path: root/packages/web3-wrapper/src/web3_wrapper.ts

import { assert } from '@0xproject/assert';
import { schemas } from '@0xproject/json-schemas';
import { AbiDecoder, addressUtils, BigNumber, intervalUtils, promisify } from '@0xproject/utils';
import {
    BlockParam,
    BlockParamLiteral,
    BlockWithoutTransactionData,
    BlockWithTransactionData,
    CallData,
    FilterObject,
    JSONRPCRequestPayload,
    JSONRPCResponsePayload,
    LogEntry,
    Provider,
    RawLogEntry,
    TraceParams,
    TransactionReceipt,
    TransactionReceiptWithDecodedLogs,
    TransactionTrace,
    TxData,
} from 'ethereum-types';
import * as _ from 'lodash';

import { marshaller } from './marshaller';
import { BlockWithoutTransactionDataRPC, BlockWithTransactionDataRPC, NodeType, Web3WrapperErrors } from './types';
import { utils } from './utils';

const BASE_TEN = 10;

// These are unique identifiers contained in the response of the
// web3_clientVersion call.
const uniqueVersionIds = {
    geth: 'Geth',
    ganache: 'EthereumJS TestRPC',
};

/**
 * An alternative to the Web3.js library that provides a consistent, clean, promise-based interface.
 */
export class Web3Wrapper {
    /**
     * Flag to check if this instance is of type Web3Wrapper
     */
    public isZeroExWeb3Wrapper = true;
    public abiDecoder: AbiDecoder;
    private _provider: Provider;
    private readonly _txDefaults: Partial<TxData>;
    private _jsonRpcRequestId: number;
    /**
     * Check if an address is a valid Ethereum address
     * @param address Address to check
     * @returns Whether the address is a valid Ethereum address
     */
    public static isAddress(address: string): boolean {
        return addressUtils.isAddress(address);
    }
    /**
     * A unit amount is defined as the amount of a token above the specified decimal places (integer part).
     * E.g: If a currency has 18 decimal places, 1e18 or one quintillion of the currency is equivalent
     * to 1 unit.
     * @param   amount      The amount in baseUnits that you would like converted to units.
     * @param   decimals    The number of decimal places the unit amount has.
     * @return  The amount in units.
     */
    public static toUnitAmount(amount: BigNumber, decimals: number): BigNumber {
        assert.isValidBaseUnitAmount('amount', amount);
        assert.isNumber('decimals', decimals);
        const aUnit = new BigNumber(BASE_TEN).pow(decimals);
        const unit = amount.div(aUnit);
        return unit;
    }
    /**
     * A baseUnit is defined as the smallest denomination of a token. An amount expressed in baseUnits
     * is the amount expressed in the smallest denomination.
     * E.g: 1 unit of a token with 18 decimal places is expressed in baseUnits as 1000000000000000000
     * @param   amount      The amount of units that you would like converted to baseUnits.
     * @param   decimals    The number of decimal places the unit amount has.
     * @return  The amount in baseUnits.
     */
    public static toBaseUnitAmount(amount: BigNumber, decimals: number): BigNumber {
        assert.isBigNumber('amount', amount);
        assert.isNumber('decimals', decimals);
        const unit = new BigNumber(BASE_TEN).pow(decimals);
        const baseUnitAmount = amount.times(unit);
        const hasDecimals = baseUnitAmount.decimalPlaces() !== 0;
        if (hasDecimals) {
            throw new Error(`Invalid unit amount: ${amount.toString()} - Too many decimal places`);
        }
        return baseUnitAmount;
    }
    /**
     * Convert an Ether amount from ETH to Wei
     * @param ethAmount Amount of Ether to convert to wei
     * @returns Amount in wei
     */
    public static toWei(ethAmount: BigNumber): BigNumber {
        assert.isBigNumber('ethAmount', ethAmount);
        const ETH_DECIMALS = 18;
        const balanceWei = Web3Wrapper.toBaseUnitAmount(ethAmount, ETH_DECIMALS);
        return balanceWei;
    }
    private static _assertBlockParam(blockParam: string | BlockParam): void {
        if (_.isNumber(blockParam)) {
            return;
        } else if (_.isString(blockParam)) {
            assert.doesBelongToStringEnum('blockParam', blockParam, BlockParamLiteral);
        }
    }
    private static _assertBlockParamOrString(blockParam: string | BlockParam): void {
        try {
            Web3Wrapper._assertBlockParam(blockParam);
        } catch (err) {
            try {
                assert.isHexString('blockParam', blockParam as string);
                return;
            } catch (err) {
                throw new Error(`Expected blockParam to be of type "string | BlockParam", encountered ${blockParam}`);
            }
        }
    }
    private static _normalizeTxReceiptStatus(status: undefined | null | string | 0 | 1): null | 0 | 1 {
        // Transaction status might have four values
        // undefined - Testrpc and other old clients
        // null - New clients on old transactions
        // number - Parity
        // hex - Geth
        if (_.isString(status)) {
            return utils.convertHexToNumber(status) as 0 | 1;
        } else if (_.isUndefined(status)) {
            return null;
        } else {
            return status;
        }
    }
    /**
     * Instantiates a new Web3Wrapper.
