caver.klay.abi

caver-js APIs related to ABI encoding and decoding.

The caver-klay-abi package allows you to de- and encode parameters from an ABI (Application Binary Interface). This will be used for calling functions of a deployed smart-contract.

encodeFunctionSignature

caver.klay.abi.encodeFunctionSignature(functionSignature)

Encodes the function signature to its ABI signature, which are the first 4 bytes of the sha3 hash of the function name including types.

Parameters

Name	Type	Description
functionSignature	String | Object	The function signature or the JSON interface object of the function to encode. If String it has to be in the form function(type,type,...), e.g: myFunction(uint256,uint32[],bytes10,bytes)

Return Value

Type	Description
String	The ABI signature of the function.

Examples

// From a JSON interface object
caver.klay.abi.encodeFunctionSignature({
    name: 'myMethod',
    type: 'function',
    inputs: [{
        type: 'uint256',
        name: 'myNumber'
    },{
        type: 'string',
        name: 'myString'
    }]
})
> 0x24ee0097

// From a function signature
caver.klay.abi.encodeFunctionSignature('myMethod(uint256,string)')
> '0x24ee0097'

encodeEventSignature

caver.klay.abi.encodeEventSignature(eventSignature)

Encodes the event signature to its ABI signature, which is the sha3 hash of the event name including input types.

Parameters

Name	Type	Description
eventSignature	String | Object	The event signature or the JSON interface object of the event to encode. If string it has to be in the form event(type,type,...), e.g: myEvent(uint256,uint32[],bytes10,bytes)

Return Value

Type	Description
String	The ABI signature of the event.

Examples

// From a JSON interface object
caver.klay.abi.encodeEventSignature({
    name: 'myEvent',
    type: 'event',
    inputs: [{
        type: 'uint256',
        name: 'myNumber'
    },{
        type: 'bytes32',
        name: 'myBytes'
    }]
})
> 0xf2eeb729e636a8cb783be044acf6b7b1e2c5863735b60d6daae84c366ee87d97

// From an event signature
caver.klay.abi.encodeEventSignature('myEvent(uint256,bytes32)')
> 0xf2eeb729e636a8cb783be044acf6b7b1e2c5863735b60d6daae84c366ee87d97

encodeParameter

caver.klay.abi.encodeParameter(type, parameter)

Encodes a parameter based on its type to its ABI representation.

Parameters

Name	Type	Description
type	String | Object	The type of the parameter, see the solidity documentation for a list of types.
parameter	Mixed	The actual parameter to encode.

Return Value

Type	Description
String	The ABI encoded parameter.

Examples

caver.klay.abi.encodeParameter('uint256', '2345675643')
> "0x000000000000000000000000000000000000000000000000000000008bd02b7b"

caver.klay.abi.encodeParameter('bytes32', caver.utils.rightPad('0xdf3234', 64))
> "0xdf32340000000000000000000000000000000000000000000000000000000000"

caver.klay.abi.encodeParameter('bytes', '0xdf3234')
> "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000003df32340000000000000000000000000000000000000000000000000000000000"

caver.klay.abi.encodeParameter('bytes32[]', [caver.utils.rightPad('0xdf3234', 64), caver.utils.rightPad('0xfdfd', 64)])
> "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002df32340000000000000000000000000000000000000000000000000000000000fdfd000000000000000000000000000000000000000000000000000000000000"

encodeParameters

caver.klay.abi.encodeParameters(typesArray, parameters)

Encodes function parameters based on its JSON interface object.

Parameters

Name	Type	Description
typesArray	Array|Object	An array with types or a JSON interface of a function. See the solidity documentation for a list of types.
parameters	Array	The parameters to encode.

Return Value

Type	Description
String	The ABI encoded parameters.

Examples

caver.klay.abi.encodeParameters(['uint256','string'], ['2345675643', 'Hello!%'])
> "0x000000000000000000000000000000000000000000000000000000008bd02b7b0000000000000000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000000748656c6c6f212500000000000000000000000000000000000000000000000000"

caver.klay.abi.encodeParameters(['uint8[]','bytes32'], [['34','255'], caver.utils.rightPad('0x324567fff', 64)])
> "0x0000000000000000000000000000000000000000000000000000000000000040324567fff00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000002200000000000000000000000000000000000000000000000000000000000000ff"

encodeFunctionCall

caver.klay.abi.encodeFunctionCall(jsonInterface, parameters)

Encodes a function call using its JSON interface object and given parameters.

Parameters

Name	Type	Description
jsonInterface	Object	The JSON interface object of a function.
parameters	Array	The parameters to encode.

Return Value

Type	Description
String	The ABI encoded function call, which means function signature + parameters.

Examples

caver.klay.abi.encodeFunctionCall({
    name: 'myMethod',
    type: 'function',
    inputs: [{
        type: 'uint256',
        name: 'myNumber'
    },{
        type: 'string',
        name: 'myString'
    }]
}, ['2345675643', 'Hello!%'])
> "0x24ee0097000000000000000000000000000000000000000000000000000000008bd02b7b0000000000000000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000000748656c6c6f212500000000000000000000000000000000000000000000000000"

decodeParameter

caver.klay.abi.decodeParameter(type, hexString)

Decodes an ABI encoded parameter to its JavaScript type.

Parameters

Name	Type	Description
type	String|Object	The type of the parameter, see the solidity documentation for a list of types.
hexString	Array	The ABI byte code to decode.

Return Value

Type	Description
Mixed	The decoded parameter.

