Type   | Description       |
| ------ | ----------------- |
| String | The ASCII string. |

**Examples**

```javascript
> caver.utils.hexToAscii('0x4920686176652031303021');
"I have 100!"
```

## utf8ToHex <a href="#utf8tohex" id="utf8tohex"></a>

```javascript
caver.utils.utf8ToHex(string)
caver.utils.stringToHex(string) // ALIAS
```

Returns the HEX representation of a given UTF-8 string.

**Parameters**

| Name   | Type   | Description                                |
| ------ | ------ | ------------------------------------------ |
| string | String | A UTF-8 string to convert to a HEX string. |

**Return Value**

| Type   | Description     |
| ------ | --------------- |
| String | The HEX string. |

**Examples**

```javascript
> caver.utils.utf8ToHex('I have 100€');
"0x49206861766520313030e282ac"
```

## asciiToHex <a href="#asciitohex" id="asciitohex"></a>

```javascript
caver.utils.asciiToHex(string)
```

Returns the HEX representation of a given ASCII string.

**Parameters**

| Name   | Type   | Description                                 |
| ------ | ------ | ------------------------------------------- |
| string | String | An ASCII string to convert to a HEX string. |

**Return Value**

| Type   | Description     |
| ------ | --------------- |
| String | The HEX string. |

**Examples**

```javascript
> caver.utils.asciiToHex('I have 100!');
"0x4920686176652031303021"
```

## hexToBytes <a href="#hextobytes" id="hextobytes"></a>

```javascript
caver.utils.hexToBytes(hex)
```

Returns a byte array from the given HEX string.

**Parameters**

| Name | Type       | Description                   |
| ---- | ---------- | ----------------------------- |
| hex  | HEX String | A HEX string to be converted. |

**Return Value**

| Type  | Description     |
| ----- | --------------- |
| Array | The byte array. |

**Examples**

```javascript
> caver.utils.hexToBytes('0x000000ea');
[ 0, 0, 0, 234 ]
```

## bytesToHex <a href="#bytestohex" id="bytestohex"></a>

```javascript
caver.utils.bytesToHex(byteArray)
```

Returns a HEX string from a byte array.

**Parameters**

| Name      | Type  | Description              |
| --------- | ----- | ------------------------ |
| byteArray | Array | A byte array to convert. |

**Return Value**

| Type   | Description     |
| ------ | --------------- |
| String | The HEX string. |

**Examples**

```javascript
> caver.utils.bytesToHex([ 72, 101, 108, 108, 111, 33, 36 ]);
"0x48656c6c6f2125"
```

## toPeb <a href="#topeb" id="topeb"></a>

```javascript
caver.utils.toPeb(number [, unit])
```

Converts any KLAY value into peb.

**참고**: "peb"는 가장 작은 KLAY 단위이며, 항상 peb로 계산해야 하며 표시할 용도로만 변환해야 합니다.

**Parameters**

| Name   | Type                   | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| ------ | ---------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| number | String \| Number \| BN | 값.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| unit   | String                 | <p>(선택 사항, 기본값은 <code>"KLAY"</code>) 변환하려고 하는 KLAY. Possible units are:<br>- <code>peb</code>: '1'<br>- <code>kpeb</code>: '1000'<br>- <code>Mpeb</code>: '1000000'<br>- <code>Gpeb</code>: '1000000000'<br>- <code>Ston</code>: '1000000000'<br>- <code>uKLAY</code>: '1000000000000'<br>- <code>mKLAY</code>: '1000000000000000'<br>- <code>KLAY</code>: '1000000000000000000'<br>- <code>kKLAY</code>: '1000000000000000000000'<br>- <code>MKLAY</code>: '1000000000000000000000000'<br>- <code>GKLAY</code>: '1000000000000000000000000000'<br></p> |

**Return Value**

| Type         | Description                                                                                   |
| ------------ | --------------------------------------------------------------------------------------------- |
| String \| BN | 숫자 또는 문자열이 주어지면 숫자 문자열을 반환하고, 그렇지 않으면 [BN.js](https://github.com/indutny/bn.js/) 인스턴스를 반환합니다. |

