caver.contract

The caver.contract object makes it easy to interact with smart contracts on the Klaytn blockchain platform. When you create a new contract object, you have to provide the JSON interface for that smart contract and caver-js will automatically convert all calls with the contract object in javascript into low-level ABI calls over RPC for you.

This allows you to interact with smart contracts as if they were JavaScript objects.

caver.contract.create

caver.contract.create(jsonInterface [, address] [, options])

Creates a new contract instance with all its methods and events defined in its JSON interface object. This function works the same as new caver.contract.

NOTE caver.contract.create is supported since caver-js v1.6.1.

Parameters

See the new caver.contract.

Return Value

See the new caver.contract.

Example

const contract = caver.contract.create([
    {
        constant: true,
        inputs: [{ name: 'interfaceId', type: 'bytes4' }],
        name: 'supportsInterface',
        outputs: [{ name: '', type: 'bool' }],
        payable: false,
        stateMutability: 'view',
        type: 'function',
    },
    ...
  ], '0x{address in hex}')

caver.contract

new caver.contract(jsonInterface [, address] [, options])

Creates a new contract instance with all its methods and events defined in its JSON interface object.

Parameters

Name

Type

Description

jsonInterface

object

The JSON interface for the contract to instantiate

address

string

(optional) The address of the smart contract to call. Can be added later using myContract.options.address = '0x1234..'

options

object

(optional) The options of the contract. See the table below for the details.

The options object contains the following:

Name

Type

Description

from

string

(optional) The address from which transactions should be made.

gasPrice

string

(optional) The gas price in peb to use for transactions.

gas

number

(optional) The maximum gas provided for a transaction (gas limit).

data

string

(optional) The byte code of the contract. Used when the contract gets deployed.

feeDelegation

boolean

(optional) Whether to use fee delegation transaction.

feePayer

string

(optional) The address of the fee payer paying the transaction fee. When feeDelegation is true, the value is set to the feePayer field in the transaction.

feeRatio

string

(optional) The ratio of the transaction fee the fee payer will be burdened with. If feeDelegation is true and feeRatio is set to a valid value, a partial fee delegation transaction is used. The valid range of this is between 1 and 99. The ratio of 0, or 100 and above are not allowed.

Return Value

Type

Description

object

The contract instance with all its methods and events.

Example

const myContract = new caver.contract([...], '0x{address in hex}', { gasPrice: '25000000000' })

myContract.options

myContract.options

The options object for the contract instance. from, gas, gasPrice, feePayer and feeRatio are used as fallback values when sending transactions.

Properties

Name

Type

Description

address

string

The address where the contract is deployed.

jsonInterface

Array

The JSON interface of the contract.

from

string

The default address from which the contract deployment/execution transaction is sent. If the from address is not defined when creating the transaction, this myContract.options.from is always used to create the transaction.

gasPrice

string

The gas price in peb to use for transactions.

gas

number

The maximum gas provided for a transaction (gas limit).

data

string

The byte code of the contract. Used when the contract gets deployed.

feeDelegation

boolean

(optional) Whether to use fee delegation transaction.

feePayer

string

(optional) The address of the fee payer paying the transaction fee. When feeDelegation is true, the value is set to the feePayer field in the transaction.

feeRatio

string

NOTE feeDelegation, feePayer and feeRatio are supported since caver-js v1.6.1.

Example

> myContract.options
{
  address: [Getter/Setter],
  jsonInterface: [Getter/Setter],
  from: [Getter/Setter],
  feePayer: [Getter/Setter],
  feeDelegation: [Getter/Setter],
  feeRatio: [Getter/Setter],
  gasPrice: [Getter/Setter],
  gas: [Getter/Setter],
  data: [Getter/Setter]
}

> myContract.options.from = '0x1234567890123456789012345678901234567891' // default from address
> myContract.options.gasPrice = '25000000000000' // default gas price in peb
> myContract.options.gas = 5000000 // provide as fallback always 5M gas
> myContract.options.feeDelegation = true // use fee delegation transaction
> myContract.options.feePayer = '0x1234567890123456789012345678901234567891' // default fee payer address
> myContract.options.feeRatio = 20 // default fee ratio when send partial fee delegation transaction

myContract.options.address

myContract.options.address

The address used for this contract instance myContract. All transactions generated by caver-js from this contract will contain this address as the to of the transaction.

