caver.utils

caver-js utility APIs.

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 prefixed with "0x".

Return Value

Type	Description
string	The generated random HEX string.

Example

> caver.utils.randomHex(32)
'0x861b56754dba7769f9740c3ad70b4694aa24d604c1dba3bac7ec45978927b8de'

> caver.utils.randomHex(4)
'0x5641d6ce'

> caver.utils.randomHex(2)
'0xf058'

> caver.utils.randomHex(1)
'0x7c'

> caver.utils.randomHex(0)
'0x'

_

caver.utils._()

The underscore library for many convenient 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){ ... })
...

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.

Parameters

Name	Type	Description
number	string | number	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'

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 caver.utils.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 caver.utils.BigNumber(10)
> caver.utils.isBigNumber(number)
true

sha3

caver.utils.sha3(str)
caver.utils.keccak256(str) // ALIAS

Calculates the sha3 of the input.

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

Parameters

Name	Type	Description
str	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 caver.utils.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	HEXpositive number is interpreted asuint256.<br> -string	number	BNnegative number is interpreted asint256.<br> -booleanasbool.<br> -stringHEX string with leading0xis interpreted asbytes.<br> -HEXHEX number representation is interpreted asuint256`.

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 caver.utils.BN('234')) // same as above
'0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2'

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

> caver.utils.soliditySha3({t: 'uint', v: new caver.utils.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	The given HEX string.

Return Value

Type	Description
boolean	true if a given parameter is a HEX string.

Example

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

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

> 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	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('c1912')
false

> 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. The numeric strings will be 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 caver.utils.BN('234'))
'0xea'

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

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

hexToNumberString

caver.utils.hexToNumberString(hex)

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

Parameters

Name	Type	Description
hexstring	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	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 an ASCII string.

Return Value

Type	Description
string	The ASCII string.

Examples

> caver.utils.hexToAscii('0x4920686176652031303021')
'I have 100!'

utf8ToHex

caver.utils.utf8ToHex(str)
caver.utils.stringToHex(str) // ALIAS

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

Parameters

Name	Type	Description
str	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(str)

Returns the HEX representation of a given ASCII string.

Parameters

Name	Type	Description
str	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	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 ])
'0x48656c6c6f2124'

convertToPeb

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

Converts any KLAY value into peb.

NOTE: "peb" is the smallest KLAY unit, and you should always use "peb" as the unit of KLAY. Convert to "KLAY" only for display reasons.

Parameters

Name	Type	Description
number	string | number | BN	The value.
unit	string	(optional, defaults to "KLAY") The unit of KLAY to convert from. number will be multiplied by one of the following multipliers for the unit provided: - 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 the number parameter is an instance of BN, it returns a BN instance, otherwise a string.

Examples

> caver.utils.convertToPeb('1', 'KLAY')
'1000000000000000000'

> caver.utils.convertToPeb(caver.utils.toBN(1), 'KLAY')
<BN: de0b6b3a7640000>

convertFromPeb

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

NOTE: "peb" is the smallest KLAY unit, and you should always use "peb" as the unit of KLAY. Convert to "KLAY" only for display reasons.

Parameters

Name	Type	Description
number	string | number | BN | BigNumber	The value in peb.
unit	string	(optional, defaults to "KLAY") The unit of KLAY to convert your "peb" into. number will be divided by one of the following denominators for the unit provided: - 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	The string number.

Examples

> caver.utils.convertFromPeb('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' - TKLAY: '1000000000000000000000000000000'

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',
  TKLAY: '1000000000000000000000000000000'
}

klayUnit

caver.utils.klayUnit

Shows all KLAY units.

Return Value

Type	Description
Object	An object in which the units of KLAY used in Klaytn are defined. Each unit has its name and pebFactor. pebFactor is used when converting KLAY currently translated in each unit to 'peb'.

