caver.utils

caver.utils provides utility functions.

randomHex

caver.utils.randomHex(size)

The randomHex library to generate cryptographically strong pseudo-random HEX strings from a given byte size.

Parameters

Name	Type	Description
size	Number	The byte size for the HEX string, e.g., 32 will result in a 32-byte HEX string with 64 characters preficed with "0x".

Return Value

Type	Description
String	The generated random HEX string.

Example

> 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"

_ (underscore)

caver.utils._()

The underscore library for many convenience JavaScript functions.

See the underscore API reference for details.

Example

> var _ = caver.utils._;

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

[1,2,3]

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

...

BN

caver.utils.BN(mixed)

The BN.js library for calculating with big numbers in JavaScript. See the BN.js documentation for details.

Parameters

Name	Type	Description
mixed	String | Number	A number, number string or HEX string to convert to a BN object.

Return Value

Type	Description
Object	The BN.js instance.

Example

> 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

caver.utils.isBN(bn)

Checks if a given value is a BN.js instance.

Parameters

Name	Type	Description
bn	Object	A BN.js instance.

Return Value

Type	Description
Boolean	true if a given value is a BN.js instance.

Example

> var number = new BN(10);

> caver.utils.isBN(number);

true

isBigNumber

caver.utils.isBigNumber(bignumber)

Checks if a given value is a BigNumber.js instance.

Parameters

Name	Type	Description
bignumber	Object	A BigNumber.js instance.

Return Value

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

Example

> var number = new BigNumber(10);

> caver.utils.isBigNumber(number);

true

sha3

caver.utils.sha3(string)

caver.utils.keccak256(string) // ALIAS

Calculates the sha3 of the input.

NOTE: To mimic the sha3 behavior of Solidity use caver.utils.soliditySha3.

Parameters

Name	Type	Description
string	String	A string to hash.

Return Value

Type	Description
String	The result hash.

Example

> 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

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	Any type, or an object with {type: 'uint', value: '123456'} or {t: 'bytes', v: '0xfff456'}. Basic types are autodetected as follows: - String non numerical UTF-8 string is interpreted as string. - String|Number|BN|HEX positive number is interpreted as uint256. - String|Number|BN negative number is interpreted as int256. - Boolean as bool. - String HEX string with leading 0x is interpreted as bytes. - HEX HEX number representation is interpreted as uint256.

Return Value

Type	Description
String	The result hash.

Example

> 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

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

> 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

caver.utils.isHexStrict(hex)

Checks if a given string is a HEX string. Difference to caver.utils.isHex is that it expects HEX to be prefixed with 0x.

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

> 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

caver.utils.isAddress(address)

Checks if a given string is a valid Klaytn address. It will also check the checksum, if the address has upper and lowercase letters.

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

> 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

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

> caver.utils.toChecksumAddress('0xc1912fee45d61c87cc5ea59dae31190fffff232d');

"0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d"

> caver.utils.toChecksumAddress('0XC1912FEE45D61C87CC5EA59DAE31190FFFFF232D');

"0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d" // same as above

checkAddressChecksum

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

> caver.utils.checkAddressChecksum('0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d');

true

toHex

caver.utils.toHex(mixed)

Converts any given value to HEX. Number strings will interpreted as numbers. Text strings will be interpreted as UTF-8 strings.

Parameters

Name	Type	Description
mixed	String | Number | BN | BigNumber	The input to convert to HEX.

Return Value

Type	Description
String	The resulting HEX string.

Examples

> 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

caver.utils.toBN(number)

Safely converts any given value (including BigNumber.js instances) into a BN.js instance, for handling big numbers in JavaScript.

NOTE: For just the BN.js class, use caver.utils.BN.

Parameters

Name	Type	Description
number	String | Number | HEX	Number to convert to a big number.

Return Value

Type	Description
Object	The BN.js instance.

Examples

> caver.utils.toBN(1234).toString();

"1234"

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

"1235"

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

"234"

hexToNumberString

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

> caver.utils.hexToNumberString('0xea');

"234"

hexToNumber

caver.utils.hexToNumber(hex)

Returns the number representation of a given HEX value.