Property

Name

Type

Description

address

string | null

The address for this contract or null if it is not yet set.

Example

>  myContract.options.address
'0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae'

// set a contract address
>  myContract.options.address = '0x1234FFDD...'

myContract.options.jsonInterface

myContract.options.jsonInterface

The JSON interface object derived from the ABI of this contract myContract.

Property

Name

Type

Description

jsonInterface

Array

The JSON interface for this contract. Re-setting this will regenerate the methods and events of the contract instance.

Example

> myContract.options.jsonInterface
[
  {
    constant: true,
    inputs: [ { name: 'interfaceId', type: 'bytes4' } ],
    name: 'supportsInterface',
    outputs: [ { name: '', type: 'bool' } ],
    payable: false,
    stateMutability: 'view',
    type: 'function',
    signature: '0x01ffc9a7',
  },
  ...
  {
    anonymous: false,
    inputs: [
      { indexed: true, name: 'owner', type: 'address' },
      { indexed: true, name: 'spender', type: 'address' },
      { indexed: false, name: 'value', type: 'uint256' }
    ],
    name: 'Approval',
    type: 'event',
    signature: '0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925',
  },
]

// set a new jsonInterface
> myContract.options.jsonInterface = [...]

myContract.clone

myContract.clone([contractAddress])

Clones the current contract instance.

Parameters

Name

Type

Description

contractAddress

String

(optional) The address of the new contract. If omitted, it will be set to the address in the original instance (e.g., myContract.options.address).

Return Value

Type

Description

object

The new cloned contract instance.

Example

> myContract.clone()
Contract {
  currentProvider: [Getter/Setter],
  ...
  _keyrings: KeyringContainer { ... }
}

myContract.deploy

myContract.deploy(options, byteCode [, param1 [, param2 [, ...]]])

Deploys the contract to the Klaytn network. After a successful deployment, the promise will be resolved with a new contract instance. Unlike the usability of the existing myContract.deploy function, this function sends a transaction directly to the Klaytn network. You don't need to call send() with the returned object.

NOTE caver.wallet must contains keyring instances corresponding to from and feePayer in options or myContract.options to make signatures.

NOTE myContract.deploy is supported since caver-js v1.6.1.

Parameters

Name

Type

Description

options

object

The options used for sending. See the table in methods.methodName.send for the details.

byteCode

string

The byte code of the contract.

parameters

Mixed

(optional) The parameters that get passed to the constructor on deployment.

Return Value

Promise returning PromiEvent: The promise will be resolved with the new contract instance.

Type

Description

PromiEvent

A promise combined event emitter. It will be resolved when the transaction receipt is available. If send() is called from a myContract.deploy(), then the promise will be resolved with the new contract instance.

For PromiEvent, the following events are available:

transactionHash: it is fired right after the transaction is sent and a transaction hash is available. Its type is string.
receipt: It is fired when the transaction receipt is available. See caver.rpc.klay.getTransactionReceipt for more details. Its type is object.
error: It is fired if an error occurs during sending. On an out-of-gas error, the second parameter is the receipt. Its type is Error.

Example

// Deploy a smart contract without constructor arguments
> myContract.deploy({
      from: '0x{address in hex}',
      gas: 1500000,
  }, '0x{byte code}')
  .on('error', function(error) { ... })
  .on('transactionHash', function(transactionHash) { ... })
  .on('receipt', function(receipt) {
     console.log(receipt.contractAddress) // contains the new contract address
   })
  .then(function(newContractInstance) {
      console.log(newContractInstance.options.address) // instance with the new contract address
  })

// Deploy a smart contract with constructor arguments
> myContract.deploy({
      from: '0x{address in hex}',
      gas: 1500000,
  }, '0x{byte code}', 'keyString', ...)
  .on('error', function(error) { ... })
  .on('transactionHash', function(transactionHash) { ... })
  .on('receipt', function(receipt) {
     console.log(receipt.contractAddress) 
   })
  .then(function(newContractInstance) {
      console.log(newContractInstance.options.address)
  })

// Deploy a smart contract with fee delegation transaction (TxTypeFeeDelegatedSmartContractDeploy)
> myContract.deploy({
      from: '0x{address in hex}',
      feeDelegation: true,
      feePayer: '0x{address in hex}',
      gas: 1500000,
  }, '0x{byte code}')
  .on('error', function(error) { ... })
  .on('transactionHash', function(transactionHash) { ... })
  .on('receipt', function(receipt) {
     console.log(receipt.contractAddress)
   })
  .then(function(newContractInstance) {
      console.log(newContractInstance.options.address)
  })