**Examples**

```javascript
> caver.utils.toPeb('1', 'KLAY');
"1000000000000000000"
```

## fromPeb <a href="#frompeb" id="frompeb"></a>

```javascript
caver.utils.fromPeb(number [, unit])
```

**참고**: "peb"는 가장 작은 KLAY 단위이며, 항상 peb로 계산해야 하며 표시할 용도로만 변환해야 합니다.

**Parameters**

| Name   | Type                   | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| ------ | ---------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| number | String \| Number \| BN | peb 단위의 값.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| unit   | String                 | <p>(선택 사항, 기본값은 <code>"KLAY"</code>) 변환하고자 하는 KLAY. Possible units are:<br>- <code>peb</code>: '1'<br>- <code>kpeb</code>: '1000'<br>- <code>Mpeb</code>: '1000000'<br>- <code>Gpeb</code>: '1000000000'<br>- <code>Ston</code>: '1000000000'<br>- <code>uKLAY</code>: '1000000000000'<br>- <code>mKLAY</code>: '1000000000000000'<br>- <code>KLAY</code>: '1000000000000000000'<br>- <code>kKLAY</code>: '1000000000000000000000'<br>- <code>MKLAY</code>: '1000000000000000000000000'<br>- <code>GKLAY</code>: '1000000000000000000000000000'<br></p> |

**Return Value**

| Type         | Description                                                                                                                    |
| ------------ | ------------------------------------------------------------------------------------------------------------------------------ |
| String \| BN | If a number or a string is given, it returns a number string, otherwise a [BN.js](https://github.com/indutny/bn.js/) instance. |

**Examples**

```javascript
> caver.utils.fromPeb('1', 'KLAY');
"0.000000000000000001"
```

## unitMap <a href="#unitmap" id="unitmap"></a>

```javascript
caver.utils.unitMap
```

Shows all possible KLAY values and their amount in peb.

**Return Value**

| Type   | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| ------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Object | <p>With the following properties:<br>- <code>peb</code>: '1'<br>- <code>kpeb</code>: '1000'<br>- <code>Mpeb</code>: '1000000'<br>- <code>Gpeb</code>: '1000000000'<br>- <code>Ston</code>: '1000000000'<br>- <code>uKLAY</code>: '1000000000000'<br>- <code>mKLAY</code>: '1000000000000000'<br>- <code>KLAY</code>: '1000000000000000000'<br>- <code>kKLAY</code>: '1000000000000000000000'<br>- <code>MKLAY</code>: '1000000000000000000000000'<br>- <code>GKLAY</code>: '1000000000000000000000000000'<br></p> |

**Examples**

```javascript
> caver.utils.unitMap


{
  peb: '1',
  kpeb: '1000',
  Mpeb: '1000000',
  Gpeb: '1000000000',
  Ston: '1000000000',
  uKLAY: '1000000000000',
  mKLAY: '1000000000000000',
  KLAY: '1000000000000000000',
  kKLAY: '1000000000000000000000',
  MKLAY: '1000000000000000000000000',
  GKLAY: '1000000000000000000000000000',
}
```

## padLeft <a href="#padleft" id="padleft"></a>

```javascript
caver.utils.padLeft(string, characterAmount [, sign])
caver.utils.leftPad(string, characterAmount [, sign]) // ALIAS
```

문자열 왼쪽에 패딩(padding)을 추가합니다. Useful for adding paddings to HEX strings.

**Parameters**

| Name            | Type   | Description                                            |
| --------------- | ------ | ------------------------------------------------------ |
| string          | String | The string to add padding on the left.                 |
| characterAmount | Number | The number of characters the total string should have. |
| sign            | String | (선택 사항) 사용할 문자 부호, 기본값은 `"0"`.                         |

**Return Value**

| Type   | Description        |
| ------ | ------------------ |
| String | The padded string. |

**Examples**

```javascript
> caver.utils.padLeft('0x3456ff', 20);
"0x000000000000003456ff"

> caver.utils.padLeft(0x3456ff, 20);
"0x000000000000003456ff"

> caver.utils.padLeft('Hello', 20, 'x');
"xxxxxxxxxxxxxxxHello"
```

## padRight <a href="#padright" id="padright"></a>

```javascript
caver.utils.padRight(string, characterAmount [, sign])
caver.utils.rightPad(string, characterAmount [, sign]) // ALIAS
```

문자열 오른쪽에 패딩을 추가합니다. HEX 문자열에 패딩을 추가하는 데 유용합니다.