     * @param   provider    The Web3 provider instance you would like the Web3Wrapper to use for interacting with
     *                      the backing Ethereum node.
     * @param   txDefaults  Override TxData defaults sent with RPC requests to the backing Ethereum node.
     * @return  An instance of the Web3Wrapper class.
     */
    constructor(provider: Provider, txDefaults?: Partial<TxData>) {
        assert.isWeb3Provider('provider', provider);
        if (_.isUndefined((provider as any).sendAsync)) {
            // Web3@1.0 provider doesn't support synchronous http requests,
            // so it only has an async `send` method, instead of a `send` and `sendAsync` in web3@0.x.x`
            // We re-assign the send method so that Web3@1.0 providers work with @0xproject/web3-wrapper
            (provider as any).sendAsync = (provider as any).send;
        }
        this.abiDecoder = new AbiDecoder([]);
        this._provider = provider;
        this._txDefaults = txDefaults || {};
        this._jsonRpcRequestId = 0;
    }
    /**
     * Get the contract defaults set to the Web3Wrapper instance
     * @return  TxData defaults (e.g gas, gasPrice, nonce, etc...)
     */
    public getContractDefaults(): Partial<TxData> {
        return this._txDefaults;
    }
    /**
     * Retrieve the Web3 provider
     * @return  Web3 provider instance
     */
    public getProvider(): Provider {
        return this._provider;
    }
    /**
     * Update the used Web3 provider
     * @param provider The new Web3 provider to be set
     */
    public setProvider(provider: Provider): void {
        assert.isWeb3Provider('provider', provider);
        this._provider = provider;
    }
    /**
     * Check whether an address is available through the backing provider. This can be
     * useful if you want to know whether a user can sign messages or transactions from
     * a given Ethereum address.
     * @param senderAddress Address to check availability for
     * @returns Whether the address is available through the provider.
     */
    public async isSenderAddressAvailableAsync(senderAddress: string): Promise<boolean> {
        assert.isETHAddressHex('senderAddress', senderAddress);
        const addresses = await this.getAvailableAddressesAsync();
        const normalizedAddress = senderAddress.toLowerCase();
        return _.includes(addresses, normalizedAddress);
    }
    /**
     * Fetch the backing Ethereum node's version string (e.g `MetaMask/v4.2.0`)
     * @returns Ethereum node's version string
     */
    public async getNodeVersionAsync(): Promise<string> {
        const nodeVersion = await this._sendRawPayloadAsync<string>({ method: 'web3_clientVersion' });
        return nodeVersion;
    }
    /**
     * Fetches the networkId of the backing Ethereum node
     * @returns The network id
     */
    public async getNetworkIdAsync(): Promise<number> {
        const networkIdStr = await this._sendRawPayloadAsync<string>({ method: 'net_version' });
        const networkId = _.parseInt(networkIdStr);
        return networkId;
    }
    /**
     * Retrieves the transaction receipt for a given transaction hash
     * @param txHash Transaction hash
     * @returns The transaction receipt, including it's status (0: failed, 1: succeeded or undefined: not found)
     */
    public async getTransactionReceiptAsync(txHash: string): Promise<TransactionReceipt> {
        assert.isHexString('txHash', txHash);
        const transactionReceipt = await this._sendRawPayloadAsync<TransactionReceipt>({
            method: 'eth_getTransactionReceipt',
            params: [txHash],
        });
        if (!_.isNull(transactionReceipt)) {
            transactionReceipt.status = Web3Wrapper._normalizeTxReceiptStatus(transactionReceipt.status);
        }
        return transactionReceipt;
    }
    /**
     * Retrieves an accounts Ether balance in wei
     * @param owner Account whose balance you wish to check
     * @returns Balance in wei
     */
    public async getBalanceInWeiAsync(owner: string, defaultBlock?: BlockParam): Promise<BigNumber> {
        assert.isETHAddressHex('owner', owner);
