Refactor Web3Wrapper to no longer use Web3.js & add more test coverage

5 files changed, 345 insertions, 62 deletions

diff --git a/packages/web3-wrapper/src/globals.d.ts b/packages/web3-wrapper/src/globals.d.ts
index 94e63a32d..09c9fd819 100644
--- a/packages/web3-wrapper/src/globals.d.ts
+++ b/packages/web3-wrapper/src/globals.d.ts
@@ -1,3 +1,11 @@
+declare module 'web3-utils' {
+    import * as BigNumber from 'bignumber.js';
+
+    const toHex: (val: any) => string;
+    const isHexStrict: (val: any) => boolean;
+    const toDecimal: (val: any) => number;
+}
+
 declare module '*.json' {
     const json: any;
     /* tslint:disable */
diff --git a/packages/web3-wrapper/src/marshaller.ts b/packages/web3-wrapper/src/marshaller.ts
new file mode 100644
index 000000000..06556ce90
--- /dev/null
+++ b/packages/web3-wrapper/src/marshaller.ts
@@ -0,0 +1,177 @@
+import { addressUtils, BigNumber } from '@0xproject/utils';
+import {
+    BlockParam,
+    BlockParamLiteral,
+    BlockWithoutTransactionData,
+    BlockWithTransactionData,
+    CallData,
+    CallTxDataBase,
+    LogEntry,
+    RawLogEntry,
+    Transaction,
+    TxData,
+} from 'ethereum-types';
+import ethUtil = require('ethereumjs-util');
+import * as _ from 'lodash';
+import web3Utils = require('web3-utils');
+
+import { utils } from './utils';
+
+import {
+    AbstractBlockRPC,
+    BlockWithoutTransactionDataRPC,
+    BlockWithTransactionDataRPC,
+    CallDataRPC,
+    CallTxDataBaseRPC,
+    TransactionRPC,
+    TxDataRPC,
+} from './types';
+
+export const marshaller = {
+    unmarshalIntoBlockWithoutTransactionData(
+        blockWithHexValues: BlockWithoutTransactionDataRPC,
+    ): BlockWithoutTransactionData {
+        const block = {
+            ...blockWithHexValues,
+            gasLimit: web3Utils.toDecimal(blockWithHexValues.gasLimit),
+            gasUsed: web3Utils.toDecimal(blockWithHexValues.gasUsed),
+            size: web3Utils.toDecimal(blockWithHexValues.size),
+            timestamp: web3Utils.toDecimal(blockWithHexValues.timestamp),
+            number: _.isNull(blockWithHexValues.number) ? null : web3Utils.toDecimal(blockWithHexValues.number),
+            difficulty: this._convertAmountToBigNumber(blockWithHexValues.difficulty),
+            totalDifficulty: this._convertAmountToBigNumber(blockWithHexValues.totalDifficulty),
+        };
+        return block;
+    },
+    unmarshalIntoBlockWithTransactionData(blockWithHexValues: BlockWithTransactionDataRPC): BlockWithTransactionData {
+        const block = {
+            ...blockWithHexValues,
+            gasLimit: web3Utils.toDecimal(blockWithHexValues.gasLimit),
+            gasUsed: web3Utils.toDecimal(blockWithHexValues.gasUsed),
+            size: web3Utils.toDecimal(blockWithHexValues.size),
+            timestamp: web3Utils.toDecimal(blockWithHexValues.timestamp),
+            number: _.isNull(blockWithHexValues.number) ? null : web3Utils.toDecimal(blockWithHexValues.number),
+            difficulty: this._convertAmountToBigNumber(blockWithHexValues.difficulty),
+            totalDifficulty: this._convertAmountToBigNumber(blockWithHexValues.totalDifficulty),
+            transactions: [] as Transaction[],
+        };
+        block.transactions = _.map(blockWithHexValues.transactions, (tx: TransactionRPC) => {
+            const transaction = this.unmarshalTransaction(tx);
+            return transaction;
+        });
+        return block;
+    },
+    unmarshalTransaction(txRpc: TransactionRPC): Transaction {
+        const tx = {
+            ...txRpc,
+            blockNumber: !_.isNull(txRpc.blockNumber) ? web3Utils.toDecimal(txRpc.blockNumber) : null,
+            transactionIndex: !_.isNull(txRpc.transactionIndex) ? web3Utils.toDecimal(txRpc.transactionIndex) : null,