**Parameters**

| Name            | Type   | Description                                              |
| --------------- | ------ | -------------------------------------------------------- |
| string          | String | The string to add padding on the right.                  |
| characterAmount | Number | The number of characters the total string should have.   |
| sign            | String | (optional) The character sign to use, defaults to `"0"`. |

**Return Value**

| Type   | Description        |
| ------ | ------------------ |
| String | The padded string. |

**Examples**

```javascript
> caver.utils.padRight('0x3456ff', 20);
"0x3456ff00000000000000"

> caver.utils.padRight(0x3456ff, 20);
"0x3456ff00000000000000"

> caver.utils.padRight('Hello', 20, 'x');
"Helloxxxxxxxxxxxxxxx"
```

## toTwosComplement <a href="#totwoscomplement" id="totwoscomplement"></a>

```javascript
caver.utils.toTwosComplement(number)
```

Converts a negative number into a two's complement.

**Parameters**

| Name   | Type                          | Description |
| ------ | ----------------------------- | ----------- |
| number | Number \| String \| BigNumber | 변환할 숫자.     |

**Return Value**

| Type   | Description               |
| ------ | ------------------------- |
| String | The converted hex string. |

**Examples**

```javascript
> caver.utils.toTwosComplement('-1');
"0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"

> caver.utils.toTwosComplement(-1);
"0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"

> caver.utils.toTwosComplement('0x1');
"0x0000000000000000000000000000000000000000000000000000000000000001"

> caver.utils.toTwosComplement(-15);
"0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff1"

> caver.utils.toTwosComplement('-0x1');
"0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
```

## isContractDeployment <a href="#iscontractdeployment" id="iscontractdeployment"></a>

```javascript
caver.utils.isContractDeployment(transactionObject)
```

Returns `true` if the given transaction is a smart contract deploy transaction. It returns `false` if the transaction is not a smart contract deploy transaction. The result is determined by the values of the parameters in the `transactionObject`. Make sure all the mandatory parameters are set correctly.

**참고** caver.klay.isContractDeployment는 **v1.0.1-rc.8**에서 지원됩니다. To use this feature, please install [v1.0.1-rc.8](https://www.npmjs.com/package/caver-js/v/1.0.1-rc.8) or higher.

**Parameters**

| Name              | Type   | Description                                 |
| ----------------- | ------ | ------------------------------------------- |
| transactionObject | Object | 트랜잭션이 스마트 컨트랙트 배포용인지 사용자가 확인하고자 하는 트랜잭션 객체. |

**Return Value**

| Type    | Description                                                       |
| ------- | ----------------------------------------------------------------- |
| Boolean | `true` means the transaction object is for smart contract deploy. |