        if (!_.isUndefined(defaultBlock)) {
            Web3Wrapper._assertBlockParam(defaultBlock);
        }
        const marshalledDefaultBlock = marshaller.marshalBlockParam(defaultBlock);
        const encodedOwner = marshaller.marshalAddress(owner);
        const balanceInWei = await this._sendRawPayloadAsync<string>({
            method: 'eth_getBalance',
            params: [encodedOwner, marshalledDefaultBlock],
        });
        // Rewrap in a new BigNumber
        return new BigNumber(balanceInWei);
    }
    /**
     * Check if a contract exists at a given address
     * @param address Address to which to check
     * @returns Whether or not contract code was found at the supplied address
     */
    public async doesContractExistAtAddressAsync(address: string): Promise<boolean> {
        assert.isETHAddressHex('address', address);
        const code = await this.getContractCodeAsync(address);
        // Regex matches 0x0, 0x00, 0x in order to accommodate poorly implemented clients
        const isCodeEmpty = /^0x0{0,40}$/i.test(code);
        return !isCodeEmpty;
    }
    /**
     * Gets the contract code by address
     * @param  address Address of the contract
     * @param defaultBlock Block height at which to make the call. Defaults to `latest`
     * @return Code of the contract
     */
    public async getContractCodeAsync(address: string, defaultBlock?: BlockParam): Promise<string> {
        assert.isETHAddressHex('address', address);
        if (!_.isUndefined(defaultBlock)) {
            Web3Wrapper._assertBlockParam(defaultBlock);
        }
        const marshalledDefaultBlock = marshaller.marshalBlockParam(defaultBlock);
        const encodedAddress = marshaller.marshalAddress(address);
        const code = await this._sendRawPayloadAsync<string>({
            method: 'eth_getCode',
            params: [encodedAddress, marshalledDefaultBlock],
        });
        return code;
    }
    /**
     * Gets the debug trace of a transaction
     * @param  txHash Hash of the transactuon to get a trace for
     * @param  traceParams Config object allowing you to specify if you need memory/storage/stack traces.
     * @return Transaction trace
     */
    public async getTransactionTraceAsync(txHash: string, traceParams: TraceParams): Promise<TransactionTrace> {
        assert.isHexString('txHash', txHash);
        const trace = await this._sendRawPayloadAsync<TransactionTrace>({
            method: 'debug_traceTransaction',
            params: [txHash, traceParams],
        });
        return trace;
    }
    /**
     * Sign a message with a specific address's private key (`eth_sign`)
     * @param address Address of signer
     * @param message Message to sign
     * @returns Signature string (might be VRS or RSV depending on the Signer)
     */
    public async signMessageAsync(address: string, message: string): Promise<string> {
        assert.isETHAddressHex('address', address);
        assert.isETHAddressHex('address', address);
        assert.isString('message', message); // TODO: Should this be stricter? Hex string?
        const signData = await this._sendRawPayloadAsync<string>({
            method: 'eth_sign',
            params: [address, message],
        });
        return signData;
    }
    /**
     * Fetches the latest block number
     * @returns Block number
     */
    public async getBlockNumberAsync(): Promise<number> {
        const blockNumberHex = await this._sendRawPayloadAsync<string>({
            method: 'eth_blockNumber',
            params: [],
        });
        const blockNumber = utils.convertHexToNumberOrNull(blockNumberHex);
        return blockNumber as number;
    }
    /**
     * Fetch a specific Ethereum block without transaction data
     * @param blockParam The block you wish to fetch (blockHash, blockNumber or blockLiteral)
     * @returns The requested block without transaction data
     */
    public async getBlockAsync(blockParam: string | BlockParam): Promise<BlockWithoutTransactionData> {
        Web3Wrapper._assertBlockParamOrString(blockParam);
        const encodedBlockParam = marshaller.marshalBlockParam(blockParam);