// Deploy a smart contract with partial fee delegation transaction (TxTypeFeeDelegatedSmartContractDeployWithRatio)
> myContract.deploy({
      from: '0x{address in hex}',
      feeDelegation: true,
      feePayer: '0x{address in hex}',
      feeRatio: 30,
      gas: 1500000,
  }, '0x{byte code}')
  .on('error', function(error) { ... })
  .on('transactionHash', function(transactionHash) { ... })
  .on('receipt', function(receipt) {
     console.log(receipt.contractAddress)
   })
  .then(function(newContractInstance) {
      console.log(newContractInstance.options.address)
  })

myContract.deploy

myContract.deploy(options)

Returns the object used when deploying the smart contract to the Klaytn. You can send the smart contract deploy transaction via calling myContract.deploy({ data, arguments }).send(options). After a successful deployment, the promise will be resolved with a new contract instance.

Parameters

Name

Type

Description

options

object

The options object used for deployment. See the below table to find the description.

The options object can contain the following:

Name

Type

Description

data

string

The byte code of the contract.

arguments

Array

(optional) The arguments that get passed to the constructor on deployment.

Return Value

Type

Description

object

An object in which arguments and functions for contract distribution are defined. See the below table to find the description.

The object contains the following:

Name

Type

Description

arguments

Array

The arguments passed in options.arguments.

send

function

The function that will deploy the contract to the Klaytn. The promise as the result of this function will be resolved with the new contract instance.

sign

function

The function that will sign a smart contract deploy transaction as a sender. The sign function will return signed transaction.

signAsFeePayer

function

The function that will sign a smart contract deploy transaction as a fee payer. The signAsFeePayer function will return signed transaction.

estimateGas

function

The function that will estimate the gas used for the deployment. The execution of this function does not deploy the contract.

encodeABI

function

The function that encodes the ABI of the deployment, which is contract data + constructor parameters. The execution of this function does not deploy the contract.

NOTE myContract.deploy({ data, arguments }).sign(options) and myContract.deploy({ data, arguments }).signAsFeePayer(options) are supported since caver-js v1.6.1.

Example

> myContract.deploy({
      data: '0x12345...',
      arguments: [123, 'My string']
  })
  .send({
      from: '0x1234567890123456789012345678901234567891',
      gas: 1500000,
      value: 0,
  }, function(error, transactionHash) { ... })
  .on('error', function(error) { ... })
  .on('transactionHash', function(transactionHash) { ... })
  .on('receipt', function(receipt) {
     console.log(receipt.contractAddress) // contains the new contract address
   })
  .then(function(newContractInstance) {
      console.log(newContractInstance.options.address) // instance with the new contract address
  })

// When the data is already set as an option to the contract itself
> myContract.options.data = '0x12345...'

> myContract.deploy({
        arguments: [123, 'My string']
  })
  .send({
      from: '0x1234567890123456789012345678901234567891',
      gas: 1500000,
      value: 0,
  })
  .then(function(newContractInstance) {
      console.log(newContractInstance.options.address) // instance with the new contract address
  })

// Simply encoding
> myContract.deploy({
      data: '0x12345...',
      arguments: [123, 'My string']
  })
  .encodeABI()
'0x12345...0000012345678765432'

// Gas estimation
> myContract.deploy({
      data: '0x12345...',
      arguments: [123, 'My string']
  })
  .estimateGas(function(err, gas) {
      console.log(gas)
  })

myContract.send

myContract.send(options, methodName [, param1 [, param2 [, ...]]])

Submits a transaction to execute the function of the smart contract. This can alter the smart contract state.

The transaction type used for this function depends on the options or the value defined in myContract.options. If you want to use a fee-delegated transaction through myContract.send, feeDelegation and feePayer should be set properly.

feeDelegation is not defined or defined to false: SmartContractExecution
feeDelegation is defined to true, but feePayer is not defined : Throws an error.
feeDelegation is defined to true and feePayer is defined, but feeRatio is not defined: FeeDelegatedSmartContractExecution
feeDelegation is defined to true and feePayer and feeRatio are defined: FeeDelegatedSmartContractExecutionWithRatio

NOTE caver.wallet must contains keyring instances corresponding to from and feePayer in options or myContract.options to make signatures.

