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caver.utils
caver-js utility APIs.
caver.utils provides utility functions.randomHex
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caver.utils.randomHex(size)
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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
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> caver.utils.randomHex(32)
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'0x861b56754dba7769f9740c3ad70b4694aa24d604c1dba3bac7ec45978927b8de'
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> caver.utils.randomHex(4)
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'0x5641d6ce'
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> caver.utils.randomHex(2)
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'0xf058'
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> caver.utils.randomHex(1)
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'0x7c'
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> caver.utils.randomHex(0)
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'0x'
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_
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caver.utils._()
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Example
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> var _ = caver.utils._
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> _.union([1,2],[3])
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[1,2,3]
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> _.each({my: 'object'}, function(value, key){ ... })
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...
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toBN
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caver.utils.toBN(number)
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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
Examples
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> caver.utils.toBN(1234).toString()
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'1234'
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> caver.utils.toBN('1234').add(caver.utils.toBN('1')).toString()
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'1235'
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> caver.utils.toBN('0xea').toString()
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'234'
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isBN
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caver.utils.isBN(bn)
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Parameters
Name
Type
Description
Return Value
Type
Description
boolean
Example
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> var number = new caver.utils.BN(10)
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> caver.utils.isBN(number)
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true
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isBigNumber
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caver.utils.isBigNumber(bignumber)
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Parameters
Name
Type
Description
Return Value
Type
Description
boolean
true if a given value is a BigNumber.js instance.Example
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> var number = new caver.utils.BigNumber(10)
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> caver.utils.isBigNumber(number)
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true
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sha3
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caver.utils.sha3(str)
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caver.utils.keccak256(str) // ALIAS
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Calculates the sha3 of the input.
Parameters
Name
Type
Description
str
string
A string to hash.
Return Value
Type
Description
string
The result hash.
Example
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> caver.utils.sha3('234') // taken as string
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'0xc1912fee45d61c87cc5ea59dae311904cd86b84fee17cc96966216f811ce6a79'
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> caver.utils.sha3(new caver.utils.BN('234')) // utils.sha3 stringify bignumber instance.
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'0xc1912fee45d61c87cc5ea59dae311904cd86b84fee17cc96966216f811ce6a79'
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> caver.utils.sha3(234)
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null // can't calculate the has of a number
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> caver.utils.sha3(0xea) // same as above, just the HEX representation of the number
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null
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> caver.utils.sha3('0xea') // will be converted to a byte array first, and then hashed
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'0x2f20677459120677484f7104c76deb6846a2c071f9b3152c103bb12cd54d1a4a'
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soliditySha3
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caver.utils.soliditySha3(param1 [, param2, ...])
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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.
- `stringReturn Value
Type
Description
string
The result hash.
Example
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> caver.utils.soliditySha3('234564535', '0xfff23243', true, -10)
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// auto detects: uint256, bytes, bool, int256
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'0x3e27a893dc40ef8a7f0841d96639de2f58a132be5ae466d40087a2cfa83b7179'
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> caver.utils.soliditySha3('Hello!%') // auto detects: string
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'0x661136a4267dba9ccdf6bfddb7c00e714de936674c4bdb065a531cf1cb15c7fc'
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> caver.utils.soliditySha3('234') // auto detects: uint256
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'0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2'
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> caver.utils.soliditySha3(0xea) // same as above
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'0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2'
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> caver.utils.soliditySha3(new caver.utils.BN('234')) // same as above
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'0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2'
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> caver.utils.soliditySha3({type: 'uint256', value: '234'})) // same as above
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'0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2'
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> caver.utils.soliditySha3({t: 'uint', v: new caver.utils.BN('234')})) // same as above
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'0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2'
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> caver.utils.soliditySha3('0x407D73d8a49eeb85D32Cf465507dd71d507100c1')
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'0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b'
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> caver.utils.soliditySha3({t: 'bytes', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'})
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'0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b' // same result as above
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> caver.utils.soliditySha3({t: 'address', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'})
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'0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b' // same as above, but will do a checksum check, if its multi case
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> caver.utils.soliditySha3({t: 'bytes32', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'})
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'0x3c69a194aaf415ba5d6afca734660d0a3d45acdc05d54cd1ca89a8988e7625b4' // different result as above
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> caver.utils.soliditySha3({t: 'string', v: 'Hello!%'}, {t: 'int8', v:-23}, {t: 'address', v: '0x85F43D8a49eeB85d32Cf465507DD71d507100C1d'})