**Examples**

```javascript
> caver.utils.isContractDeployment({
    type: 'SMART_CONTRACT_DEPLOY',
    from: '0x90B3E9A3770481345A7F17f22f16D020Bccfd33e',
    nonce: '0x8',
    data:  '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',
    gas: '0x3b9ac9ff',
    gasPrice: '0x5d21dba00',
    value: '0x0',
    chainId: '0x1',
})
true

> caver.utils.isContractDeployment({
    type: 'LEGACY',
    from: '0x90B3E9A3770481345A7F17f22f16D020Bccfd33e',
    data:  '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',
    gas: '0x3b9ac9ff',
})
true

> caver.utils.isContractDeployment({
    from: '0x90B3E9A3770481345A7F17f22f16D020Bccfd33e',
    data:  '0x608060405234801561001057600080fd5b506101de806100206000396000f3006080604052600436106100615763ffffffff7c01000000000000000000000000000000000000000000000000000000006000350416631a39d8ef81146100805780636353586b146100a757806370a08231146100ca578063fd6b7ef8146100f8575b3360009081526001602052604081208054349081019091558154019055005b34801561008c57600080fd5b5061009561010d565b60408051918252519081900360200190f35b6100c873ffffffffffffffffffffffffffffffffffffffff60043516610113565b005b3480156100d657600080fd5b5061009573ffffffffffffffffffffffffffffffffffffffff60043516610147565b34801561010457600080fd5b506100c8610159565b60005481565b73ffffffffffffffffffffffffffffffffffffffff1660009081526001602052604081208054349081019091558154019055565b60016020526000908152604090205481565b336000908152600160205260408120805490829055908111156101af57604051339082156108fc029083906000818181858888f193505050501561019c576101af565b3360009081526001602052604090208190555b505600a165627a7a72305820627ca46bb09478a015762806cc00c431230501118c7c26c30ac58c4e09e51c4f0029',
    gas: '0x3b9ac9ff',
})
true

> caver.utils.isContractDeployment({
    type: 'ACCOUNT_UPDATE',
    from: '0x88e245dec96830f012f8fc1806bc623b3774560d',
    publicKey: '0x4ef27ba4b7d1ae09b166744c5b7ee4a7a0cc5c76b2e5d74523a0a4fb56db319162ff3255302045cd047a27141916d55615a7c1ead06e211e62119e7bc2a40def',
    nonce: '0x0',
    gas: '0x3b9ac9ff',
    chainId: '0x7e3',
    gasPrice: '0x5d21dba00',
})
false
```

## xyPointFromPublicKey <a href="#xypointfrompublickey" id="xypointfrompublickey"></a>

```javascript
caver.utils.xyPointFromPublicKey(publicKey)
```

Returns the x and y coordinates of the given publicKey. 키 암호화에 대한 자세한 내용은 [타원 곡선 암호화](https://en.wikipedia.org/wiki/Elliptic-curve_cryptography)를 참조하세요.

**NOTE** This function does not contain any logic to check whether the public key is valid. The function only split the input publicKey into x and y points by length.

**Parameters**

| Name      | Type   | Description                          |
| --------- | ------ | ------------------------------------ |
| publicKey | String | The publicKey to get x and y points. |

**Return Value**

| Type  | Description                                                                    |
| ----- | ------------------------------------------------------------------------------ |
| Array | An array storing x and y points. Index 0 has x point, and index 1 has y point. |

**Examples**

```javascript
> caver.utils.xyPointFromPublicKey('0xa5862ded55cd9c7e9ff246dbc264ca5d5c605308f59b74e581b4f089d4c8c88cb9f00df6a56493f6029af215d266c907660ea0f7a4111ea025ea9d9be418fa55')
[ 
    '0xa5862ded55cd9c7e9ff246dbc264ca5d5c605308f59b74e581b4f089d4c8c88c',
    '0xb9f00df6a56493f6029af215d266c907660ea0f7a4111ea025ea9d9be418fa55'
]
```

## isHexPrefixed <a href="#ishexprefixed" id="ishexprefixed"></a>

```javascript
caver.utils.isHexPrefixed(input)
```

입력이 0x 접두사가 있는 16진수 문자열이면 `true`, 그렇지 않으면 `false`를 반환합니다.

**참고** caver.klay.isHexPrefixed는 **v1.0.1**에서 지원됩니다. To use this feature, please install [v1.0.1](https://www.npmjs.com/package/caver-js/v/1.0.1) or higher.

