Node.js out of the box has virtually full support for ES6 (also known as ES2015) in version 6 and later versions. That means that even the long-term supported versions of Node.js now fully support ES6 syntax and features. However, many of the advanced language features used in Angular, such as optional typing, decorators, and interfaces are only available by using TypeScript. Using the same flavor of JavaScript helps you reduce the cost of context shifting between the backend and frontend of our web application. TypeScript will also help us prevent common typing errors and better modularization of our code. Luckily, TypeScript had first-class support for Node.js since the beginning. Let's explore how to convert our Express web server to use TypeScript.