        const method = utils.isHexStrict(blockParam) ? 'eth_getBlockByHash' : 'eth_getBlockByNumber';
        const shouldIncludeTransactionData = false;
        const blockWithoutTransactionDataWithHexValues = await this._sendRawPayloadAsync<
            BlockWithoutTransactionDataRPC
        >({
            method,
            params: [encodedBlockParam, shouldIncludeTransactionData],
        });
        const blockWithoutTransactionData = marshaller.unmarshalIntoBlockWithoutTransactionData(
            blockWithoutTransactionDataWithHexValues,
        );
        return blockWithoutTransactionData;
    }
    /**
     * Fetch a specific Ethereum block with transaction data
     * @param blockParam The block you wish to fetch (blockHash, blockNumber or blockLiteral)
     * @returns The requested block with transaction data
     */
    public async getBlockWithTransactionDataAsync(blockParam: string | BlockParam): Promise<BlockWithTransactionData> {
        Web3Wrapper._assertBlockParamOrString(blockParam);
        let encodedBlockParam = blockParam;
        if (_.isNumber(blockParam)) {
            encodedBlockParam = utils.numberToHex(blockParam);
        }
        const method = utils.isHexStrict(blockParam) ? 'eth_getBlockByHash' : 'eth_getBlockByNumber';
        const shouldIncludeTransactionData = true;
        const blockWithTransactionDataWithHexValues = await this._sendRawPayloadAsync<BlockWithTransactionDataRPC>({
            method,
            params: [encodedBlockParam, shouldIncludeTransactionData],
        });
        const blockWithoutTransactionData = marshaller.unmarshalIntoBlockWithTransactionData(
            blockWithTransactionDataWithHexValues,
        );
        return blockWithoutTransactionData;
    }
    /**
     * Fetch a block's timestamp
     * @param blockParam The block you wish to fetch (blockHash, blockNumber or blockLiteral)
     * @returns The block's timestamp
     */
    public async getBlockTimestampAsync(blockParam: string | BlockParam): Promise<number> {
        Web3Wrapper._assertBlockParamOrString(blockParam);
        const { timestamp } = await this.getBlockAsync(blockParam);
        return timestamp;
    }
    /**
     * Retrieve the user addresses available through the backing provider
     * @returns Available user addresses
     */
    public async getAvailableAddressesAsync(): Promise<string[]> {
        const addresses = await this._sendRawPayloadAsync<string>({
            method: 'eth_accounts',
            params: [],
        });
        const normalizedAddresses = _.map(addresses, address => address.toLowerCase());
        return normalizedAddresses;
    }
    /**
     * Take a snapshot of the blockchain state on a TestRPC/Ganache local node
     * @returns The snapshot id. This can be used to revert to this snapshot
     */
    public async takeSnapshotAsync(): Promise<number> {
        const snapshotId = Number(await this._sendRawPayloadAsync<string>({ method: 'evm_snapshot', params: [] }));
        return snapshotId;
    }
    /**
     * Revert the blockchain state to a previous snapshot state on TestRPC/Ganache local node
     * @param snapshotId snapshot id to revert to
     * @returns Whether the revert was successful
     */
    public async revertSnapshotAsync(snapshotId: number): Promise<boolean> {
        assert.isNumber('snapshotId', snapshotId);
        const didRevert = await this._sendRawPayloadAsync<boolean>({ method: 'evm_revert', params: [snapshotId] });
        return didRevert;
    }
    /**
     * Mine a block on a TestRPC/Ganache local node
     */
    public async mineBlockAsync(): Promise<void> {
        await this._sendRawPayloadAsync<string>({ method: 'evm_mine', params: [] });
    }
    /**
     * Increase the next blocks timestamp on TestRPC/Ganache or Geth local node.
     * Will throw if provider is neither TestRPC/Ganache or Geth.
     * @param timeDelta Amount of time to add in seconds
     */
    public async increaseTimeAsync(timeDelta: number): Promise<number> {
        assert.isNumber('timeDelta', timeDelta);
        // Detect Geth vs. Ganache and use appropriate endpoint.