**Parameters**

| Name  | Type   | Description                                                                   |
| ----- | ------ | ----------------------------------------------------------------------------- |
| input | String | The value to be determined if the parameter is 0x-prefixed hex string or not. |

**Return Value**

| Type    | Description                                       |
| ------- | ------------------------------------------------- |
| Boolean | `true` means the input is 0x-prefixed hex string. |

**Examples**

```javascript
> caver.utils.isHexPrefixed('0xa5b0cd8c87e77879d64cc064ee239ed6f71cacf9')
true

> caver.utils.isHexPrefixed('0x1')
true

> caver.utils.isHexPrefixed('0xqwer')
false

> caver.utils.isHexPrefixed('1')
false
```

## addHexPrefix <a href="#addhexprefix" id="addhexprefix"></a>

```javascript
caver.utils.addHexPrefix(input)
```

Returns a 0x-prefixed hex string. If the input is already 0x-prefixed or a non-hex string, the input value is returned as-is.

**참고** caver.klay.addHexPrefix는 **v1.0.1**에서 지원됩니다. To use this feature, please install [v1.0.1](https://www.npmjs.com/package/caver-js/v/1.0.1) or higher.

**Parameters**

| Name  | Type   | Description       |
| ----- | ------ | ----------------- |
| input | String | 0x 접두사를 더할 문자열 값. |

**Return Value**

| Type   | Description                         |
| ------ | ----------------------------------- |
| String | 0x-prefixed hex string is returned. |

**Examples**

```javascript
> caver.utils.addHexPrefix('a5b0cd8c87e77879d64cc064ee239ed6f71cacf9')
'0xa5b0cd8c87e77879d64cc064ee239ed6f71cacf9'

> caver.utils.addHexPrefix('0xa5b0cd8c87e77879d64cc064ee239ed6f71cacf9')
'0xa5b0cd8c87e77879d64cc064ee239ed6f71cacf9'
```

## stripHexPrefix <a href="#striphexprefix" id="striphexprefix"></a>

```javascript
caver.utils.stripHexPrefix(input)
```

Returns the result with 0x prefix stripped from input.

**NOTE** caver.klay.stripHexPrefix is supported from **v1.0.1**. To use this feature, please install [v1.0.1](https://www.npmjs.com/package/caver-js/v/1.0.1) or higher.

**Parameters**

| Name  | Type   | Description      |
| ----- | ------ | ---------------- |
| input | String | 접두사 0x를 제거할 문자열. |

**Return Value**

| Type   | Description                          |
| ------ | ------------------------------------ |
| String | A string stripped of 0x is returned. |

**Examples**

```javascript
> caver.utils.stripHexPrefix('a5b0cd8c87e77879d64cc064ee239ed6f71cacf9')
'a5b0cd8c87e77879d64cc064ee239ed6f71cacf9'

> caver.utils.stripHexPrefix('0xa5b0cd8c87e77879d64cc064ee239ed6f71cacf9')
'a5b0cd8c87e77879d64cc064ee239ed6f71cacf9'
```

## toBuffer <a href="#tobuffer" id="tobuffer"></a>

```javascript
caver.utils.toBuffer(input)
```

This function converts the input to a [Buffer](https://nodejs.org/api/buffer.html). `toBuffer`을 사용하여 객체를 버퍼로 변환하려면, 객체는 반드시 **toArray** 함수를 구현해야 합니다. 문자열 유형 입력의 경우, 이 함수는 **0x 접두사가 있는 16진수 문자열**에서만 작동합니다.

**참고** caver.klay.toBuffer는 **v1.1.0**에서 지원됩니다. 이 기능을 사용하려면 [v1.1.0](https://www.npmjs.com/package/caver-js/v/1.1.0) 또는 그 이상을 설치하세요.

**Parameters**

| Name  | Type                                                | Description |
| ----- | --------------------------------------------------- | ----------- |
| input | Buffer \| String \| Number \| Array \| BN \| Object | 버퍼로 변환할 값.  |

**Return Value**

| Type   | Description                                     |
| ------ | ----------------------------------------------- |
| Buffer | The value converted to Buffer type is returned. |