NOTE myContract.send is supported since caver-js v1.6.1.

Parameters

Name

Type

Description

options

object

The options used for sending. See the table in methods.methodName.send for the details.

methodName

string

The method name of the contract function to execute.

parameters

Mixed

(optional) The parameters that get passed to the smart contract function.

Return Value

Promise returns PromiEvent

Type

Description

PromiEvent

A promise combined event emitter. It will be resolved when the transaction receipt is available. The promise will be resolved with the new contract instance.

For PromiEvent, the following events are available:

transactionHash: It is fired right after the transaction is sent and a transaction hash is available. Its type is string.
receipt: It is fired when the transaction receipt is available. See caver.rpc.klay.getTransactionReceipt for more details. Its type is object.
error: It is fired if an error occurs during sending. On an out-of-gas error, the second parameter is the receipt. Its type is Error.

Example

// Send a SmartContractExecution and use the promise
> myContract.send({ from: '0x{address in hex}', gas: 1000000 }, 'methodName', 123).then(console.log)
{
  blockHash: '0x294202dcd1d3c422880e2a209b9cd70ce7036300536c78ab74130c5717cb90da',
  blockNumber: 16342,
  contractAddress: null,
  from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  gas: '0xf4240',
  gasPrice: '0x5d21dba00',
  gasUsed: 47411,
  input: '0x983b2...',
  logsBloom: '0x00800...',
  nonce: '0x1cd',
  senderTxHash: '0xe3f50d2bab2c462ef99379860d2b634d85a0c9fba4e2b189daf1d96bd4bbf8ff',
  signatures: [ { V: '0x4e43', R: '0x2ba27...', S: '0x50d37...' } ],
  status: true,
  to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
  transactionHash: '0xe3f50d2bab2c462ef99379860d2b634d85a0c9fba4e2b189daf1d96bd4bbf8ff',
  transactionIndex: 0,
  type: 'TxTypeSmartContractExecution',
  typeInt: 48,
  value: '0x0',
  events: {...}
}

// Send a SmartContractExecution and use the event emitter
> myContract.send({ from: '0x{address in hex}', gas: 1000000 }, 'methodName', 123)
  .on('transactionHash', function(hash) {
    ...
  })
  .on('receipt', function(receipt) {
    console.log(receipt)
  })
  .on('error', console.error)

// Send a FeeDelegatedSmartContractExecution
> myContract.send({
    from: '0x{address in hex}',
    gas: 1000000,
    feeDelegation: true,
    feePayer: '0x{address in hex}',
  }, 'methodName', 123).then(console.log)
{
  blockHash: '0x149e36f279577c306fccb9779a0274e802501c32f7054c951f592778bd5c168a',
  blockNumber: 16458,
  contractAddress: null,
  feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  feePayerSignatures: [ { V: '0x4e43', R: '0x48c28...', S: '0x18413...' } ],
  from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  gas: '0xf4240',
  gasPrice: '0x5d21dba00',
  gasUsed: 57411,
  input: '0x983b2d5600000000000000000000000022bb89bd35e7b12bd25bea4165cf0f9330032f8c',
  logsBloom: '0x00800...',
  nonce: '0x1f5',
  senderTxHash: '0x5b06ca5046229e066c11dfc0c74fcbc98509294370981f9b142378a8f2bd5fe8',
  signatures: [ { V: '0x4e44', R: '0xfb707...', S: '0x641c6...' } ],
  status: true,
  to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
  transactionHash: '0x0e04be479ad06ec87acbf49abd44f16a56390c736f0a7354860ebc7fc0f92e13',
  transactionIndex: 1,
  type: 'TxTypeFeeDelegatedSmartContractExecution',
  typeInt: 49,
  value: '0x0',
  events: {...}
}