        const version = await this.getNodeVersionAsync();
        if (_.includes(version, uniqueVersionIds.geth)) {
            return this._sendRawPayloadAsync<number>({ method: 'debug_increaseTime', params: [timeDelta] });
        } else if (_.includes(version, uniqueVersionIds.ganache)) {
            return this._sendRawPayloadAsync<number>({ method: 'evm_increaseTime', params: [timeDelta] });
        } else {
            throw new Error(`Unknown client version: ${version}`);
        }
    }
    /**
     * Retrieve smart contract logs for a given filter
     * @param filter Parameters by which to filter which logs to retrieve
     * @returns The corresponding log entries
     */
    public async getLogsAsync(filter: FilterObject): Promise<LogEntry[]> {
        let fromBlock = filter.fromBlock;
        if (_.isNumber(fromBlock)) {
            fromBlock = utils.numberToHex(fromBlock);
        }
        let toBlock = filter.toBlock;
        if (_.isNumber(toBlock)) {
            toBlock = utils.numberToHex(toBlock);
        }
        const serializedFilter = {
            ...filter,
            fromBlock,
            toBlock,
        };
        const payload = {
            method: 'eth_getLogs',
            params: [serializedFilter],
        };
        const rawLogs = await this._sendRawPayloadAsync<RawLogEntry[]>(payload);
        const formattedLogs = _.map(rawLogs, marshaller.unmarshalLog.bind(marshaller));
        return formattedLogs;
    }
    /**
     * Calculate the estimated gas cost for a given transaction
     * @param txData Transaction data
     * @returns Estimated gas cost
     */
    public async estimateGasAsync(txData: Partial<TxData>): Promise<number> {
        assert.doesConformToSchema('txData', txData, schemas.txDataSchema, [
            schemas.addressSchema,
            schemas.numberSchema,
            schemas.jsNumber,
        ]);
        const txDataHex = marshaller.marshalTxData(txData);
        const gasHex = await this._sendRawPayloadAsync<string>({ method: 'eth_estimateGas', params: [txDataHex] });
        const gas = utils.convertHexToNumber(gasHex);
        return gas;
    }
    /**
     * Call a smart contract method at a given block height
     * @param callData Call data
     * @param defaultBlock Block height at which to make the call. Defaults to `latest`
     * @returns The raw call result
     */
    public async callAsync(callData: CallData, defaultBlock?: BlockParam): Promise<string> {
        assert.doesConformToSchema('callData', callData, schemas.callDataSchema, [
            schemas.addressSchema,
            schemas.numberSchema,
            schemas.jsNumber,
        ]);
        if (!_.isUndefined(defaultBlock)) {
            Web3Wrapper._assertBlockParam(defaultBlock);
        }
        const marshalledDefaultBlock = marshaller.marshalBlockParam(defaultBlock);
        const callDataHex = marshaller.marshalCallData(callData);
        const rawCallResult = await this._sendRawPayloadAsync<string>({
            method: 'eth_call',
            params: [callDataHex, marshalledDefaultBlock],
        });
        if (rawCallResult === '0x') {
            throw new Error('Contract call failed (returned null)');
        }
        return rawCallResult;
    }
    /**
     * Send a transaction
     * @param txData Transaction data
     * @returns Transaction hash
     */
    public async sendTransactionAsync(txData: TxData): Promise<string> {
        assert.doesConformToSchema('txData', txData, schemas.txDataSchema, [
            schemas.addressSchema,
            schemas.numberSchema,
            schemas.jsNumber,
        ]);
        const txDataHex = marshaller.marshalTxData(txData);
        const txHash = await this._sendRawPayloadAsync<string>({ method: 'eth_sendTransaction', params: [txDataHex] });
        return txHash;
    }
    /**
     * Waits for a transaction to be mined and returns the transaction receipt.
     * Note that just because a transaction was mined does not mean it was
     * successful. You need to check the status code of the transaction receipt
     * to find out if it was successful, or use the helper method
     * awaitTransactionSuccessAsync.
     * @param   txHash            Transaction hash
     * @param   pollingIntervalMs How often (in ms) should we check if the transaction is mined.
     * @param   timeoutMs         How long (in ms) to poll for transaction mined until aborting.
     * @return  Transaction receipt with decoded log args.
     */
    public async awaitTransactionMinedAsync(
        txHash: string,
        pollingIntervalMs: number = 1000,
        timeoutMs?: number,
    ): Promise<TransactionReceiptWithDecodedLogs> {
        assert.isHexString('txHash', txHash);
        assert.isNumber('pollingIntervalMs', pollingIntervalMs);
        if (!_.isUndefined(timeoutMs)) {
            assert.isNumber('timeoutMs', timeoutMs);
        }
        // Immediately check if the transaction has already been mined.
        let transactionReceipt = await this.getTransactionReceiptAsync(txHash);
        if (!_.isNull(transactionReceipt)) {
            const logsWithDecodedArgs = _.map(
                transactionReceipt.logs,
                this.abiDecoder.tryToDecodeLogOrNoop.bind(this.abiDecoder),
            );
            const transactionReceiptWithDecodedLogArgs: TransactionReceiptWithDecodedLogs = {
                ...transactionReceipt,
                logs: logsWithDecodedArgs,
            };
            return transactionReceiptWithDecodedLogArgs;
        }

        // Otherwise, check again every pollingIntervalMs.