+            nonce: web3Utils.toDecimal(txRpc.nonce),
+            gas: web3Utils.toDecimal(txRpc.gas),
+            gasPrice: this._convertAmountToBigNumber(txRpc.gasPrice),
+            value: this._convertAmountToBigNumber(txRpc.value),
+        };
+        return tx;
+    },
+    marshalTxData(txData: Partial<TxData>): Partial<TxDataRPC> {
+        if (_.isUndefined(txData.from)) {
+            throw new Error(`txData is missing required "from" address.`);
+        }
+        const callTxDataBase = {
+            ...txData,
+        };
+        delete callTxDataBase.from;
+        const callTxDataBaseRPC = this._marshalCallTxDataBase(callTxDataBase);
+        const txDataRPC = {
+            ...callTxDataBaseRPC,
+            from: this.marshalAddress(txData.from),
+        };
+        const prunableIfUndefined = ['gasPrice', 'gas', 'value', 'nonce'];
+        _.each(txDataRPC, (value: any, key: string) => {
+            if (_.isUndefined(value) && _.includes(prunableIfUndefined, key)) {
+                delete (txDataRPC as any)[key];
+            }
+        });
+        return txDataRPC;
+    },
+    marshalCallData(callData: Partial<CallData>): Partial<CallDataRPC> {
+        const callTxDataBase = {
+            ...callData,
+        };
+        delete callTxDataBase.from;
+        const callTxDataBaseRPC = this._marshalCallTxDataBase(callTxDataBase);
+        const callDataRPC = {
+            ...callTxDataBaseRPC,
+            from: _.isUndefined(callData.from) ? undefined : this.marshalAddress(callData.from),
+        };
+        return callDataRPC;
+    },
+    marshalAddress(address: string): string {
+        if (addressUtils.isAddress(address)) {
+            return ethUtil.addHexPrefix(address);
+        }
+        throw new Error(`Invalid address encountered: ${address}`);
+    },
+    marshalBlockParam(blockParam: BlockParam | string | number | undefined): string | undefined {
+        if (_.isUndefined(blockParam)) {
+            return BlockParamLiteral.Latest;
+        }
+        const encodedBlockParam = _.isNumber(blockParam) ? web3Utils.toHex(blockParam) : blockParam;
+        return encodedBlockParam;
+    },
+    unmarshalLog(rawLog: RawLogEntry): LogEntry {
+        const formattedLog = {
+            ...rawLog,
+            logIndex: this.convertHexToNumberOrNull(rawLog.logIndex),
+            blockNumber: this.convertHexToNumberOrNull(rawLog.blockNumber),
+            transactionIndex: this.convertHexToNumberOrNull(rawLog.transactionIndex),
+        };
+        return formattedLog;
+    },
+    _marshalCallTxDataBase(callTxDataBase: Partial<CallTxDataBase>): Partial<CallTxDataBaseRPC> {
+        const callTxDataBaseRPC = {
+            ...callTxDataBase,
+            to: _.isUndefined(callTxDataBase.to) ? undefined : this.marshalAddress(callTxDataBase.to),
+            gasPrice: _.isUndefined(callTxDataBase.gasPrice)
+                ? undefined
+                : this._encodeAmountAsHexString(callTxDataBase.gasPrice),
+            gas: _.isUndefined(callTxDataBase.gas) ? undefined : this._encodeAmountAsHexString(callTxDataBase.gas),
+            value: _.isUndefined(callTxDataBase.value)
+                ? undefined
+                : this._encodeAmountAsHexString(callTxDataBase.value),
+            nonce: _.isUndefined(callTxDataBase.nonce)
+                ? undefined
+                : this._encodeAmountAsHexString(callTxDataBase.nonce),
+        };
+
+        return callTxDataBaseRPC;
+    },
+    convertHexToNumberOrNull(hex: string | null): number | null {
+        if (_.isNull(hex)) {
+            return null;
+        }
+        const decimal = web3Utils.toDecimal(hex);
+        return decimal;
+    },