// Send a FeeDelegatedSmartContractExecutionWithRatio
> myContract.send({
    from: '0x{address in hex}',
    gas: 1000000,
    feeDelegation: true,
    feePayer: '0x{address in hex}',
    feeRatio: 30,
  }, 'methodName', 123).then(console.log)
{
  blockHash: '0x8f0a0137cf7e0fea503c818910140246437db36121871bc54b2ebc688873b3f3',
  blockNumber: 16539,
  contractAddress: null,
  feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  feePayerSignatures: [ { V: '0x4e43', R: '0x80db0...', S: '0xf8c7c...' } ],
  feeRatio: '0x1e',
  from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  gas: '0xf4240',
  gasPrice: '0x5d21dba00',
  gasUsed: 62411,
  input: '0x983b2d560000000000000000000000007ad1a538041fa3ba1a721f87203cb1a3822b8eaa',
  logsBloom: '0x00800...',
  nonce: '0x219',
  senderTxHash: '0x14c7b674a0e253b31c85c7be8cbfe4bf9d86e66e940fcae34b854e25eab1ce15',
  signatures: [ { V: '0x4e43', R: '0xd57ef...', S: '0xe14f3...' } ],
  status: true,
  to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
  transactionHash: '0xfbf00ec189aeb0941d554384f1660ffdac7768b3af2bb1526bcb3983215c1183',
  transactionIndex: 0,
  type: 'TxTypeFeeDelegatedSmartContractExecutionWithRatio',
  typeInt: 50,
  value: '0x0',
  events: {...}
}

myContract.sign

myContract.sign(options, methodName [, param1 [, param2 [, ...]]])

Signs a smart contract transaction as a sender to deploy the smart contract or execute the function of the smart contract.

If a smart contract is deployed, 'constructor' can be entered in the methodName, such as myContract.sign({ from, ... }, 'constructor', byteCode, ...).

feeDelegation is not defined or defined to false: SmartContractDeploy / SmartContractExecution
feeDelegation is defined to true, but feeRatio is not defined: FeeDelegatedSmartContractDeploy / FeeDelegatedSmartContractExecution
feeDelegation is defined to true and feeRatio is defined: FeeDelegatedSmartContractDeployWithRatio / FeeDelegatedSmartContractExecutionWithRatio

NOTE caver.wallet must contains keyring instances corresponding to from in options or myContract.options to make signatures.

NOTE myContract.sign is supported since caver-js v1.6.1.

Parameters

Name

Type

Description

options

object

The options used for sending. See the table in methods.methodName.send for the details.

methodName

string

The method name of the contract function to execute. If you want to sign a transaction for deploying the smart contract, use 'constructor' string instead of method name.

parameters

Mixed

(optional) The parameters that get passed to the smart contract function. If you want to sign a smart contract deploy transaction, pass the byteCode and constructor parameters.

Return Value

Promise returning Transaction - The signed smart contract transaction.

Example

// Sign a SmartContractDeploy
> myContract.sign({ from: '0x{address in hex}', gas: 1000000 }, 'constructor', byteCode, 123).then(console.log)
SmartContractDeploy {
  _type: 'TxTypeSmartContractDeploy',
  _from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _gas: '0xf4240',
  _signatures: [ SignatureData { _v: '0x4e43', _r: '0xeb6b5...', _s: '0x5e4f9...' } ],
  _to: '0x',
  _value: '0x0',
  _input: '0x60806...',
  _humanReadable: false,
  _codeFormat: '0x0',
  _chainId: '0x2710',
  _gasPrice: '0x5d21dba00',
  _nonce: '0x2a5'
}

// Sign a FeeDelegatedSmartContractDeploy
> myContract.sign({ from: '0x{address in hex}', feeDelegation: true, gas: 1000000 }, 'constructor', byteCode, 123).then(console.log)
FeeDelegatedSmartContractDeploy {
  _type: 'TxTypeFeeDelegatedSmartContractDeploy',
  _from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _gas: '0xf4240',
  _signatures: [ SignatureData { _v: '0x4e43', _r: '0xee0f5...', _s: '0x31cbf...' } ],
  _feePayer: '0x0000000000000000000000000000000000000000',
  _feePayerSignatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
  _to: '0x',
  _value: '0x0',
  _input: '0x60806...',
  _humanReadable: false,
  _codeFormat: '0x0',
  _chainId: '0x2710',
  _gasPrice: '0x5d21dba00',
  _nonce: '0x320'
}

// Sign a FeeDelegatedSmartContractDeployWithRatio
> myContract.sign({ from: keyring.address, feeDelegation: true, feeRatio: 30, gas: 1000000 }, 'constructor', byteCode, 123).then(console.log)
FeeDelegatedSmartContractDeployWithRatio {
  _type: 'TxTypeFeeDelegatedSmartContractDeployWithRatio',
  _from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _gas: '0xf4240',
  _signatures: [ SignatureData { _v: '0x4e44', _r: '0x4c2b0...', _s: '0x47df8...' } ],
  _feePayer: '0x0000000000000000000000000000000000000000',
  _feePayerSignatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
  _feeRatio: '0x1e',
  _to: '0x',
  _value: '0x0',
  _input: '0x60806...',
  _humanReadable: false,
  _codeFormat: '0x0',
  _chainId: '0x2710',
  _gasPrice: '0x5d21dba00',
  _nonce: '0x306'
}