**Examples**

```javascript
// Buffer
> caver.utils.toBuffer(Buffer.alloc(0))
<Buffer >
// 0x-prefixed hex string
> caver.utils.toBuffer('0x1234')
<Buffer 12 34>
// Number
> caver.utils.toBuffer(1)
<Buffer 01>
// Array
> caver.utils.toBuffer([1,2,3])
<Buffer 01 02 03>
// BN
> caver.utils.toBuffer(new caver.utils.BN(255))
<Buffer ff>
// Object that implements toArray function
> caver.utils.toBuffer({toArray: function() {return [1,2,3,4]}})
<Buffer 01 02 03 04>
// null or undefined
> caver.utils.toBuffer(null)
<Buffer >
> caver.utils.toBuffer(undefined)
<Buffer >
// non 0x-prefixed hex string
> caver.utils.toBuffer('0xqwer')
Error: Failed to convert string to Buffer. 'toBuffer' function only supports 0x-prefixed hex string
// Object that does not implement toArray function
> caver.utils.toBuffer({})
Error: To convert an object to a buffer, the toArray function must be implemented inside the object
```

## numberToBuffer <a href="#numbertobuffer" id="numbertobuffer"></a>

```javascript
caver.utils.numberToBuffer(input)
```

This function converts a number to a [Buffer](https://nodejs.org/api/buffer.html). 입력이 숫자인 경우 [caver.utils.toBuffer](#tobuffer)는 이 함수와 동일하게 동작합니다.

**참고** caver.klay.numberToBuffer는 **v1.1.0**에서 지원됩니다. To use this feature, please install [v1.1.0](https://www.npmjs.com/package/caver-js/v/1.1.0) or higher.

**Parameters**

| Name  | Type                   | Description |
| ----- | ---------------------- | ----------- |
| input | String \| Number \| BN | 버퍼로 변환할 숫자. |

**Return Value**

| Type   | Description                                     |
| ------ | ----------------------------------------------- |
| Buffer | The value converted to Buffer type is returned. |

**Examples**

```javascript
> caver.utils.numberToBuffer(1)
<Buffer 01>
> caver.utils.numberToBuffer('2')
<Buffer 02>
> caver.utils.numberToBuffer('0x3')
<Buffer 03>
> caver.utils.numberToBuffer(new caver.utils.BN(4))
<Buffer 04>
```

## isTxHash <a href="#istxhash" id="istxhash"></a>

```javascript
caver.utils.isTxHash(input)
```

입력이 트랜잭션 해시 형식이면 `true`, 그렇지 않으면 `false`를 반환합니다. This function only looks at the input and determines if it is in the format of a transaction hash. **참고** caver.klay.isTxHash는 **v1.2.0-rc.1**에서 지원됩니다. 이 기능을 사용하려면 [v1.2.0-rc.1](https://www.npmjs.com/package/caver-js/v/1.2.0-rc.1) 또는 그 이상을 설치하세요. **매개변수**

| Name  | Type   | Description                                                                              |
| ----- | ------ | ---------------------------------------------------------------------------------------- |
| input | String | The value to be determined if the parameter is in the format of transaction hash or not. |

**Return Value**

| Type    | Description                      |
| ------- | -------------------------------- |
| Boolean | `true`는 입력값이 트랜잭션 해시 형식임을 의미합니다. |

**Examples**

```javascript
// with '0x' hex prefix
> caver.utils.isTxHash('0xe9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')
true
// without '0x' hex prefix
> caver.utils.isTxHash('e9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')
true
> caver.utils.isTxHash('0x1')
false
```

## isTxHashStrict <a href="#istxhashstrict" id="istxhashstrict"></a>

```javascript
caver.utils.isTxHashStrict(input)
```

Returns `true` if input is in transaction hash format, otherwise it returns `false`. This function only looks at the input and determines if it is in the format of a transaction hash. [caver.utils.isTxHash](#istxhash)와의 차이점은 HEX 앞에 `0x`이 붙는다는 것입니다. **참고** caver.klay.isTxHashStrict는 **v1.2.0-rc.1**에서 지원됩니다. To use this feature, please install [v1.2.0-rc.1](https://www.npmjs.com/package/caver-js/v/1.2.0-rc.1) or higher. **Parameters**

| Name  | Type   | Description                                                                              |
| ----- | ------ | ---------------------------------------------------------------------------------------- |
| input | String | The value to be determined if the parameter is in the format of transaction hash or not. |

