index.js

const fs = require('fs');
const Web3 = require('web3');
const web3 = new Web3('https://mainnet.infura.io/v3/1198c5abaa8c4d3e8e170694ca1e3d59');

const abi = [{
    "constant": true,
    "inputs": [{"name": "", "type": "address"}],
    "name": "registers",
    "outputs": [{"name": "", "type": "string"}],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
}];

const linkerAddress = '0x8b748672f7ff9c46647106c7c735e33bfbaca47b';

(async () => {
    const addresses = fs.readFileSync('export-0x8b748672f7ff9c46647106c7c735e33bfbaca47b.csv', {encoding: 'UTF-8'})
        .split('\n')
        .filter((_, index) => index !== 0 && index !== 1)
        .map(e => e.split(",")[4])
        .map(e => e.match(/\w+/)[0])
        .map(e => e.toLowerCase())
        .filter((value, index, self) => self.indexOf(value) === index);

    const linker = new web3.eth.Contract(abi, linkerAddress);

    const ethBnbLinks = [];

    fs.writeFileSync('addresses.csv', '');
    for (const ethAddress of addresses) {
        const bnbAddress = await linker.methods.registers(ethAddress).call();
        if (bnbAddress !== '') {
            ethBnbLinks.push({ ethAddress, bnbAddress });
        }
    }

    ethBnbLinks.forEach(({ ethAddress, bnbAddress }) => fs.appendFileSync('addresses.csv', `${ethAddress},${bnbAddress}\n`))
})();

package.json

{
  "name": "linkFetcher",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "dependencies": {
    "web3": "^1.0.0-beta.55"
  }
}