+    _convertAmountToBigNumber(value: string | number | BigNumber): BigNumber {
+        const num = value || 0;
+        const isBigNumber = utils.isBigNumber(num);
+        if (isBigNumber) {
+            return num as BigNumber;
+        }
+
+        if (_.isString(num) && (num.indexOf('0x') === 0 || num.indexOf('-0x') === 0)) {
+            return new BigNumber(num.replace('0x', ''), 16);
+        }
+
+        const baseTen = 10;
+        return new BigNumber((num as number).toString(baseTen), baseTen);
+    },
+    _encodeAmountAsHexString(value: string | number | BigNumber): string {
+        const valueBigNumber = this._convertAmountToBigNumber(value);
+        const hexBase = 16;
+        const valueHex = valueBigNumber.toString(hexBase);
+
+        return valueBigNumber.lessThan(0) ? '-0x' + valueHex.substr(1) : '0x' + valueHex;
+    },
+};
diff --git a/packages/web3-wrapper/src/types.ts b/packages/web3-wrapper/src/types.ts
index 79542da10..54a5f3f0e 100644
--- a/packages/web3-wrapper/src/types.ts
+++ b/packages/web3-wrapper/src/types.ts
@@ -1,3 +1,59 @@
 export enum Web3WrapperErrors {
     TransactionMiningTimeout = 'TRANSACTION_MINING_TIMEOUT',
 }
+
+export interface AbstractBlockRPC {
+    number: string | null;
+    hash: string | null;
+    parentHash: string;
+    nonce: string | null;
+    sha3Uncles: string;
+    logsBloom: string | null;
+    transactionsRoot: string;
+    stateRoot: string;
+    miner: string;
+    difficulty: string;
+    totalDifficulty: string;
+    extraData: string;
+    size: string;
+    gasLimit: string;
+    gasUsed: string;
+    timestamp: string;
+    uncles: string[];
+}
+export interface BlockWithoutTransactionDataRPC extends AbstractBlockRPC {
+    transactions: string[];
+}
+export interface BlockWithTransactionDataRPC extends AbstractBlockRPC {
+    transactions: TransactionRPC[];
+}
+export interface TransactionRPC {
+    hash: string;
+    nonce: number;
+    blockHash: string | null;
+    blockNumber: string | null;
+    transactionIndex: string | null;
+    from: string;
+    to: string | null;
+    value: string;
+    gasPrice: string;
+    gas: string;
+    input: string;
+}
+
+export interface CallTxDataBaseRPC {
+    to?: string;
+    value?: string;
+    gas?: string;
+    gasPrice?: string;
+    data?: string;
+    nonce?: string;
+}
+
+export interface TxDataRPC extends CallTxDataBaseRPC {
+    from: string;
+}
+
+export interface CallDataRPC extends CallTxDataBaseRPC {
+    from?: string;
+}
diff --git a/packages/web3-wrapper/src/utils.ts b/packages/web3-wrapper/src/utils.ts
new file mode 100644
index 000000000..376f7e89b
--- /dev/null
+++ b/packages/web3-wrapper/src/utils.ts
@@ -0,0 +1,8 @@
+import * as _ from 'lodash';
+
+export const utils = {
+    isBigNumber(value: any): boolean {
+        const isBigNumber = _.isObject(value) && (value as any).isBigNumber;
+        return isBigNumber;
+    },
+};
diff --git a/packages/web3-wrapper/src/web3_wrapper.ts b/packages/web3-wrapper/src/web3_wrapper.ts
index 640d3eac9..29adb18ff 100644
--- a/packages/web3-wrapper/src/web3_wrapper.ts
+++ b/packages/web3-wrapper/src/web3_wrapper.ts
@@ -20,9 +20,15 @@ import {
     TxData,
 } from 'ethereum-types';
 import * as _ from 'lodash';
-import * as Web3 from 'web3';
+import * as web3Utils from 'web3-utils';
 
-import { Web3WrapperErrors } from './types';
+import { marshaller } from './marshaller';
+import {
+    BlockWithoutTransactionDataRPC,
+    BlockWithTransactionDataRPC,
+    TransactionRPC,
+    Web3WrapperErrors,
+} from './types';
 
 const BASE_TEN = 10;
 
@@ -34,7 +40,7 @@ export const uniqueVersionIds = {
 };
 
 /**
- * A wrapper around the Web3.js 0.x library that provides a consistent, clean promise-based interface.