NOTE: This is not useful for big numbers, rather use caver.utils.toBN.

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

> caver.utils.hexToNumber('0xea');

234

numberToHex

caver.utils.numberToHex(number)

Returns the HEX representation of a given number value.

Parameters

Name	Type	Description
number	String | Number | BN | BigNumber	A number as string or number.

Return Value

Type	Description
String	The HEX value of the given number.

Examples

> caver.utils.numberToHex('234');

'0xea'

hexToUtf8

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

> caver.utils.hexToUtf8('0x49206861766520313030e282ac');

"I have 100€"

hexToAscii

caver.utils.hexToAscii(hex)

Returns the ASCII string representation of a given HEX value.

Parameters

Name	Type	Description
hex	String	A HEX string to convert to a ASCII string.

Return Value

Type	Description
String	The ASCII string.

Examples

> caver.utils.hexToAscii('0x4920686176652031303021');

"I have 100!"

utf8ToHex

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

> caver.utils.utf8ToHex('I have 100€');

"0x49206861766520313030e282ac"

asciiToHex

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

> caver.utils.asciiToHex('I have 100!');

"0x4920686176652031303021"

hexToBytes

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

> caver.utils.hexToBytes('0x000000ea');

[ 0, 0, 0, 234 ]

bytesToHex

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

> caver.utils.bytesToHex([ 72, 101, 108, 108, 111, 33, 36 ]);

"0x48656c6c6f2125"

toPeb

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

Converts any KLAY value into peb.

NOTE: "peb" is the smallest KLAY unit, and you should always make calculations in peb and convert only for display reasons.

Parameters

Name	Type	Description
number	String | Number | BN	The value.
unit	String	(optional, defaults to "KLAY") KLAY to convert from. Possible units are:- peb: '1' - kpeb: '1000' - Mpeb: '1000000' - Gpeb: '1000000000' - Ston: '1000000000' - uKLAY: '1000000000000' - mKLAY: '1000000000000000' - KLAY: '1000000000000000000' - kKLAY: '1000000000000000000000' - MKLAY: '1000000000000000000000000' - GKLAY: '1000000000000000000000000000'

Return Value

Type	Description
String | BN	If a number or a string is given, it returns a number string, otherwise a BN.js instance.

Examples

> caver.utils.toPeb('1', 'KLAY');

"1000000000000000000"

fromPeb

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

NOTE: "peb" is the smallest KLAY unit, and you should always make calculations in KLAY and convert only for display reasons.

Parameters

Name	Type	Description
number	String | Number | BN	The value in peb.
unit	String	(optional, defaults to "KLAY") KLAY to convert to. Possible units are:- peb: '1' - kpeb: '1000' - Mpeb: '1000000' - Gpeb: '1000000000' - Ston: '1000000000' - uKLAY: '1000000000000' - mKLAY: '1000000000000000' - KLAY: '1000000000000000000' - kKLAY: '1000000000000000000000' - MKLAY: '1000000000000000000000000' - GKLAY: '1000000000000000000000000000'

Return Value

Type	Description
String | BN	If a number or a string is given, it returns a number string, otherwise a BN.js instance.

Examples

> caver.utils.fromPeb('1', 'KLAY');

"0.000000000000000001"

unitMap

caver.utils.unitMap

Shows all possible KLAY values and their amount in peb.

Return Value

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

Examples

> 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

caver.utils.padLeft(string, characterAmount [, sign])

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

Adds a padding on the left of a string. 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	(optional) The character sign to use, defaults to "0".

Return Value

Type	Description
String	The padded string.

Examples

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

"0x000000000000003456ff"

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

"0x000000000000003456ff"

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

"xxxxxxxxxxxxxxxHello"

padRight

caver.utils.padRight(string, characterAmount [, sign])

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

Adds a padding on the right of a string, Useful for adding paddings to HEX strings.

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

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

"0x3456ff00000000000000"

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

"0x3456ff00000000000000"

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

"Helloxxxxxxxxxxxxxxx"

toTwosComplement

caver.utils.toTwosComplement(number)

Converts a negative number into a two's complement.