Examples

> caver.utils.klayUnit
{
    peb: { unit: 'peb', pebFactor: 0 },
    kpeb: { unit: 'kpeb', pebFactor: 3 },
    Mpeb: { unit: 'Mpeb', pebFactor: 6 },
    Gpeb: { unit: 'Gpeb', pebFactor: 9 },
    ston: { unit: 'ston', pebFactor: 9 },
    uKLAY: { unit: 'uKLAY', pebFactor: 12 },
    mKLAY: { unit: 'mKLAY', pebFactor: 15 },
    KLAY: { unit: 'KLAY', pebFactor: 18 },
    kKLAY: { unit: 'kKLAY', pebFactor: 21 },
    MKLAY: { unit: 'MKLAY', pebFactor: 24 },
    GKLAY: { unit: 'GKLAY', pebFactor: 27 },
    TKLAY: { unit: 'TKLAY', pebFactor: 30 }
}

padLeft

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

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

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

Parameters

Name	Type	Description
str	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'

trimLeadingZero

caver.utils.trimLeadingZero(hexString)

Removes leading zero from 0x-prefixed hex string.

Parameters

Name	Type	Description
hexString	string	A hex string to trim.

Return Value

Type	Description
string	A hex string without leading zero.

Examples

> caver.utils.trimLeadingZero('0x000011')
0x11

makeEven

caver.utils.makeEven(hexString)

Returns a string to an even length.

Parameters

Name	Type	Description
hexString	string	A hex string to make even.

Return Value

Type	Description
string	A string with even length.

Examples

> caver.utils.makeEven('0x011')
0x0011

toTwosComplement

caver.utils.toTwosComplement(num)

Converts a negative number into a two's complement.

Parameters

Name	Type	Description
num	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.

Parameters

Name	Type	Description
transactionObject	object	An instance of Transaction to check contract deploy transaction or not.

Return Value

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

Examples

> caver.utils.isContractDeployment(caver.transaction.legacyTransaction.create({
    to: '0x9957dfd92e4b70f91131c573293343bc5f21f215',
    value: caver.utils.toPeb(1, 'KLAY'),
    gas: 25000,
}))
false

> caver.utils.isContractDeployment(caver.transaction.legacyTransaction.create({
    input: '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',
    gas: 200000,
}))
true

> caver.utils.isContractDeployment(caver.transaction.smartContractDeploy.create({
    from: '0x88e245dec96830f012f8fc1806bc623b3774560d',
    input: '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',
    gas: 100000,
}))
true

> caver.utils.isContractDeployment(caver.transaction.feeDelegatedSmartContractDeploy.create({
    from: '0x88e245dec96830f012f8fc1806bc623b3774560d',
    input: '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',
    gas: 100000,
}))
true

> caver.utils.isContractDeployment(caver.transaction.feeDelegatedSmartContractDeployWithRatio.create({
    from: '0x88e245dec96830f012f8fc1806bc623b3774560d',
    input: '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',
    gas: 100000,
    feeRatio: 30,
}))
true

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. To validate public key, please use isValidPublicKey.

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 the input is a 0x-prefixed hex string, otherwise it returns false.

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.

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.

Parameters

Name	Type	Description
input	Buffer | string | number | Array | BN | BigNumber | object	The value to be converted to a Buffer.

NOTE BigNumber type is supported since caver-js v1.6.4.

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.

Parameters

Name	Type	Description
input	string | number | BN | BigNumber	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>

isValidHash

caver.utils.isValidHash(input)

Returns true if the input is in 32-bytes hash format, otherwise it returns false.

Parameters

Name	Type	Description
input	string	The value to be examined that if it is in 32-bytes hash format or not.

Return Value

Type	Description
boolean	true means the input is in the format of 32-bytes hash.

Examples

// with '0x' hex prefix
> caver.utils.isValidHash('0xe9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')
true

// without '0x' hex prefix
> caver.utils.isValidHash('e9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')
true

> caver.utils.isValidHash('0x1')
false

isValidHashStrict

caver.utils.isValidHashStrict(input)

Returns true if the input is in 0x-prefixed 32-bytes hash format, otherwise it returns false. This function only looks at the input and determines if it is in the format of 0x-prefixed 32-bytes hash. Difference to caver.utils.isValidHash is that it expects HEX to be prefixed with 0x.