+ * An alternative to the Web3.js library that provides a consistent, clean, promise-based interface.
  */
 export class Web3Wrapper {
     /**
@@ -42,7 +48,7 @@ export class Web3Wrapper {
      */
     public isZeroExWeb3Wrapper = true;
     public abiDecoder: AbiDecoder;
-    private _web3: Web3;
+    private _provider: Provider;
     private _txDefaults: Partial<TxData>;
     private _jsonRpcRequestId: number;
     /**
@@ -117,6 +123,20 @@ export class Web3Wrapper {
             }
         }
     }
+    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 web3Utils.toDecimal(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
@@ -133,8 +153,7 @@ export class Web3Wrapper {
             (provider as any).sendAsync = (provider as any).send;
         }
         this.abiDecoder = new AbiDecoder([]);
-        this._web3 = new Web3();
-        this._web3.setProvider(provider);
+        this._provider = provider;
         this._txDefaults = txDefaults || {};
         this._jsonRpcRequestId = 0;
     }
@@ -150,7 +169,7 @@ export class Web3Wrapper {
      * @return  Web3 provider instance
      */
     public getProvider(): Provider {
-        return this._web3.currentProvider;
+        return this._provider;
     }
     /**
      * Update the used Web3 provider
@@ -158,7 +177,7 @@ export class Web3Wrapper {
      */
     public setProvider(provider: Provider): void {
         assert.isWeb3Provider('provider', provider);
-        this._web3.setProvider(provider);
+        this._provider = provider;
     }
     /**
      * Check whether an address is available through the backing provider. This can be
@@ -196,9 +215,13 @@ export class Web3Wrapper {
      * @returns The transaction receipt, including it's status (0: failed, 1: succeeded or undefined: not found)
      */
     public async getTransactionReceiptAsync(txHash: string): Promise<TransactionReceipt> {
-        const transactionReceipt = await promisify<TransactionReceipt>(this._web3.eth.getTransactionReceipt)(txHash);
+        assert.isHexString('txHash', txHash);
+        const transactionReceipt = await this._sendRawPayloadAsync<TransactionReceipt>({
+            method: 'eth_getTransactionReceipt',
+            params: [txHash],
+        });
         if (!_.isNull(transactionReceipt)) {
-            transactionReceipt.status = this._normalizeTxReceiptStatus(transactionReceipt.status);
+            transactionReceipt.status = Web3Wrapper._normalizeTxReceiptStatus(transactionReceipt.status);
         }
         return transactionReceipt;
     }
@@ -233,9 +256,17 @@ export class Web3Wrapper {
      * @param  address Address of the contract
      * @return Code of the contract
      */
-    public async getContractCodeAsync(address: string): Promise<string> {
+    public async getContractCodeAsync(address: string, defaultBlock?: BlockParam): Promise<string> {
         assert.isETHAddressHex('address', address);
-        const code = await promisify<string>(this._web3.eth.getCode)(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;
     }
     /**
@@ -260,8 +291,12 @@ export class Web3Wrapper {
      */
     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 promisify<string>(this._web3.eth.sign)(address, message);
+        const signData = await this._sendRawPayloadAsync<string>({
+            method: 'eth_sign',
+            params: [address, message],
+        });
         return signData;
     }
     /**
@@ -269,8 +304,12 @@ export class Web3Wrapper {
      * @returns Block number
      */
     public async getBlockNumberAsync(): Promise<number> {
-        const blockNumber = await promisify<number>(this._web3.eth.getBlockNumber)();
-        return blockNumber;
