caver.utils
caver-js utility APIs.
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caver-js utility APIs.
Last updated
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caver.utils provides utility functions.
The 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
Example
Parameters
Name
Type
Description
number
string | number
number to convert to a big number.
Return Value
Type
Description
Object
Examples
Parameters
Name
Type
Description
bn
object
Return Value
Type
Description
boolean
Example
Parameters
Name
Type
Description
bignumber
object
Return Value
Type
Description
boolean
true if a given value is a BigNumber.js instance.
Example
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Return Value
Type
Description
boolean
true means the transaction object is for smart contract deploy.
Examples
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
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
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
Returns the result with 0x prefix stripped from input.
Parameters
Name
Type
Description
input
string
string to remove 0x prefix.
Return Value
Type
Description
string
A string stripped of 0x is returned.
Examples
Parameters
Name
Type
Description
input
Buffer | string | number | Array | BN | BigNumber | object
The value to be converted to a Buffer.
Return Value
Type
Description
Buffer
The value converted to Buffer type is returned.
Examples
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
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
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
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.
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
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
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
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
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
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
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
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
Return Value
Type
Description
boolean
true means the sig is empty.
Examples
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
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
Parameters
Name
Type
Description
key
string
Return Value
Type
Description
Array
The parsed KlaytnWalletKey.
Examples
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
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
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
Recovers the public key that was used to sign the given data.
Parameters
Name
Type
Description
message
string
Either message or hashed message.
signature
object | Array
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
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.
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
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
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
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
Decodes a raw signature data composed of 'R(32 byte) + S(32 byte) + V(1byte)'.
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
The library for many convenient JavaScript functions.
See the for details.
Safely converts any given value (including instances) into a instance, for handling big numbers in JavaScript.
The instance.
Checks if a given value is a instance.
A instance.
true if a given value is a instance.
Checks if a given value is a instance.
A instance.
NOTE: To mimic the sha3 behavior of Solidity use .
Checks if a given string is a HEX string. Difference to is that it expects HEX to be prefixed with 0x.
NOTE: This is not useful for big numbers, rather use .
If the number parameter is an instance of , it returns a BN instance, otherwise a string.
An instance of to check contract deploy transaction or not.
Returns the x and y coordinates of the given publicKey. For more information on key cryptography, see .
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 .
NOTE caver.klay.stripHexPrefix is supported from v1.0.1. To use this feature, please install or higher.
This function converts the input to a . 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 BigNumber type is supported since caver-js .
This function converts a number to a . The has the same behavior as this function when the input is a number.
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 is that it expects HEX to be prefixed with 0x.
NOTE This function has been deprecated. Use to determine if a valid hash is 32 bytes long.
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 is that it expects HEX to be prefixed with 0x.
NOTE This function has been deprecated. Use to determine if a valid hash is 32 bytes long.
An instance of or array of to check empty or not.
Returns true if key is in format, otherwise it returns false.
Parses string to an array which includes "private key", "type", "address".
A string.
An instance of .
NOTE caver.utils.recoverPublicKey is supported since caver-js .
An instance of .
NOTE caver.utils.publicKeyToAddress is supported since caver-js .
NOTE caver.utils.decodeSignature is supported since caver-js .