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'0xa13b31627c1ed7aaded5aecec71baf02fe123797fffd45e662eac8e06fbe4955'
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isHex
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caver.utils.isHex(hex)
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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
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> caver.utils.isHex('0xc1912')
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true
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> caver.utils.isHex('c1912')
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true
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> caver.utils.isHex('0xZ1912')
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false
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> caver.utils.isHex('Hello')
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false
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isHexStrict
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caver.utils.isHexStrict(hex)
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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
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> caver.utils.isHexStrict('0xc1912')
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true
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> caver.utils.isHexStrict('c1912')
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false
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> caver.utils.isHexStrict('0xZ1912')
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false
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> caver.utils.isHex('Hello')
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false
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isAddress
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caver.utils.isAddress(address)
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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
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> caver.utils.isAddress('0xc1912fee45d61c87cc5ea59dae31190fffff232d')
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true
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> caver.utils.isAddress('c1912fee45d61c87cc5ea59dae31190fffff232d')
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true
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> caver.utils.isAddress('0XC1912FEE45D61C87CC5EA59DAE31190FFFFF232D')
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true // as all is uppercase, no checksum will be checked
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> caver.utils.isAddress('0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d')
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true
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> caver.utils.isAddress('0xC1912fEE45d61C87Cc5EA59DaE31190FFFFf232d')
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false // wrong checksum
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toChecksumAddress
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caver.utils.toChecksumAddress(address)
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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
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> caver.utils.toChecksumAddress('0xc1912fee45d61c87cc5ea59dae31190fffff232d')
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'0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d'
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> caver.utils.toChecksumAddress('0XC1912FEE45D61C87CC5EA59DAE31190FFFFF232D')
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'0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d' // same as above
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checkAddressChecksum
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caver.utils.checkAddressChecksum(address)
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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
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> caver.utils.checkAddressChecksum('0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d')
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true
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toHex
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caver.utils.toHex(mixed)
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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
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> caver.utils.toHex('234')
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'0xea'
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> caver.utils.toHex(234)
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'0xea'
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> caver.utils.toHex(new caver.utils.BN('234'))
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'0xea'
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> caver.utils.toHex(new caver.utils.BigNumber('234'))
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'0xea'
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> caver.utils.toHex('I have 100€')
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'0x49206861766520313030e282ac'
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hexToNumberString
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caver.utils.hexToNumberString(hex)
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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
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> caver.utils.hexToNumberString('0xea')
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"234"
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hexToNumber
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caver.utils.hexToNumber(hex)
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Returns the number representation of a given HEX value.
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
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> caver.utils.hexToNumber('0xea')
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234
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numberToHex
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caver.utils.numberToHex(number)
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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
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> caver.utils.numberToHex('234')
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'0xea'
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hexToUtf8
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caver.utils.hexToUtf8(hex)
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caver.utils.hexToString(hex) // ALIAS
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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
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> caver.utils.hexToUtf8('0x49206861766520313030e282ac')
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'I have 100€'
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hexToAscii
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caver.utils.hexToAscii(hex)
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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
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> caver.utils.hexToAscii('0x4920686176652031303021')
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'I have 100!'
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utf8ToHex
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caver.utils.utf8ToHex(str)
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caver.utils.stringToHex(str) // ALIAS
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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
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> caver.utils.utf8ToHex('I have 100€')
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'0x49206861766520313030e282ac'
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asciiToHex
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caver.utils.asciiToHex(str)
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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
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> caver.utils.asciiToHex('I have 100!')
