Create HookedWalletEthTx Subprovider for web3 to make it work on web

Web3HookedWalletEthTxSubprovider.js

import Web3 from 'web3';

const ProviderEngine = require('web3-provider-engine');

const Web3Subprovider = require('web3-provider-engine/subproviders/web3.js');

const HookedWalletEthTxSubprovider = require('web3-provider-engine/subproviders/hooked-wallet-ethtx.js');

const PUBLIC_ACCOUNT = '0xPUBLIC_ACCOUNT_HERE';

const network = truffleConfig.networks.ropsten;
const TESTRPC_ADDRESS = `${network.protocol}://${network.host}/${network.key}`;

function WalletProvider(provider_url) {
	this.engine = new ProviderEngine();
	// https://github.com/MetaMask/provider-engine
	this.engine.addProvider(
		new HookedWalletEthTxSubprovider({
			getAccounts: function(callback) {
				callback(null, [PUBLIC_ACCOUNT]);
			},
			getPrivateKey: function(address, callback) {
				if (address === PUBLIC_ACCOUNT) {
					const privateBuffered = Buffer.from(
						'PRIVATE_KEY_HERE',
						'hex'
					);
					return callback(null, privateBuffered);
				}
				return callback(new Error('not private key supplied for that account'));
			},
		})
	);
	this.engine.addProvider(
		new Web3Subprovider(new Web3.providers.HttpProvider(provider_url))
	);
	this.engine.start(); // Required by the provider engine.
}

WalletProvider.prototype.sendAsync = function() {
	this.engine.sendAsync.apply(this.engine, arguments);
};

WalletProvider.prototype.send = function() {
	return this.engine.send.apply(this.engine, arguments);
};

WalletProvider.prototype.getAddress = function() {
	return this.address;
};

const web3Provider = new WalletProvider(TESTRPC_ADDRESS);

const web3 = new Web3(web3Provider);