Episode 2 of 21

Compiling TypeScript

Learn how to compile TypeScript files into JavaScript and set up a watch mode.

Browsers and Node.js don't understand TypeScript directly. You need to compile it to JavaScript first.

tsc sandbox.ts

This creates a sandbox.js file with plain JavaScript. Include that JS file in your HTML:

<script src="sandbox.js"></script>

Recompiling manually every time is tedious. Use watch mode to auto-compile on save:

tsc sandbox.ts -w

Now every time you save sandbox.ts, it automatically recompiles to sandbox.js.

TypeScript strips all type annotations and compiles modern JS syntax down to compatible JavaScript:

// TypeScript
const greet = (name: string): string => {
    return `Hello ${name}`;
};

// Compiled JavaScript
"use strict";
const greet = (name) => {
    return `Hello ${name}`;
};