Parameters

Name	Type	Description
input	string	The value to be examined that if it is in the format of 0x-prefixed 32-bytes hash or not.

Return Value

Type	Description
boolean	true means the input is in the format of 0x-prefixed 32-bytes hash.

Examples

// with '0x' hex prefix
> caver.utils.isValidHashStrict('0xe9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')
true

// without '0x' hex prefix
> caver.utils.isValidHashStrict('e9a11d9ef95fb437f75d07ce768d43e74f158dd54b106e7d3746ce29d545b550')
false

> caver.utils.isValidHashStrict('0x1')
false

isTxHash

caver.utils.isTxHash(input)

Returns true if the 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 This function has been deprecated. Use isValidHash to determine if a valid hash is 32 bytes long.

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.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 the 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 This function has been deprecated. Use isValidHashStrict to determine if a valid hash is 32 bytes long.

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.

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 a role is valid, otherwise it returns false. You can check roles supported by caver-js through caver.wallet.keyring.role.

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('roleTransactionKey')
true

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

isValidBlockNumberCandidate

caver.utils.isValidBlockNumberCandidate(input)

Validates the block number (or block tag string).

The block number should be one of the types below:

• predefined block number ex:) 'latest', 'earliest', 'pending', 'genesis'

• hex

• finite number

Parameters

Name	Type	Description
blockNumber	string | number	The block number to validate. This can be block number in number type or block tag(latest, pending, earliest, genesis) string.

Return Value

Type	Description
boolean	true means blockNumber is valid.

Examples

> caver.utils.isValidBlockNumberCandidate('latest')
true

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

> caver.utils.isValidBlockNumberCandidate(1)
true

isPredefinedBlockNumber

caver.utils.isPredefinedBlockNumber(input)

Returns true if the parameter is predefined block tag.

Parameters

Name	Type	Description
predefinedBlock	string	The predefined block.

Return Value

Type	Description
boolean	true means predefinedBlock is valid predefined block tag.

Examples

> caver.utils.isPredefinedBlockNumber('latest')
true

> caver.utils.isPredefinedBlockNumber('0x1')
false

isEmptySig

caver.utils.isEmptySig(sig)

Returns true if sig is in the format of empty signature (SignatureData { _v: '0x01', _r: '0x', _s: '0x' } or [SignatureData { _v: '0x01', _r: '0x', _s: '0x' }]), otherwise it returns false.

In caver-js, if signatures or feePayerSignatures is empty, the value representing an empty signature, [SignatureData { _v: '0x01', _r: '0x', _s: '0x' }], is returned for the property. This function is used to check whether the given signature is [SignatureData { _v: '0x01', _r: '0x', _s: '0x' }] (or SignatureData { _v: '0x01', _r: '0x', _s: '0x' } in the 'LEGACY' transaction).

Parameters

Name	Type	Description
sig	object | Array	An instance of SignatureData or array of SignatureData to check empty or not.

Return Value

Type	Description
boolean	true means the sig is empty.

Examples

> caver.utils.isEmptySig(caver.wallet.keyring.signatureData.emtpySig)
true

> caver.utils.isEmptySig([caver.wallet.keyring.signatureData.emtpySig])
true

isKlaytnWalletKey

caver.utils.isKlaytnWalletKey(key)

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

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.

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'

parseKlaytnWalletKey

caver.utils.parseKlaytnWalletKey(key)

Parses KlaytnWalletKey string to an array which includes "private key", "type", "address".

Parameters

Name	Type	Description
key	string	A KlaytnWalletKey string.

Return Value

Type	Description
Array	The parsed KlaytnWalletKey.