// Sign a SmartContractExecution
> myContract.sign({ from: '0x{address in hex}', gas: 1000000 }, 'methodName', 123).then(console.log)
SmartContractExecution {
  _type: 'TxTypeSmartContractExecution',
  _from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _gas: '0xf4240',
  _signatures: [ SignatureData { _v: '0x4e44', _r: '0xb2846...', _s: '0x422c1...' } ],
  _to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
  _value: '0x0',
  _input: '0x983b2...',
  _chainId: '0x2710',
  _gasPrice: '0x5d21dba00',
  _nonce: '0x23b'
}

// Sign a FeeDelegatedSmartContractExecution
> myContract.sign({
    from: '0x{address in hex}',
    gas: 1000000,
    feeDelegation: true,
  }, 'methodName', 123).then(console.log)
FeeDelegatedSmartContractExecution {
  _type: 'TxTypeFeeDelegatedSmartContractExecution',
  _from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _gas: '0xf4240',
  _signatures: [ SignatureData { _v: '0x4e43', _r: '0xf7676...', _s: '0x42673...' } ],
  _feePayer: '0x0000000000000000000000000000000000000000',
  _feePayerSignatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
  _to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
  _value: '0x0',
  _input: '0x983b2...',
  _chainId: '0x2710',
  _gasPrice: '0x5d21dba00',
  _nonce: '0x254'
}

// Sign a FeeDelegatedSmartContractExecutionWithRatio
> myContract.sign({
    from: '0x{address in hex}',
    gas: 1000000,
    feeDelegation: true,
    feeRatio: 30,
  }, 'methodName', 123).then(console.log)
FeeDelegatedSmartContractExecutionWithRatio {
  _type: 'TxTypeFeeDelegatedSmartContractExecutionWithRatio',
  _from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _gas: '0xf4240',
  _signatures: [ SignatureData { _v: '0x4e44', _r: '0x58b06...', _s: '0x637ff...' } ],
  _feePayer: '0x0000000000000000000000000000000000000000',
  _feePayerSignatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
  _feeRatio: '0x1e',
  _to: '0x361870b50834a6afc3358e81a3f7f1b1eb9c7e55',
  _value: '0x0',
  _input: '0x983b2...',
  _chainId: '0x2710',
  _gasPrice: '0x5d21dba00',
  _nonce: '0x262'
}

myContract.signAsFeePayer

myContract.signAsFeePayer(options, methodName [, param1 [, param2 [, ...]]])

Signs a smart contract transaction as a fee payer to deploy the smart contract or execute the function of the smart contract.

If a smart contract is deployed, 'constructor' can be entered in the methodName, such as myContract.signAsFeePayer({ from, feeDelegation: true, feePayer, ... }, 'constructor', byteCode, ...).

The transaction type used for this function depends on the options or the value defined in myContract.options. The signAsFeePayer is a function that signs as a transaction fee payer, so feeDelegation field must be defined as true. Also, the address of the fee payer must be defined in the feePayer field.

feeDelegation is not defined : Throws an error.
feeDelegation is defined, but feePayer is not defined : Throws an error.
feeDelegation is defined to true and feePayer is defined, but feeRatio is not defined: FeeDelegatedSmartContractDeploy / FeeDelegatedSmartContractExecution
feeDelegation is defined to true and feePayer and feeRatio are defined: FeeDelegatedSmartContractDeployWithRatio / FeeDelegatedSmartContractExecutionWithRatio

NOTE caver.wallet must contains keyring instances corresponding to feePayer in options or myContract.options to make signatures.

NOTE myContract.signAsFeePayer is supported since caver-js v1.6.1.

Parameters

Name

Type

Description

options

object

The options used for sending. See the table in methods.methodName.send for the details.

methodName

string

The method name of the contract function to execute. If you want to sign a transaction for deploying the smart contract, use 'constructor' string instead of method name.

parameters

Mixed

(optional) The parameters that get passed to the smart contract function. If you want to sign a smart contract deploy transaction, pass the byteCode and constructor parameters.

