import { schemas, SchemaValidator } from '@0xproject/json-schemas'; import { AbiType, ContractAbi, EventAbi, FunctionAbi, MethodAbi, TxData } from '@0xproject/types'; import { promisify } from '@0xproject/utils'; import * as _ from 'lodash'; import * as Web3 from 'web3'; export class Contract implements Web3.ContractInstance { public address: string; public abi: ContractAbi; private _contract: Web3.ContractInstance; private _defaults: Partial; private _validator: SchemaValidator; // This class instance is going to be populated with functions and events depending on the ABI // and we don't know their types in advance [name: string]: any; constructor(web3ContractInstance: Web3.ContractInstance, defaults: Partial) { this._contract = web3ContractInstance; this.address = web3ContractInstance.address; this.abi = web3ContractInstance.abi; this._defaults = defaults; this._populateEvents(); this._populateFunctions(); this._validator = new SchemaValidator(); } private _populateFunctions(): void { const functionsAbi = _.filter(this.abi, abiPart => abiPart.type === AbiType.Function) as FunctionAbi[]; _.forEach(functionsAbi, (functionAbi: MethodAbi) => { if (functionAbi.constant) { const cbStyleCallFunction = this._contract[functionAbi.name].call; this[functionAbi.name] = promisify(cbStyleCallFunction, this._contract); this[functionAbi.name].call = promisify(cbStyleCallFunction, this._contract); } else { const cbStyleFunction = this._contract[functionAbi.name]; const cbStyleCallFunction = this._contract[functionAbi.name].call; const cbStyleEstimateGasFunction = this._contract[functionAbi.name].estimateGas; this[functionAbi.name] = this._promisifyWithDefaultParams(cbStyleFunction); this[functionAbi.name].estimateGasAsync = promisify(cbStyleEstimateGasFunction); this[functionAbi.name].sendTransactionAsync = this._promisifyWithDefaultParams(cbStyleFunction); this[functionAbi.name].call = promisify(cbStyleCallFunction, this._contract); } }); } private _populateEvents(): void { const eventsAbi = _.filter(this.abi, abiPart => abiPart.type === AbiType.Event) as EventAbi[]; _.forEach(eventsAbi, (eventAbi: EventAbi) => { this[eventAbi.name] = this._contract[eventAbi.name]; }); } private _promisifyWithDefaultParams(fn: (...args: any[]) => void): (...args: any[]) => Promise { const promisifiedWithDefaultParams = async (...args: any[]) => { const promise = new Promise((resolve, reject) => { const lastArg = args[args.length - 1]; let txData: Partial = {}; if (this._isTxData(lastArg)) { txData = args.pop(); } txData = { ...this._defaults, ...txData, }; const callback = (err: Error, data: any) => { if (_.isNull(err)) { resolve(data); } else { reject(err); } }; args.push(txData); args.push(callback); fn.apply(this._contract, args); }); return promise; }; return promisifiedWithDefaultParams; } private _isTxData(lastArg: any): boolean { const isValid = this._validator.isValid(lastArg, schemas.txDataSchema); return isValid; } }