Figures out what tokens are missing from the MEW token contract

.env

GET_TOKEN_DEFAULT_PARAM='' // Data object for getAllBAlance for the contract
CONTRACT_ADDRESS='' // Contract address
TOKEN_LIST_SRC='' // Token list source
PRIV='' // account private key
RPC='' // Node you're connecting to
GAS_PRICE = 0
GAS = 0

index.js

require("dotenv").config();
const fs = require("fs");
const Web3 = require("web3");
const fetch = require("node-fetch");
const BigNumber = require("bignumber.js");
const abi = require("./contractABI.js");
const ethUtil = require("ethereumjs-util");
const ethTx = require("ethereumjs-tx");
const privateKey = Buffer.from(process.env.PRIV, 'hex');
let web3 = new Web3();
web3.setProvider(new web3.providers.HttpProvider(process.env.RPC));

function getDataString(func, inputs) {
	return web3.eth.abi.encodeFunctionCall(func, inputs);
}

function sizeHex(bytes) {
	return bytes * 2;
}

function sortAlphabetically(a, b) {
	const first = a.symbol.toUpperCase();
	const second = b.symbol.toUpperCase();
	return first < second ? -1 : first > second ? 1 : 0;
}

function trim(str) {
	return str.replace(/\0[\s\S]*$/g, "");
}

function getAscii(hex) {
	hex = hex.substring(0, 2) === "0x" ? hex : "0x" + hex;
	return trim(web3.utils.hexToAscii(hex));
}

function parseContractToken(hex) {
	let tokens = [];
	hex = hex.substring(0, 2) === "0x" ? hex.substring(2) : hex;
	hex = hex.substring(0, hex.lastIndexOf("1") - 1); //starting point
	let offset = hex.length;
	offset -= sizeHex(32);
	let countTokens = hex.substr(offset, sizeHex(32));
	offset -= sizeHex(1);
	let isName = parseInt(hex.substr(offset, sizeHex(1)));
	offset -= sizeHex(1);
	let isWebSite = parseInt(hex.substr(offset, sizeHex(1)));
	offset -= sizeHex(1);
	let isEmail = parseInt(hex.substr(offset, sizeHex(1)));
	let numTokens = new BigNumber("0x" + countTokens).toNumber();

	for (var i = 0; i < parseInt(numTokens); i++) {
		var token = {};
		offset -= sizeHex(16);
		token.symbol = getAscii(hex.substr(offset, sizeHex(16)));
		offset -= sizeHex(20);
		token.addr = "0x" + hex.substr(offset, sizeHex(20));
		offset -= sizeHex(8);
		token.decimals = new BigNumber(
			"0x" + hex.substr(offset, sizeHex(8))
		).toNumber();
		offset -= sizeHex(32);
		token.balance = new BigNumber(
			"0x" + hex.substr(offset, sizeHex(32))
		).toFixed();
		if (isName) {
			offset -= sizeHex(16);
			token.name = getAscii(hex.substr(offset, sizeHex(16)));
		}
		if (isWebSite) {
			offset -= sizeHex(32);
			token.website = getAscii(hex.substr(offset, sizeHex(32)));
		}
		if (isEmail) {
			offset -= sizeHex(32);
			token.email = getAscii(hex.substr(offset, sizeHex(32)));
		}
		tokens.push(token);
	}
	return tokens;
}

async function getMEWTokens() {
	const response = await fetch(process.env.TOKEN_LIST_SRC);
	const mewTokens = await response.json();
	return mewTokens;
}

async function getContractTokens() {
	const newTokens = await web3.eth
		.call({
			to: process.env.CONTRACT_ADDRESS,
			data: process.env.GET_TOKEN_DEFAULT_PARAM
		})
		.then(function(res) {
			return parseContractToken(res);
		})
		.catch(function(err) {
			throw err;
		});

	return newTokens;
}

var getHex = (str) => {
  return '0x' + Buffer.from(str, 'utf8').toString('hex')
}

async function differenceTokenList(arr) {
	if(arr.length > 0) {
		this.tokensAbi = {};
		for (var i in abi) this.tokensAbi[abi[i].name] = abi[i];
		fs.writeFileSync('./notInContractTokens.json', JSON.stringify(arr));
		const FROM =
		"0x" + ethUtil.privateToAddress("0x"+process.env.PRIV).toString("hex");
		for (let i = 0; i < arr.length; i++) {
			let txCount = await web3.eth.getTransactionCount(FROM);
			let name = getHex(arr[i].name);
			let symbol = getHex(arr[i].symbol);
			let address = arr[i].address;
			let decimal = arr[i].decimals;
			let website = getHex(arr[i].website);
			let email = getHex(arr[i].support.email);
			let dataStr = getDataString(this.tokensAbi.addSetToken, [name, symbol, address, decimal, website, email]);
			const params = {
				nonce: web3.utils.toHex(txCount + i),
				gasPrice: web3.utils.toHex(process.env.GAS_PRICE),
				gasLimit: web3.utils.toHex(process.env.GAS),
				to: web3.utils.toHex(process.env.CONTRACT_ADDRESS),
				value: '0x0',
				data: dataStr,
				chainId: 1
			}
			const tx = new ethTx(params);
			tx.sign(privateKey);
			const serializedTx = tx.serialize();
			const actualTransactionParams = '0x' + serializedTx.toString('hex');
			new Promise(function(resolve, reject) {
				web3.eth.sendSignedTransaction(actualTransactionParams).on('transactionHash',function(hash){
					console.log("Added token " + (arr[i].name, hash);
					resolve();
				}).catch(function(err) {
					console.log(err.message);
					resolve();
				})
			})
		}
	}
}

async function run() {
	const mewTokens = await getMEWTokens();
	const contractTokens = await getContractTokens();
	let diffTokens = [];
	mewTokens.forEach(function(mToken) {
		if (
			!contractTokens.find(function(cToken) {
				return (
					web3.utils.toChecksumAddress(cToken.addr) ===
					web3.utils.toChecksumAddress(mToken.address)
				);
			})
		) {
			diffTokens.push(mToken);
		}
	});
	diffTokens.sort(sortAlphabetically);
	differenceTokenList(diffTokens);
}

run();

package.json

{
  "name": "token-contract",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "node index.js"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "ethereumjs-tx": "^1.3.4",
    "node-fetch": "^2.1.2",
    "utf8": "^3.0.0",
    "web3": "^1.0.0-beta.34"
  },
  "dependencies": {
    "bignumber.js": "^4.0.2",
    "dotenv": "^5.0.1",
    "ethereumjs-util": "^5.1.5"
  }
}