# Zilliqa API "contract".

# `window.zilPay.contracts`

Object for managing Scilla smart contracts on the Zilliqa blockchain.

# Static Methods:

static getAddressForContract(tx: Transaction): string

Computes the address for a contract deployment by concatenating senderAddress and nonce and hasing the resulting bytes. Note that this method will not compute an accurate address if the provided nonce is not up to date with the actual nonce on the blockchain.

Parameters

tx: Transaction - a Transaction with nonce and senderAddress.

Returns

The compute contract address.

# Instance Methods

at(address: string, abi: ABI, code: string, init?: Init, state?: State): Contract

Constructs a Contract with the provided parameters. It is recommended that this method by used only to construct contracts that have already been deployed.

Parameters

address: string - the contract address.
abi: ABI (optional) - the ABI return by scilla-checker.
code: string (optional) - UTF-8 encoded Scilla smart contract code.
init: Init (optional) - the initialisation parameters of the smart contract.
state: State (optional) - the current smart contract state.

Returns

Contract - a Contract instance.

new(code: string, init: Init, abi?: ABI): Contract

Constructs a Contract with the provided parameters, that is not deployed. The contract may subsequently be deployed.

Parameters

code: string - UTF-8 encoded Scilla smart contract code.
init: Init - the initialisation parameters of the smart contract.
abi: ABI (optional) - the ABI return by scilla-checker.

Returns

Contract - a Contract instance.

Contract(factory: Contracts, code?: string, address?: string, abi?: ABI, init?: Init, state?: State): Contracts

A class representing a single smart contract. Allows for deployment and calling the smart contract's transitions. This class is still under development, and its API should, as of now, be considered unstable and a candidate for breaking changes prior to the launch of the Zilliqa main net.

Parameters

factory: Contracts - the creating factory instance.
code: string (Optional) - UTF-8 Scilla smart contract code.
address: string (Optional)
init: any (Optional) - contract initialisation parameters.
state: any (Optional) - contract state.

Returns

Contract - a Contract instance.

# Instance Methods

isInitialised(): boolean

Returns true if no attempt has been made to deploy the Contract, or its status is unknown.

Returns

boolean

isDeployed(): boolean

Returns true if the contract has been successfully deployed.

Returns

boolean

isRejected(): boolean

Returns true if the contract deployment attempt was rejected by the network.

Returns

boolean

deploy(params: DeployParams, attempts: number = 33, interval: number = 1000): Promise<Contract>

Deploys a contract to the blockchain. This method will automatically generate and sign the underlying Transaction and broadcast it. The status of the Contract may then be ascertained by using isRejected or isDeployed, once the Promise resolves.

This API is unstable and subject to breaking changes pre-main net

Parameters

params: DeployParams - a subset of TxParams. Passed to the underlying Transaction. This can be used to manually provide nonce and pubKey, if it is desirable to sign the underlying transaction with a non-default account in the Wallet.
attempts (Optional - default 33): number - the number of times to poll the lookup node for transaction receipt.
interval (Optional - default 1000): number - the amount of time to wait between attempts. increases linearly (numAttempts * interval).

Returns

Promise<Contract> - will be rejected if a network error occurs. A resolved Promise does not indicate that the Contract is deployed, as the underlying Transaction may be confirmed by the blockchain but unsuccessful, due to lack of gas, and so on.

call(transition: string, args: Value[], params: CallParams): Promise<Transaction>

Calls a transition of the current contract. At the moment, this is a low-level interface for interacting with simple smart contracts.

This API is unstable and subject to breaking changes pre-main net

Parameters

transition: string - the exact name of the contract transition to be invoked. case matters
args: Value[] - JSON-encoded array of transition arguments.
params: CallParams - a subset of TxParams. Passed to the underlying Transaction.
attempts (Optional - default 20): number - the number of times to poll the lookup node for transaction receipt.
interval (Optional - default 1000): number - the amount of time to wait between attempts. increases linearly (numAttempts * interval).

Returns

Promise<Transaction> - the Transaction that has been signed and broadcast to the network.

getState(): Promise<State>

Queries the blockchain for the smart contract's state. Note that this method will return the entire state of the smart contract. As a result, if you have a large amount of data stored in a smart contract do not use this method on a client. Instead, use a server-side layer to cache and proxy such queries.

