Executing JavaScript in Selenium in Node.js :
https://www.softpost.org/selenium-with-node-js/executing-javascript-in-selenium-in-node-js/
JavaScriptExecutor in Selenium WebDriver With Examples:
https://www.softwaretestingmaterial.com/javascriptexecutor-selenium-webdriver/
ES6 Promises :
https://www.datchley.name/es6-promises/