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'0x4920686176652031303021'
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hexToBytes
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caver.utils.hexToBytes(hex)
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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
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> caver.utils.hexToBytes('0x000000ea')
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[ 0, 0, 0, 234 ]
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bytesToHex
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caver.utils.bytesToHex(byteArray)
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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
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> caver.utils.bytesToHex([ 72, 101, 108, 108, 111, 33, 36 ])
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'0x48656c6c6f2124'
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convertToPeb
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caver.utils.convertToPeb(number [, unit])
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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
Examples
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> caver.utils.convertToPeb('1', 'KLAY')
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'1000000000000000000'
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> caver.utils.convertToPeb(caver.utils.toBN(1), 'KLAY')
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<BN: de0b6b3a7640000>
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convertFromPeb
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caver.utils.convertFromPeb(number [, unit])
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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
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> caver.utils.convertFromPeb('1', 'KLAY')
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'0.000000000000000001'
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unitMap
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caver.utils.unitMap
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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
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> caver.utils.unitMap
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{
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peb: '1',
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kpeb: '1000',
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Mpeb: '1000000',
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Gpeb: '1000000000',
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Ston: '1000000000',
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uKLAY: '1000000000000',
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mKLAY: '1000000000000000',
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KLAY: '1000000000000000000',
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kKLAY: '1000000000000000000000',
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MKLAY: '1000000000000000000000000',
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GKLAY: '1000000000000000000000000000',
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TKLAY: '1000000000000000000000000000000'
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}
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klayUnit
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caver.utils.klayUnit
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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
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> caver.utils.klayUnit
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{
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peb: { unit: 'peb', pebFactor: 0 },
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kpeb: { unit: 'kpeb', pebFactor: 3 },
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Mpeb: { unit: 'Mpeb', pebFactor: 6 },
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Gpeb: { unit: 'Gpeb', pebFactor: 9 },
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ston: { unit: 'ston', pebFactor: 9 },
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uKLAY: { unit: 'uKLAY', pebFactor: 12 },
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mKLAY: { unit: 'mKLAY', pebFactor: 15 },
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KLAY: { unit: 'KLAY', pebFactor: 18 },
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kKLAY: { unit: 'kKLAY', pebFactor: 21 },
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MKLAY: { unit: 'MKLAY', pebFactor: 24 },
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GKLAY: { unit: 'GKLAY', pebFactor: 27 },
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TKLAY: { unit: 'TKLAY', pebFactor: 30 }
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}
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padLeft
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caver.utils.padLeft(string, characterAmount [, sign])
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caver.utils.leftPad(string, characterAmount [, sign]) // ALIAS
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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
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> caver.utils.padLeft('0x3456ff', 20)
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'0x000000000000003456ff'
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> caver.utils.padLeft(0x3456ff, 20)
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'0x000000000000003456ff'
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> caver.utils.padLeft('Hello', 20, 'x')
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'xxxxxxxxxxxxxxxHello'
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padRight
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caver.utils.padRight(str, characterAmount [, sign])
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caver.utils.rightPad(str, characterAmount [, sign]) // ALIAS
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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
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> caver.utils.padRight('0x3456ff', 20)
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'0x3456ff00000000000000'
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> caver.utils.padRight(0x3456ff, 20)
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'0x3456ff00000000000000'
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> caver.utils.padRight('Hello', 20, 'x')
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'Helloxxxxxxxxxxxxxxx'
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trimLeadingZero
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caver.utils.trimLeadingZero(hexString)
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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
1
> caver.utils.trimLeadingZero('0x000011')
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0x11
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makeEven
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caver.utils.makeEven(hexString)
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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
1
> caver.utils.makeEven('0x011')
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0x0011
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toTwosComplement
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caver.utils.toTwosComplement(num)
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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
1
> caver.utils.toTwosComplement('-1')
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'0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff'
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> caver.utils.toTwosComplement(-1)
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'0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff'
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> caver.utils.toTwosComplement('0x1')
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'0x0000000000000000000000000000000000000000000000000000000000000001'
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> caver.utils.toTwosComplement(-15)
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'0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff1'
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> caver.utils.toTwosComplement('-0x1')
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'0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff'
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isContractDeployment
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caver.utils.isContractDeployment(transactionObject)
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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
Return Value
Type
Description
boolean
true means the transaction object is for smart contract deploy.Examples
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> caver.utils.isContractDeployment(caver.transaction.legacyTransaction.create({
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to: '0x9957dfd92e4b70f91131c573293343bc5f21f215',
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value: caver.utils.toPeb(1, 'KLAY'),
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gas: 25000,
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}))
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false
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> caver.utils.isContractDeployment(caver.transaction.legacyTransaction.create({
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input: '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',
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gas: 200000,
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}))
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true
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> caver.utils.isContractDeployment(caver.transaction.smartContractDeploy.create({
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from: