@zilliqa-js/contract

@zilliqa-js/contract

Classes for managing Scilla smart contracts on the Zilliqa blockchain.

Interfaces

interface DeployParams {
  gasPrice: BN;
  gasLimit: Long;
  nonce?: number;
  pubKey?: string;
}

interface CallParams {
  amount: BN;
  gasPrice: BN;
  gasLimit: Long;
  nonce?: number;
  pubKey?: string;
}

interface Field {
  name: string;
  type: string;
}

interface Transition {
  name: string;
  params: Field[];
}

interface ABI {
  name: string;
  fields: Field[];
  params: Field[];
  transitions: Transition[];
}

interface Value {
  vname: string;
  type: string;
  value: string;
}

type Init = Value[];
type State = any;

Classes

Contracts

A factory class for creating Contract instances. Useful for managing Provider instances set on Contracts. The factory is mainly used by the top-level module exported by @zilliqa-js/zilliqa.

Contracts(provider: Provider, signer?: Wallet): Contracts

Parameters

• provider: Provider - a Provider instance
• signer: Wallet - a Wallet instance, used for signing transactions.

Returns

• Contracts - a Contracts instance.

Members

provider: Provider

signer: Wallet

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 with -contractinfo flag.
• 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.

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.
• abi: string (Optional) - scilla interface

Returns

• Contract - a Contract instance.

Members

factory: Contracts provider: Provider signer: Wallet

init: Init abi?: ABI (Optional) state?: State (Optional) address?: string (Optional) code?: string (Optional) status: ContractStatus

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.

Parameters

None

Returns

• Promise<State> - the Contract state.

getInit(): Promise<State>

Queries the blockchain for the smart contract's init (a.k.a. immutable variables of a contract)

Parameters

None

Returns

• Promise<State> - the Contract Init.

getSubState(variableName: string, indices: string[]): Promise<State>

Queries the contract state, filtered by the variable names. This function is the filtered version of getState. As getSubState performs the filtering, variableName of a field is required.

If the subState is not found, this returns a null response.

Parameters

• variableName: string - the variable name within a state
• indices : string[] - optional variable. If the variableName is a Map, an array of indices may be provided. See examples/ to see how to use this method.

Returns

• Promise<State> - the Contract Init.