Connect to an existing chromedriver on port 9515

use_existing_chromedriver.js

const {Builder, By, until, Capabilities} = require('selenium-webdriver');

// Make sure `chromedriver --port=9515` was started before
var driver = new Builder()
    .withCapabilities(Capabilities.chrome())
    .usingServer('http://localhost:9515')
    .build();

driver.get('http://www.google.com/ncr')
    .then(_ => driver.findElement(By.name('q')).sendKeys('webdriver'))
    .then(_ => driver.findElement(By.name('btnG')).click())
    .then(_ => driver.wait(until.titleIs('webdriver - Google Search'), 1000))
    .then(_ => driver.quit());