This API is temporary and will be subject to breaking changes

Parameters

None

Returns

Promise<State> - the Contract state.

# Examples:

method at: create contract instance by contract address.

// Create contract instance with some methods
const contract = zilPay
  .contracts
  .at('zil1az5e0c6e4s4pazgahhmlca2cvgamp6kjtaxf4q');

contract.getCode().then(({ code }) => /do something.../)
contract.getInit().then((init) => /do something.../)
contract.getState().then((contractState) => /do something.../)
contract.getSubState('entropy').then(({ entropy }) => /do something.../)

method new: create new contract by code.

const scillaCode = `scilla_version 0
import ListUtils
library HelloWorld

let one_msg = 
  fun (msg : Message) => 
  let nil_msg = Nil {Message} in
  Cons {Message} msg nil_msg
  
let not_owner_code = Int32 1
let set_hello_code = Int32 2

contract HelloWorld
(owner: ByStr20)

field welcome_msg : String = ""

transition setHello (msg : String)
  is_owner = builtin eq owner _sender;
  match is_owner with
  | False =>
    e = {_eventname : "setHello()"; code : not_owner_code};
    event e
  | True =>
    welcome_msg := msg;
    e = {_eventname : "setHello()"; code : set_hello_code};
    event e
  end
end

transition getHello ()
    r <- welcome_msg;
    e = {_eventname: "getHello()"; msg: r};
    event e
end

transition multipleMsgs()
  msg1 = {_tag : ""; _recipient : _sender; _amount : Uint128 0};
  msg2 = {_tag : ""; _recipient : _sender; _amount : Uint128 0};
  msgs1 = one_msg msg1;
  msgs2 = Cons {Message} msg2 msgs1;
  send msgs2
end

transition contrAddr()
  msg1 = {_eventname : "ContractAddress"; addr : _this_address };
  event msg1
end
`
const init = [
  {
    "vname":"owner",
    "type":"ByStr20",
    "value":"zil1zxvjnkxr3r0rv582rv7u0w07pnh0ap30td4thr"
  },
  {
    "vname":"_scilla_version",
    "type":"Uint32",
    "value":"0"
  }
]
// Create contract instance with some methods
const contract = zilPay
  .contracts
  .new(scillaCode, init);

// Sending to DS
contract.deploy({
  gasLimit: '25000',
  gasPrice: '1000000000'
}, true)
.then(([tx, contract]) => /do something.../);

// Sending to TX
contract.deploy({
  gasLimit: '25000',
  gasPrice: '1000000000'
})
.then(([tx, contract]) => /do something.../);

method at: create contract instance by contract address.

// Create contract instance with some methods
const contract = zilPay
  .contracts
  .at('zil1az5e0c6e4s4pazgahhmlca2cvgamp6kjtaxf4q');

contract.getCode().then(({ code }) => /do something.../)
contract.getInit().then((init) => /do something.../)
contract.getState().then((contractState) => /do something.../)
contract.getSubState('entropy').then(({ entropy }) => /do something.../)

method call: create new contract by code.

const { contracts, utils, wallet } = window.zilPay;
const contract = contracts.at(this.contractAddress);
const amount = utils.units.toQa(0, utils.units.Units.Zil);
const gasPrice = utils.units.toQa('1000', utils.units.Units.Li)

// Sending to DS
const tx = await contract.call(
  'setHello',
  [
    {
      vname: 'msg',
      type: 'String',
      value: 'TEST'
    }
  ],
  {
    amount,
    gasPrice,
    gasLimit: utils.Long.fromNumber(9000)
  },
  true
).then(([tx, contract]) => /do something.../);

// Sending to TX
const tx = await contract.call(
  'setHello',
  [
    {
      vname: 'msg',
      type: 'String',
      value: 'TEST'
    }
  ],
  {
    amount,
    gasPrice,
    gasLimit: utils.Long.fromNumber(9000)
  }
).then(([tx, contract]) => /do something.../);

← Zilliqa API "utils".

# Zilliqa API "contract".

# window.zilPay.contracts

# Static Methods:

# Instance Methods

# Instance Methods

# Examples:

# `window.zilPay.contracts`