install_extension_in_chrome.js

import webdriver from 'selenium-webdriver';
import { Driver, Options } from 'selenium-webdriver/chrome';

const EXT_PATH = //YOUR_LOCAL_EXTENSION_PATH

const chromeOptions = { args: [`load-extension=${EXT_PATH}`] };

const driver = new webdriver.Builder()
    .withCapabilities({ chromeOptions })
    .build();

// You can start work with driver now.