Parameters

Name	Type	Description
number	Number | String | BigNumber	The number to convert.

Return Value

Type	Description
String	The converted hex string.

Examples

> 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

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.

NOTE caver.klay.isContractDeployment is supported from v1.0.1-rc.8. To use this feature, please install v1.0.1-rc.8 or higher.

Parameters

Name	Type	Description
transactionObject	Object	Transaction object that you want to determine if the transaction is for smart contract deploy.

Return Value

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

Examples

> 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: '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',

gas: '0x3b9ac9ff',

})

true

> caver.utils.isContractDeployment({

type: 'ACCOUNT_UPDATE',

from: '0x88e245dec96830f012f8fc1806bc623b3774560d',

publicKey: '0x4ef27ba4b7d1ae09b166744c5b7ee4a7a0cc5c76b2e5d74523a0a4fb56db319162ff3255302045cd047a27141916d55615a7c1ead06e211e62119e7bc2a40def',

nonce: '0x0',

gas: '0x3b9ac9ff',

chainId: '0x7e3',

gasPrice: '0x5d21dba00',

})

false

xyPointFromPublicKey

caver.utils.xyPointFromPublicKey(publicKey)

Returns the x and y coordinates of the given publicKey. For more information on key cryptography, see Elliptic-curve cryptography.

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

> caver.utils.xyPointFromPublicKey('0xa5862ded55cd9c7e9ff246dbc264ca5d5c605308f59b74e581b4f089d4c8c88cb9f00df6a56493f6029af215d266c907660ea0f7a4111ea025ea9d9be418fa55')

[

'0xa5862ded55cd9c7e9ff246dbc264ca5d5c605308f59b74e581b4f089d4c8c88c',

'0xb9f00df6a56493f6029af215d266c907660ea0f7a4111ea025ea9d9be418fa55'

]

isHexPrefixed

caver.utils.isHexPrefixed(input)

Returns true if input is a 0x-prefixed hex string, otherwise it returns false.

NOTE caver.klay.isHexPrefixed is supported from v1.0.1. To use this feature, please install v1.0.1 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

> caver.utils.isHexPrefixed('0xa5b0cd8c87e77879d64cc064ee239ed6f71cacf9')

true

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

true

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

false

> caver.utils.isHexPrefixed('1')

false

addHexPrefix

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.

NOTE caver.klay.addHexPrefix is supported from v1.0.1. To use this feature, please install v1.0.1 or higher.

Parameters

Name	Type	Description
input	String	String value to be prefixed with 0x.

Return Value

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

Examples

> caver.utils.addHexPrefix('a5b0cd8c87e77879d64cc064ee239ed6f71cacf9')

'0xa5b0cd8c87e77879d64cc064ee239ed6f71cacf9'

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

'0xa5b0cd8c87e77879d64cc064ee239ed6f71cacf9'

stripHexPrefix

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 or higher.

Parameters

Name	Type	Description
input	String	String to remove 0x prefix.

Return Value

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

Examples

> caver.utils.stripHexPrefix('a5b0cd8c87e77879d64cc064ee239ed6f71cacf9')

'a5b0cd8c87e77879d64cc064ee239ed6f71cacf9'

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

'a5b0cd8c87e77879d64cc064ee239ed6f71cacf9'

toBuffer

caver.utils.toBuffer(input)

This function converts the input to a Buffer. To convert an Object into a Buffer using toBuffer, the Object must implement toArray function. For String type input, this function only works with a 0x-prefixed hex string.

NOTE caver.klay.toBuffer is supported from v1.1.0. To use this feature, please install v1.1.0 or higher.

Parameters

Name	Type	Description
input	Buffer | String | Number | Array | BN | Object	The value to be converted to a Buffer.

Return Value

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

Examples

// 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

caver.utils.numberToBuffer(input)

This function converts a number to a Buffer. The caver.utils.toBuffer has the same behavior as this function when the input is a number.