Return Value

Promise returning Transaction - The signed smart contract transaction.

Example

// Sign a FeeDelegatedSmartContractDeploy
> myContract.signAsFeePayer({ from: '0x{address in hex}', feeDelegation: true, feePayer: '0x{address in hex}', gas: 1000000 }, 'constructor', byteCode, 123).then(console.log)
FeeDelegatedSmartContractDeploy {
  _type: 'TxTypeFeeDelegatedSmartContractDeploy',
  _from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _gas: '0xf4240',
  _signatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
  _feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _feePayerSignatures: [ SignatureData { _v: '0x4e43', _r: '0xe0641...', _s: '0x1d21e...' } ],
  _to: '0x',
  _value: '0x0',
  _input: '0x60806...',
  _humanReadable: false,
  _codeFormat: '0x0',
  _chainId: '0x2710',
  _gasPrice: '0x5d21dba00',
  _nonce: '0x32a'
}

// Sign a FeeDelegatedSmartContractDeployWithRatio
> myContract.signAsFeePayer({ from: keyring.address, feeDelegation: true, feePayer: '0x{address in hex}', feeRatio: 30, gas: 1000000 }, 'constructor', byteCode, 123).then(console.log)
FeeDelegatedSmartContractDeployWithRatio {
  _type: 'TxTypeFeeDelegatedSmartContractDeployWithRatio',
  _from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _gas: '0xf4240',
  _signatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
  _feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _feePayerSignatures: [ SignatureData { _v: '0x4e44', _r: '0x307bd...', _s: '0x75110...' } ],
  _feeRatio: '0x1e',
  _to: '0x',
  _value: '0x0',
  _input: '0x60806...',
  _humanReadable: false,
  _codeFormat: '0x0',
  _chainId: '0x2710',
  _gasPrice: '0x5d21dba00',
  _nonce: '0x359'
}

// Sign a FeeDelegatedSmartContractExecution
> myContract.signAsFeePayer({
    from: '0x{address in hex}',
    gas: 1000000,
    feeDelegation: true,
    feePayer: '0x{address in hex}',
  }, 'methodName', 123).then(console.log)
FeeDelegatedSmartContractExecution {
  _type: 'TxTypeFeeDelegatedSmartContractExecution',
  _from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _gas: '0xf4240',
  _signatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
  _feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _feePayerSignatures: [ SignatureData { _v: '0x4e43', _r: '0xc58ba...', _s: '0x76fdb...' } ],
  _to: '0x4a9d979707aede18fa674711f3b2fe110fac4e7e',
  _value: '0x0',
  _input: '0x983b2...',
  _chainId: '0x2710',
  _gasPrice: '0x5d21dba00',
  _nonce: '0x36c'
}

// Sign a FeeDelegatedSmartContractExecutionWithRatio
> myContract.signAsFeePayer({
    from: '0x{address in hex}',
    gas: 1000000,
    feeDelegation: true,
    feePayer: '0x{address in hex}',
    feeRatio: 30,
  }, 'methodName', 123).then(console.log)
FeeDelegatedSmartContractExecutionWithRatio {
  _type: 'TxTypeFeeDelegatedSmartContractExecutionWithRatio',
  _from: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _gas: '0xf4240',
  _signatures: [ SignatureData { _v: '0x01', _r: '0x', _s: '0x' } ],
  _feePayer: '0x69c3a6e3485446118d8081063dcef2e65b69ae91',
  _feePayerSignatures: [ SignatureData { _v: '0x4e44', _r: '0xeb78d...', _s: '0x2864d...' } ],
  _feeRatio: '0x1e',
  _to: '0x4a9d979707aede18fa674711f3b2fe110fac4e7e',
  _value: '0x0',
  _input: '0x983b2...',
  _chainId: '0x2710',
  _gasPrice: '0x5d21dba00',
  _nonce: '0x37b'
}

myContract.call

myContract.call('methodName', [param1 [, param2 [, ...]]])
myContract.call(options, 'methodName', [param1 [, param2 [, ...]]])

Will call a constant method and execute its smart contract method in the Klaytn Virtual Machine without sending any transaction. Note that calling cannot alter the smart contract state.

NOTE myContract.call is supported since caver-js v1.6.1.