Examples

caver.klay.abi.decodeParameter('uint256', '0x0000000000000000000000000000000000000000000000000000000000000010')
> "16"

caver.klay.abi.decodeParameter('string', '0x0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000848656c6c6f212521000000000000000000000000000000000000000000000000')
> "Hello!%!"

decodeParameters

caver.klay.abi.decodeParameters(typesArray, hexString)

Decodes ABI encoded parameters to its JavaScript types.

Parameters

Name	Type	Description
typesArray	Array|Object	An array with types or a JSON interface outputs array. See the solidity documentation for a list of types.
hexString	String	The ABI byte code to decode.

Return Value

Type	Description
Object	The result object containing the decoded parameters.

Examples

caver.klay.abi.decodeParameters(['string', 'uint256'], '0x000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000ea000000000000000000000000000000000000000000000000000000000000000848656c6c6f212521000000000000000000000000000000000000000000000000')
> Result { '0': 'Hello!%!', '1': '234' }

caver.klay.abi.decodeParameters([{
        type: 'string',
        name: 'myString'
    },{
        type: 'uint256',
        name: 'myNumber'
    }], '0x000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000ea000000000000000000000000000000000000000000000000000000000000000848656c6c6f212521000000000000000000000000000000000000000000000000')
> Result {
    '0': 'Hello!%!',
    '1': '234',
    myString: 'Hello!%!',
    myNumber: '234'
}

decodeLog

caver.klay.abi.decodeLog(inputs, hexString, topics)

Decodes ABI encoded log data and indexed topic data.

Parameters

Name	Type	Description
inputs	Array	A JSON interface inputs array. See the solidity documentation for a list of types.
hexString	String	The ABI byte code in the data field of a log.
topics	Array	An array with the index parameter topics of the log, without the topic[0] if its a non-anonymous event, otherwise with topic[0].

Return Value

Type	Description
Object	The result object containing the decoded parameters.

Examples

caver.klay.abi.decodeLog([{
        type: 'string',
        name: 'myString'
    },{
        type: 'uint256',
        name: 'myNumber',
        indexed: true
    },{
        type: 'uint8',
        name: 'mySmallNumber',
        indexed: true
    }],
    '0x0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000748656c6c6f252100000000000000000000000000000000000000000000000000',
    ['0x000000000000000000000000000000000000000000000000000000000000f310', '0x0000000000000000000000000000000000000000000000000000000000000010'])
> Result {
    '0': 'Hello%!',
    '1': '62224',
    '2': '16',
    myString: 'Hello%!',
    myNumber: '62224',
    mySmallNumber: '16'
}

encodeContractDeploy

caver.klay.abi.encodeContractDeploy(jsonInterface, hexString, params)

Encode smart contract bytecode with the arguments of the constructor.

Parameters

Name	Type	Description
jsonInterface	Array	The JSON interface of the contract.
hexString	String	A bytecode of smart contract to be deployed.
params	Mixed	Arguments to pass to the constructor.

Return Value

Type	Description
String	The ABI encoded smart contract deployment with constructor arguments, which means byteCode + parameters.

Examples

// There is no argument for constructor
caver.klay.abi.encodeContractDeploy([
        {"constant": true, "inputs": [], "name": "count", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, 
        { "constant": true, "inputs": [], "name": "getBlockNumber", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, 
        { "constant": false, "inputs": [ { "name": "_count", "type": "uint256" } ], "name": "setCount", "outputs": [], "payable": false, "stateMutability": "nonpayable", "type": "function" }
    ],'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')
> "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"

// There is one argument for constructor(uint256)
caver.klay.abi.encodeContractDeploy([ 
        { "constant": true, "inputs": [], "name": "count", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, 
        { "constant": true, "inputs": [], "name": "getBlockNumber", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, 
        { "constant": false, "inputs": [ { "name": "_count", "type": "uint256" } ], "name": "setCount", "outputs": [], "payable": false, "stateMutability": "nonpayable", "type": "function" }, 
        { "inputs": [ { "name": "_a", "type": "uint256" } ], "payable": false, "stateMutability": "nonpayable", "type": "constructor" } 
    ],'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', 1)
> "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"

// There are two arguments for constructor(uint256, uint256)
caver.klay.abi.encodeContractDeploy([ 
        { "constant": true, "inputs": [], "name": "count", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, 
        { "constant": true, "inputs": [], "name": "getBlockNumber", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, 
        { "constant": false, "inputs": [ { "name": "_count", "type": "uint256" } ], "name": "setCount", "outputs": [], "payable": false, "stateMutability": "nonpayable", "type": "function" }, 
        { "inputs": [ { "name": "_a", "type": "uint256" }, { "name": "_b", "type": "uint256" } ], "payable": false, "stateMutability": "nonpayable", "type": "constructor" } 
    ],'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', 1, 2)
> "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"

// There is one argument for constructor(string)
caver.klay.abi.encodeContractDeploy([ 
        { "constant": true, "inputs": [], "name": "count", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, 
        { "constant": true, "inputs": [], "name": "getBlockNumber", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, 
        { "constant": false, "inputs": [ { "name": "_count", "type": "uint256" } ], "name": "setCount", "outputs": [], "payable": false, "stateMutability": "nonpayable", "type": "function" }, 
        { "inputs": [ { "name": "_a", "type": "string" } ], "payable": false, "stateMutability": "nonpayable", "type": "constructor" } 
    ],'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', 'stringParams')
> "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"