**Return Value**

| Type    | Description                                                  |
| ------- | ------------------------------------------------------------ |
| Boolean | `true` means the input is in the format of transaction hash. |

**Examples**

```javascript
// with '0x' hex prefix
> caver.utils.isTxHashStrict('0xe9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')
true
// without '0x' hex prefix
> caver.utils.isTxHashStrict('e9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')
false
> caver.utils.isTxHashStrict('0x1')
false
```

## isValidPrivateKey <a href="#isvalidprivatekey" id="isvalidprivatekey"></a>

```javascript
caver.utils.isValidPrivateKey(privateKey)
```

privateKey가 유효하면 `true`, 그렇지 않으면 `false`리턴합니다.

**Parameters**

| Name       | Type   | Description                       |
| ---------- | ------ | --------------------------------- |
| privateKey | String | A private key string to validate. |

**Return Value**

| Type    | Description                           |
| ------- | ------------------------------------- |
| Boolean | `true` means the privateKey is valid. |

**Examples**

```javascript
> caver.utils.isValidPrivateKey('0x{private key}')
true

> caver.utils.isValidPrivateKey('{private key}')
true

> caver.utils.isValidPrivateKey('a5b0cd8c87e77879d64cc064ee239ed6f71cacf9')
false
```

## isValidPublicKey <a href="#isvalidpublickey" id="isvalidpublickey"></a>

```javascript
caver.utils.isValidPublicKey(publicKey)
```

Returns `true` if publicKey is valid, otherwise it returns `false`.

**참고** `caver.utils.isValidPublicKey`는 caver-js [v1.2.0](https://www.npmjs.com/package/caver-js/v/1.2.0)부터 지원됩니다.

**Parameters**

| Name      | Type   | Description                      |
| --------- | ------ | -------------------------------- |
| publicKey | String | A public key string to validate. |

**Return Value**

| Type    | Description                          |
| ------- | ------------------------------------ |
| Boolean | `true` means the publicKey is valid. |

**Examples**

```javascript
// validation with uncompressed public key
> caver.utils.isValidPublicKey('0xbd6405a7f14f57ecea4a6ffe774ee26d051f7eed13257c9a574055b20e42bab0e8beba92e2e675101eb2a55ba4693080d0bf14548beae7bc93b18b72d10dd350')
true

// validation with compressed public key
> caver.utils.isValidPublicKey('0x02bd6405a7f14f57ecea4a6ffe774ee26d051f7eed13257c9a574055b20e42bab0')
true

> caver.utils.isValidPublicKey('{private key}')
false

> caver.utils.isValidPublicKey('0x{private key}')
false

> caver.utils.isValidPublicKey('a5b0cd8c87e77879d64cc064ee239ed6f71cacf9')
false
```

## isValidRole <a href="#isvalidrole" id="isvalidrole"></a>

```javascript
caver.utils.isValidRole(role)
```

role이 유효하면 `true`, 그렇지 않으면 `false`를 반환합니다. AccountKeyRoleBased에서 사용되는 현재 정의된 role은 `transactionKey`,`updateKey`및 `feePayerKey`입니다.

**참고** `caver.utils.isValidRole`는 caver-js [v1.2.0](https://www.npmjs.com/package/caver-js/v/1.2.0)부터 지원됩니다.

**Parameters**

| Name | Type   | Description                |
| ---- | ------ | -------------------------- |
| role | String | A role string to validate. |

**Return Value**

| Type    | Description                     |
| ------- | ------------------------------- |
| Boolean | `true` means the role is valid. |

**Examples**

```javascript
> caver.utils.isValidRole('transactionKey')
true

> caver.utils.isValidRole('updateKey')
true

> caver.utils.isValidRole('feePayerKey')
true

> caver.utils.isValidRole('role')
false
```

## isEmptySig <a href="#isemptysig" id="isemptysig"></a>

```javascript
caver.utils.isEmptySig(sig)
```

sig가 빈 서명 형식인 경우 (`[[ '0x01', '0x', '0x']]` 또는 `[ '0x01', '0x', '0x']`) `true`, 그렇지 않은 경우 `false`를 반환합니다.