Parameters

Name

Type

Description

options

object

(optional) The options used for calling. See the table in methods.methodName.call for the details.

methodName

string

The method name of the contract function to call.

parameters

Mixed

(optional) The parameters that get passed to the smart contract function.

Return Value

Promise returning Mixed - The return value(s) of the smart contract method. If it returns a single value, it is returned as it is. If it has multiple return values, it returns an object with properties and indices.

Example

> myContract.call('methodName').then(console.log)
Jasmine

> myContract.call({ from: '0x{address in hex}' }, 'methodName', 123).then(console.log)
Test Result

myContract.decodeFunctionCall

myContract.decodeFunctionCall(functionCall)

Decodes a function call and returns parameters.

NOTE myContract.decodeFunctionCall is supported since caver-js v1.6.3.

Parameters

Name

Type

Description

functionCall

string

The encoded function call string.

Return Value

Type

Description

object

An object which includes plain params. You can use result[0] as it is provided to be accessed like an array in the order of the parameters.

Examples

// The myContract variable is instantiated with the below abi.
// [
//   {
//     constant: true,
//     inputs: [{ name: 'key', type: 'string' }],
//     name: 'get',
//     outputs: [{ name: '', type: 'string' }],
//     payable: false,
//     stateMutability: 'view',
//     type: 'function',
//   },
//   {
//     constant: false,
//     inputs: [{ name: 'key', type: 'string' }, { name: 'value', type: 'string' }],
//     name: 'set',
//     outputs: [],
//     payable: false,
//     stateMutability: 'nonpayable',
//     type: 'function',
//   },
// ]
> myContract.decodeFunctionCall('0xe942b5160000000000000000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000036b65790000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000576616c7565000000000000000000000000000000000000000000000000000000')
Result {
  '0': '2345675643',
  '1': 'Hello!%',
  __length__: 2,
  myNumber: '2345675643',
  mystring: 'Hello!%'
}

myContract.methods

myContract.methods.methodName([param1 [, param2 [, ...]]])
myContract.methods['methodName']([param1 [, param2 [, ...]]])

Creates a transaction object for that method, which then can be called, sent, estimated or ABI encoded.

The methods of this smart contract are available via:

Method name: myContract.methods.methodName(123) or myContract.methods[methodName](123)
Method prototype: myContract.methods['methodName(uint256)'](123)
Method signature: myContract.methods['0x58cf5f10'](123)

This allows calling functions with the same name but different parameters from the JavaScript contract object.

cf) *function signature (function selector)

The first four bytes of the call data for a function call specifies the function to be called. It is the first (left, high-order in big-endian) four bytes of the Keccak-256 (SHA-3) hash of the signature of the function.

The function signature can be given via 2 different methods. 1. caver.abi.encodefunctionSignature('funcName(paramType1,paramType2,...)') 2. caver.utils.sha3('funcName(paramType1,paramType2,...)').substr(0, 10)

ex)

caver.abi.encodefunctionSignature('methodName(uint256)')
> 0x58cf5f10

caver.utils.sha3('methodName(uint256)').substr(0, 10)
> 0x58cf5f10

Parameters

Parameters of any method that belongs to this smart contract, defined in the JSON interface.

Return Value

Promise returning object - An object in which arguments and functions for contract execution are defined.:

Name

Type

Description

arguments

Array

The arguments passed to this method.

call

function

The function that will call and execute a constant method in its smart contract on Klaytn Virtual Machine without sending a transaction (cannot alter the smart contract state).

send

function

The function that will send a transaction to the Klaytn and execute its method (can alter the smart contract state).

sign

function

The function that will sign a transaction as a sender. The sign function will return signed transaction.

signAsFeePayer

function

The function that will sign a transaction as a fee payer. The signAsFeePayer function will return signed transaction.

estimateGas

function

The that function will estimate the gas used for the execution.

encodeABI

function

The function that encodes the ABI for this method. This can be sent using a transaction, calling the method, or passing into another smart contract method as its argument.

NOTE sign and signAsFeePayer are supported since caver-js v1.6.1.

Example

// Calling a method
> myContract.methods.methodName(123).call({ ... }, function(error, result) { ... })
> myContract.methods.methodName(123).call({ ... }).then((result) => { ... })

// Sending basic transaction and using the promise
> myContract.methods.methodName(123).send({
    from: '0x{address in hex}',
    ...
  }).then(function(receipt) {