+        const blockNumberHex = await this._sendRawPayloadAsync<string>({
+            method: 'eth_blockNumber',
+            params: [],
+        });
+        const blockNumber = marshaller.convertHexToNumberOrNull(blockNumberHex);
+        return blockNumber as number;
     }
     /**
      * Fetch a specific Ethereum block without transaction data
@@ -279,10 +318,17 @@ export class Web3Wrapper {
      */
     public async getBlockAsync(blockParam: string | BlockParam): Promise<BlockWithoutTransactionData> {
         Web3Wrapper._assertBlockParamOrString(blockParam);
+        const encodedBlockParam = marshaller.marshalBlockParam(blockParam);
+        const method = web3Utils.isHexStrict(blockParam) ? 'eth_getBlockByHash' : 'eth_getBlockByNumber';
         const shouldIncludeTransactionData = false;
-        const blockWithoutTransactionData = await promisify<BlockWithoutTransactionData>(this._web3.eth.getBlock)(
-            blockParam,
-            shouldIncludeTransactionData,
+        const blockWithoutTransactionDataWithHexValues = await this._sendRawPayloadAsync<
+            BlockWithoutTransactionDataRPC
+        >({
+            method,
+            params: [encodedBlockParam, shouldIncludeTransactionData],
+        });
+        const blockWithoutTransactionData = marshaller.unmarshalIntoBlockWithoutTransactionData(
+            blockWithoutTransactionDataWithHexValues,
         );
         return blockWithoutTransactionData;
     }
@@ -293,12 +339,20 @@ export class Web3Wrapper {
      */
     public async getBlockWithTransactionDataAsync(blockParam: string | BlockParam): Promise<BlockWithTransactionData> {
         Web3Wrapper._assertBlockParamOrString(blockParam);
+        let encodedBlockParam = blockParam;
+        if (_.isNumber(blockParam)) {
+            encodedBlockParam = web3Utils.toHex(blockParam);
+        }
+        const method = web3Utils.isHexStrict(blockParam) ? 'eth_getBlockByHash' : 'eth_getBlockByNumber';
         const shouldIncludeTransactionData = true;
-        const blockWithTransactionData = await promisify<BlockWithTransactionData>(this._web3.eth.getBlock)(
-            blockParam,
-            shouldIncludeTransactionData,
+        const blockWithTransactionDataWithHexValues = await this._sendRawPayloadAsync<BlockWithTransactionDataRPC>({
+            method,
+            params: [encodedBlockParam, shouldIncludeTransactionData],
+        });
+        const blockWithoutTransactionData = marshaller.unmarshalIntoBlockWithTransactionData(
+            blockWithTransactionDataWithHexValues,
         );
-        return blockWithTransactionData;
+        return blockWithoutTransactionData;
     }
     /**
      * Fetch a block's timestamp
@@ -315,7 +369,10 @@ export class Web3Wrapper {
      * @returns Available user addresses
      */
     public async getAvailableAddressesAsync(): Promise<string[]> {
-        const addresses = await promisify<string[]>(this._web3.eth.getAccounts)();
+        const addresses = await this._sendRawPayloadAsync<string>({
+            method: 'eth_accounts',
+            params: [],
+        });
         const normalizedAddresses = _.map(addresses, address => address.toLowerCase());
         return normalizedAddresses;
     }
@@ -368,11 +425,11 @@ export class Web3Wrapper {
     public async getLogsAsync(filter: FilterObject): Promise<LogEntry[]> {
         let fromBlock = filter.fromBlock;
         if (_.isNumber(fromBlock)) {
-            fromBlock = this._web3.toHex(fromBlock);
+            fromBlock = web3Utils.toHex(fromBlock);
         }
         let toBlock = filter.toBlock;
         if (_.isNumber(toBlock)) {
-            toBlock = this._web3.toHex(toBlock);
+            toBlock = web3Utils.toHex(toBlock);