caver-js에서 트랜잭션을 RLP 인코딩할 때 signatures 또는 feePayerSignatures가 비어있는 경우, 해당 프로퍼티에는 빈 서명을 나타내는 `[[ '0x01', '0x', '0x']]` 값이 반환됩니다. 이 함수는 주어진 서명이 `[[ '0x01', '0x', '0x']]`인지 ('legacy' 트랜잭션인 경우는 `[ '0x01', '0x', '0x']`) 확인하고자 할 때 사용합니다.

**참고** `caver.utils.isEmptySig`는 caver-js [v1.2.0](https://www.npmjs.com/package/caver-js/v/1.2.0)부터 지원됩니다.

**Parameters**

| Name | Type  | Description       |
| ---- | ----- | ----------------- |
| sig  | Array | 비어있는지 확인할 서명의 배열. |

**Return Value**

| Type    | Description                                                                |
| ------- | -------------------------------------------------------------------------- |
| Boolean | `true`는 sig가 `[[ '0x01', '0x', '0x']]` 또는 `[ '0x01', '0x', '0x']`임을 의미합니다. |

**Examples**

```javascript
> caver.utils.isEmptySig([['0x01', '0x', '0x']])
true

> caver.utils.isEmptySig(['0x01', '0x', '0x'])
true

> caver.utils.isValidRole([['0x25', '0xf3d0cd43661cabf53425535817c5058c27781f478cb5459874feaa462ed3a29a', '0x6748abe186269ff10b8100a4b7d7fea274b53ea2905acbf498dc8b5ab1bf4fbc']])
false
```

## isKlaytnWalletKey <a href="#isklaytnwalletkey" id="isklaytnwalletkey"></a>

```javascript
caver.utils.isKlaytnWalletKey(key)
```

키가 [KlaytnWalletKey](/content/klaytn/design/accounts.md#klaytn-wallet-key-format) 포맷이면 `true`를 반환하고, 그렇지 않으면 `false`를 반환합니다.

**참고**`caver.utils.isKlaytnWalletKey`는 caver-js [v1.3.2-rc.3](https://www.npmjs.com/package/caver-js/v/1.3.2-rc.3)부터 더 정확한 결과를 제공하기 위해 업데이트되었습니다.

**Parameters**

| Name | Type   | Description                                                    |
| ---- | ------ | -------------------------------------------------------------- |
| key  | String | A key string to check in the format of KlaytnWalletKey or not. |

**Return Value**

| Type    | Description                                                                                                       |
| ------- | ----------------------------------------------------------------------------------------------------------------- |
| Boolean | `true` means the key is `0x{private key}0x{type}0x{address in hex}` or `{private key}0x{type}0x{address in hex}`. |

**Examples**

```javascript
> caver.utils.isKlaytnWalletKey('0x{private key}0x{type}0x{address in hex}')
true

> caver.utils.isKlaytnWalletKey('{private key}0x{type}0x{address in hex}')
true

> caver.utils.isKlaytnWalletKey('0x{private key}')
false
```

## bufferToHex <a href="#buffertohex" id="buffertohex"></a>

```javascript
caver.utils.bufferToHex(buffer)
```

Converts buffer to 0x-prefixed hex string.

**참고** `caver.utils.bufferToHex`는 caver-js [v1.3.2-rc.1](https://www.npmjs.com/package/caver-js/v/1.3.2-rc.1)부터 지원됩니다.

**Parameters**

| Name   | Type   | Description                        |
| ------ | ------ | ---------------------------------- |
| buffer | Buffer | A buffer to convert to hex string. |

**Return Value**

| Type   | Description                 |
| ------ | --------------------------- |
| String | The 0x-prefixed hex string. |

**Examples**

```javascript
> caver.utils.bufferToHex(Buffer.from('5b9ac8', 'hex'))
'0x5b9ac8'

> caver.utils.bufferToHex(Buffer.alloc(0))
'0x'
```