NOTE caver.klay.numberToBuffer is supported from v1.1.0. To use this feature, please install v1.1.0 or higher.

Parameters

Name	Type	Description
input	String | Number | BN	A number to be converted to a Buffer.

Return Value

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

Examples

> 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

caver.utils.isTxHash(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. NOTE caver.klay.isTxHash is supported from v1.2.0-rc.1. To use this feature, please install v1.2.0-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 format of transaction hash.

Examples

// with '0x' hex prefix

> caver.utils.isTxHash('0xe9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')

true

// without '0x' hex prefix

> caver.utils.isTxHash('e9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')

true

> caver.utils.isTxHash('0x1')

false

isTxHashStrict

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. Difference to caver.utils.isTxHash is that it expects HEX to be prefixed with 0x. NOTE caver.klay.isTxHashStrict is supported from v1.2.0-rc.1. To use this feature, please install v1.2.0-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

// with '0x' hex prefix

> caver.utils.isTxHashStrict('0xe9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')

true

// without '0x' hex prefix

> caver.utils.isTxHashStrict('e9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')

false

> caver.utils.isTxHashStrict('0x1')

false

isValidPrivateKey

caver.utils.isValidPrivateKey(privateKey)

Returns true if privateKey is valid, otherwise it returns false.

Parameters

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

Return Value

Type	Description
Boolean	true means the privateKey is valid.

Examples

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

true

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

true

> caver.utils.isValidPrivateKey('a5b0cd8c87e77879d64cc064ee239ed6f71cacf9')

false

isValidPublicKey

caver.utils.isValidPublicKey(publicKey)

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

NOTE caver.utils.isValidPublicKey is supported since caver-js v1.2.0.

Parameters

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

Return Value

Type	Description
Boolean	true means the publicKey is valid.

Examples

// 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

caver.utils.isValidRole(role)

Returns true if role is valid, otherwise it returns false. Roles that are currently defined for AccountKeyRoleBased are transactionKey, updateKey, and feePayerKey.

NOTE caver.utils.isValidRole is supported since caver-js v1.2.0.

Parameters

Name	Type	Description
role	String	A role string to validate.

Return Value

Type	Description
Boolean	true means the role is valid.

Examples

> caver.utils.isValidRole('transactionKey')

true

> caver.utils.isValidRole('updateKey')

true

> caver.utils.isValidRole('feePayerKey')

true

> caver.utils.isValidRole('role')

false

isEmptySig

caver.utils.isEmptySig(sig)

Returns true if sig is in the format of empty signature ([['0x01', '0x', '0x']] or ['0x01', '0x', '0x']), otherwise it returns false.

When RLP-encoding a transaction in caver-js, if signatures or feePayerSignatures is empty, the value representing an empty signature, [['0x01', '0x', '0x']], is returned for the property. This function is used to check whether the given signature is [['0x01', '0x', '0x']] (or ['0x01', '0x', '0x'] in the 'LEGACY' transaction).

NOTE caver.utils.isEmptySig is supported since caver-js v1.2.0.

Parameters

Name	Type	Description
sig	Array	An array of signatures to check empty or not.

Return Value

Type	Description
Boolean	true means the sig is [['0x01', '0x', '0x']] or ['0x01', '0x', '0x'].

Examples

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

true

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

true

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

false

isKlaytnWalletKey

caver.utils.isKlaytnWalletKey(key)

Returns true if key is in KlaytnWalletKey format, otherwise it returns false.

NOTE caver.utils.isKlaytnWalletKey has been updated with the additional logic for a more accurate result since caver-js v1.3.2-rc.3.

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

> 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

caver.utils.bufferToHex(buffer)

Converts buffer to 0x-prefixed hex string.

NOTE caver.utils.bufferToHex is supported since caver-js v1.3.2-rc.1.

Parameters

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

Return Value

Type	Description
String	The 0x-prefixed hex string.

Examples

> caver.utils.bufferToHex(Buffer.from('5b9ac8', 'hex'))

'0x5b9ac8'

> caver.utils.bufferToHex(Buffer.alloc(0))

'0x'