         }
         const serializedFilter = {
             ...filter,
@@ -380,12 +437,11 @@ export class Web3Wrapper {
             toBlock,
         };
         const payload = {
-            jsonrpc: '2.0',
             method: 'eth_getLogs',
             params: [serializedFilter],
         };
         const rawLogs = await this._sendRawPayloadAsync<RawLogEntry[]>(payload);
-        const formattedLogs = _.map(rawLogs, this._formatLog.bind(this));
+        const formattedLogs = _.map(rawLogs, marshaller.unmarshalLog.bind(marshaller));
         return formattedLogs;
     }
     /**
@@ -394,7 +450,9 @@ export class Web3Wrapper {
      * @returns Estimated gas cost
      */
     public async estimateGasAsync(txData: Partial<TxData>): Promise<number> {
-        const gas = await promisify<number>(this._web3.eth.estimateGas)(txData);
+        const txDataHex = marshaller.marshalTxData(txData);
+        const gasHex = await this._sendRawPayloadAsync<string>({ method: 'eth_estimateGas', params: [txDataHex] });
+        const gas = web3Utils.toDecimal(gasHex);
         return gas;
     }
     /**
@@ -407,7 +465,12 @@ export class Web3Wrapper {
         if (!_.isUndefined(defaultBlock)) {
             Web3Wrapper._assertBlockParam(defaultBlock);
         }
-        const rawCallResult = await promisify<string>(this._web3.eth.call)(callData, 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)');
         }
@@ -419,7 +482,8 @@ export class Web3Wrapper {
      * @returns Transaction hash
      */
     public async sendTransactionAsync(txData: TxData): Promise<string> {
-        const txHash = await promisify<string>(this._web3.eth.sendTransaction)(txData);
+        const txDataHex = marshaller.marshalTxData(txData);
+        const txHash = await this._sendRawPayloadAsync<string>({ method: 'eth_sendTransaction', params: [txDataHex] });
         return txHash;
     }
     /**
@@ -529,10 +593,10 @@ export class Web3Wrapper {
      */
     public async setHeadAsync(blockNumber: number): Promise<void> {
         assert.isNumber('blockNumber', blockNumber);
-        await this._sendRawPayloadAsync<void>({ method: 'debug_setHead', params: [this._web3.toHex(blockNumber)] });
+        await this._sendRawPayloadAsync<void>({ method: 'debug_setHead', params: [web3Utils.toHex(blockNumber)] });
     }
     private async _sendRawPayloadAsync<A>(payload: Partial<JSONRPCRequestPayload>): Promise<A> {
-        const sendAsync = this._web3.currentProvider.sendAsync.bind(this._web3.currentProvider);
+        const sendAsync = this._provider.sendAsync.bind(this._provider);
         const payloadWithDefaults = {
             id: this._jsonRpcRequestId++,
             params: [],
@@ -543,34 +607,4 @@ export class Web3Wrapper {
         const result = response.result;
         return result;
     }
-    private _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 this._web3.toDecimal(status) as 0 | 1;
-        } else if (_.isUndefined(status)) {
-            return null;
-        } else {
-            return status;
-        }
-    }
-    private _formatLog(rawLog: RawLogEntry): LogEntry {
-        const formattedLog = {
-            ...rawLog,
-            logIndex: this._hexToDecimal(rawLog.logIndex),
-            blockNumber: this._hexToDecimal(rawLog.blockNumber),
-            transactionIndex: this._hexToDecimal(rawLog.transactionIndex),
-        };
-        return formattedLog;
-    }
-    private _hexToDecimal(hex: string | null): number | null {
-        if (_.isNull(hex)) {
-            return null;
-        }
-        const decimal = this._web3.toDecimal(hex);
-        return decimal;
-    }
 } // tslint:disable-line:max-file-line-count