Examples

> caver.utils.parseKlaytnWalletKey('0x{private key}0x{type}0x{address in hex}')
[
    '0x{private key}',
    '0x00',
    '0x885ebdb17c221ef695936b18a0263d6399e14d60'
]

hashMessage

caver.utils.hashMessage(message)

Hashes message with Klaytn specific prefix: keccak256("\x19Klaytn Signed Message:\n" + len(message) + message))

Parameters

Name	Type	Description
message	string	A message to hash. If it is a HEX string, it will be UTF-8 decoded first.

Return Value

Type	Description
string	The hashed message with Klaytn specific prefix.

Examples

> caver.utils.hashMessage('Hello')
'0x640bfab59b6e27468abd367888f4ab1a1c77aa2b45e76a1d3adcbd039c305917'

recover

caver.utils.recover(message, signature [, isHashed])

Recovers the Klaytn address that was used to sign the given data.

Parameters

Name	Type	Description
message	string	Either message or hashed message.
signature	object | Array	An instance of SignatureData.
isHashed	boolean	(optional, default: false) If the last parameter is true, the given message will NOT automatically be prefixed with "\x19Klaytn Signed Message:\n" + message.length + message, and will be assumed to be already prefixed.

Return Value

Type	Description
string	The Klaytn address used to sign this data.

Examples

> caver.utils.recover('message', new caver.wallet.keyring.signatureData(['0x1b', '0x50a80...', '0x021de...']))
'0xe8b3a6ef12f9506e1df9fd445f9bb4488a482122'

> caver.utils.recover('message', ['0x1b', '0x50a80...', '0x021de...'])
'0xe8b3a6ef12f9506e1df9fd445f9bb4488a482122'

> caver.utils.recover('message', { v: '0x1b', r: '0x50a80...', s: '0x021de...' })
'0xe8b3a6ef12f9506e1df9fd445f9bb4488a482122'

> caver.utils.recover('0xe960248437f2134a77a9aa0ebcbb6523aec095f23b02e25f16fd95e99b099daa', sig, true)
'0xe8b3a6ef12f9506e1df9fd445f9bb4488a482122'

recoverPublicKey

caver.utils.recoverPublicKey(message, signature [, isHashed])

Recovers the public key that was used to sign the given data.

NOTE caver.utils.recoverPublicKey is supported since caver-js v1.6.3.

Parameters

Name	Type	Description
message	string	Either message or hashed message.
signature	object | Array	An instance of SignatureData.
isHashed	boolean	(optional, default: false) Whether the message passed as a parameter is hashed with the prefix "\x19Klaytn Signed Message:\n" + message.length + message.

Return Value

Type	Description
string	The public key used to sign this data.

Examples

> caver.utils.recoverPublicKey('Some Message', new caver.wallet.keyring.signatureData([
    '0x1b',
    '0x8213e560e7bbe1f2e28fd69cbbb41c9108b84c98cd7c2c88d3c8e3549fd6ab10',
    '0x3ca40c9e20c1525348d734a6724db152b9244bff6e0ff0c2b811d61d8f874f00',
]))
'0xb5df4d5e6b4ee7a136460b911a69030fdd42c18ed067bcc2e25eda1b851314fad994c5fe946aad01ca2e348d4ff3094960661a8bc095f358538af54aeea48ff3'

> caver.utils.recoverPublicKey('Some Message', [
    '0x1b',
    '0x8213e560e7bbe1f2e28fd69cbbb41c9108b84c98cd7c2c88d3c8e3549fd6ab10',
    '0x3ca40c9e20c1525348d734a6724db152b9244bff6e0ff0c2b811d61d8f874f00',
])
'0xb5df4d5e6b4ee7a136460b911a69030fdd42c18ed067bcc2e25eda1b851314fad994c5fe946aad01ca2e348d4ff3094960661a8bc095f358538af54aeea48ff3'