        let wasTimeoutExceeded = false;
        if (timeoutMs) {
            setTimeout(() => (wasTimeoutExceeded = true), timeoutMs);
        }

        const txReceiptPromise = new Promise(
            (resolve: (receipt: TransactionReceiptWithDecodedLogs) => void, reject) => {
                const intervalId = intervalUtils.setAsyncExcludingInterval(
                    async () => {
                        if (wasTimeoutExceeded) {
                            intervalUtils.clearAsyncExcludingInterval(intervalId);
                            return reject(Web3WrapperErrors.TransactionMiningTimeout);
                        }

                        transactionReceipt = await this.getTransactionReceiptAsync(txHash);
                        if (!_.isNull(transactionReceipt)) {
                            intervalUtils.clearAsyncExcludingInterval(intervalId);
                            const logsWithDecodedArgs = _.map(
                                transactionReceipt.logs,
                                this.abiDecoder.tryToDecodeLogOrNoop.bind(this.abiDecoder),
                            );
                            const transactionReceiptWithDecodedLogArgs: TransactionReceiptWithDecodedLogs = {
                                ...transactionReceipt,
                                logs: logsWithDecodedArgs,
                            };
                            resolve(transactionReceiptWithDecodedLogArgs);
                        }
                    },
                    pollingIntervalMs,
                    (err: Error) => {
                        intervalUtils.clearAsyncExcludingInterval(intervalId);
                        reject(err);
                    },
                );
            },
        );
        const txReceipt = await txReceiptPromise;
        return txReceipt;
    }
    /**
     * Waits for a transaction to be mined and returns the transaction receipt.
     * Unlike awaitTransactionMinedAsync, it will throw if the receipt has a
     * status that is not equal to 1. A status of 0 or null indicates that the
     * transaction was mined, but failed. See:
     * https://github.com/ethereum/wiki/wiki/JavaScript-API#web3ethgettransactionreceipt
     * @param   txHash            Transaction hash
     * @param   pollingIntervalMs How often (in ms) should we check if the transaction is mined.
     * @param   timeoutMs         How long (in ms) to poll for transaction mined until aborting.
     * @return  Transaction receipt with decoded log args.
     */
    public async awaitTransactionSuccessAsync(
        txHash: string,
        pollingIntervalMs: number = 1000,
        timeoutMs?: number,
    ): Promise<TransactionReceiptWithDecodedLogs> {
        const receipt = await this.awaitTransactionMinedAsync(txHash, pollingIntervalMs, timeoutMs);
        if (receipt.status !== 1) {
            throw new Error(`Transaction failed: ${txHash}`);
        }
        return receipt;
    }
    /**
     * Calls the 'debug_setHead' JSON RPC method, which sets the current head of
     * the local chain by block number. Note, this is a destructive action and
     * may severely damage your chain. Use with extreme caution. As of now, this
     * is only supported by Geth. It sill throw if the 'debug_setHead' method is
     * not supported.
     * @param  blockNumber The block number to reset to.
     */
    public async setHeadAsync(blockNumber: number): Promise<void> {
        assert.isNumber('blockNumber', blockNumber);
        await this._sendRawPayloadAsync<void>({ method: 'debug_setHead', params: [utils.numberToHex(blockNumber)] });
    }
    /**
     * Returns either NodeType.Geth or NodeType.Ganache depending on the type of
     * the backing Ethereum node. Throws for any other type of node.
     */
    public async getNodeTypeAsync(): Promise<NodeType> {
        const version = await this.getNodeVersionAsync();
        if (_.includes(version, uniqueVersionIds.geth)) {
            return NodeType.Geth;
        } else if (_.includes(version, uniqueVersionIds.ganache)) {
            return NodeType.Ganache;
        } else {
            throw new Error(`Unknown client version: ${version}`);
        }
    }
    private async _sendRawPayloadAsync<A>(payload: Partial<JSONRPCRequestPayload>): Promise<A> {
        const sendAsync = this._provider.sendAsync.bind(this._provider);
        const payloadWithDefaults = {
            id: this._jsonRpcRequestId++,
            params: [],
            jsonrpc: '2.0',
            ...payload,
        };
        const response = await promisify<JSONRPCResponsePayload>(sendAsync)(payloadWithDefaults);
        const result = response.result;
        return result;
    }
} // tslint:disable-line:max-file-line-count