> caver.utils.recoverPublicKey('0x8ed2036502ed7f485b81feaec1c581d236a8b711e55a24077724879c8a263c2a', {
    v: '0x1b',
    r: '0x3acab5ba6f884eccfb9642018aa6debab1310d99b7a84ae9acb8f52f567cf16a',
    s: '0x3501ae03809bf93222c4683642fa8fdc36385709c70ed8e7b883b34d66a5b8a4',
}, true)
'0xdd352dbe1c49aa9addaa3ca762de476a1b4deca3ac15fbb7fac153737b3ddb1e3249e1c2d86d5cbeaf6d30d366a211532683b59cb5f402bf3fe14989a378d45d'

publicKeyToAddress

caver.utils.publicKeyToAddress('0x{public key}')

Returns an address derived from a public key. This function simply converts the public key string into an address form by hashing it. It has nothing to do with an actual account on Klaytn.

NOTE caver.utils.publicKeyToAddress is supported since caver-js v1.6.3.

Parameters

Name	Type	Description
publicKey	string	The public key string to get the address.

Return Value

Type	Description
string	The address string derived from a public key.

Examples

> caver.utils.publicKeyToAddress('0xb5df4d5e6b4ee7a136460b911a69030fdd42c18ed067bcc2e25eda1b851314fad994c5fe946aad01ca2e348d4ff3094960661a8bc095f358538af54aeea48ff3')
'0xA84A1CE657e9d5b383cECE6f4bA365e23Fa234Dd'

compressPublicKey

caver.utils.compressPublicKey(uncompressedPublicKey)

Compresses the uncompressed public key.

Parameters

Name	Type	Description
uncompressedPublicKey	string	An uncompressed public key.

Return Value

Type	Description
string	A compressed public key.

Examples

> caver.utils.compressPublicKey('0x62cef87819b82f62e9c0a38c1fa7dfa089084959df86aca19ff2f6c903db2248b45dc23220ee6bcd8753bb9df8ce7d58e56eabebb14479f3a0ca5ccd4bdea632')
'0x0262cef87819b82f62e9c0a38c1fa7dfa089084959df86aca19ff2f6c903db2248'

decompressPublicKey

caver.utils.decompressPublicKey(compressedPublicKey)

Decompresses the compressed public key.

Parameters

Name	Type	Description
compressedPublicKey	string	A compressed public key.

Return Value

Type	Description
string	An uncompressed public key.

Examples

> caver.utils.decompressPublicKey('0x0262cef87819b82f62e9c0a38c1fa7dfa089084959df86aca19ff2f6c903db2248')
'0x62cef87819b82f62e9c0a38c1fa7dfa089084959df86aca19ff2f6c903db2248b45dc23220ee6bcd8753bb9df8ce7d58e56eabebb14479f3a0ca5ccd4bdea632'

isCompressedPublicKey

caver.utils.isCompressedPublicKey(publicKey)

Returns true if public key is compressed, otherwise false.

Parameters

Name	Type	Description
publicKey	string	A public key.

Return Value

Type	Description
boolean	true means compressed.

Examples

> caver.utils.isCompressedPublicKey('0x0262cef87819b82f62e9c0a38c1fa7dfa089084959df86aca19ff2f6c903db2248')
true

decodeSignature

caver.utils.decodeSignature('0x{signature}')

Decodes a raw signature data composed of 'R(32 byte) + S(32 byte) + V(1byte)'.

NOTE caver.utils.decodeSignature is supported since caver-js v1.6.3.

Parameters

Name	Type	Description
signature	string	The signature string to decode. It is composed of R(32bytes) + S(32bytes) + V(1byte).

Return Value

Type	Description
object	A SignatureData instance that includes v, r and s.

Examples

> caver.utils.decodeSignature('0xc69018da9396c4b87947e0784625af7475caf46e2af9cf57a44673ff0f625258642d8993751ae67271bcc131aa065adccf9f16fc4953f9c48f4a80d675c09ae81b')
SignatureData {
  _v: '0x1b',
  _r: '0xc69018da9396c4b87947e0784625af7475caf46e2af9cf57a44673ff0f625258',
  _s: '0x642d8993751ae67271bcc131aa065adccf9f16fc4953f9c48f4a80d675c09ae8'
}