Introduction

Goal

The goal of this tutorial is to guide you through TypeScript's Watch mode. This feature allows for automatic recompilation of your code whenever changes are detected.

What you will learn

By the end of the tutorial, you'll be able to use the Watch mode in TypeScript for faster and more efficient web development.

Prerequisites

Before starting, you should have a basic understanding of TypeScript and have it installed on your machine. If you need help with this, refer to the Official TypeScript Installation Guide.

Step-by-Step Guide

Watch mode in TypeScript is a tool that listens for file changes in your project and automatically recompiles your code. This means you don't have to manually trigger the build command every time you make a change in your TypeScript files.

To use this, all you need to do is add the -w or --watch option to your tsc (TypeScript compiler) command.

tsc --watch

or

tsc -w

The TypeScript compiler will keep running in your terminal, watching for changes in your TypeScript files.

Code Examples

Let's say you have a TypeScript file named index.ts.

// index.ts

let greeting: string = "Hello, TypeScript!";
console.log(greeting);

If you run tsc --watch or tsc -w in your terminal and then make changes to the index.ts file, the compiler will automatically recompile your code.

$ tsc -w

After running this command, you can change the greeting in index.ts:

// index.ts

let greeting: string = "Hello, TypeScript! I'm using the Watch mode.";
console.log(greeting);

The TypeScript compiler will detect the changes and recompile the code. The expected output in the console should be:

$ Hello, TypeScript! I'm using the Watch mode.

Summary

In this tutorial, you've learned how to use the Watch mode in TypeScript for more efficient development. This feature automatically recompiles your code whenever changes are detected, providing faster feedback and fewer interruptions.

For further learning, consider exploring other TypeScript compiler options available, such as --target, --module, --lib, and others.

Practice Exercises

1. Create a simple TypeScript file and print a message to the console. Use the Watch mode to automatically recompile your code when you change the message.
2. Create a TypeScript file with a function that performs a calculation. Use the Watch mode to automatically recompile your code when you change the calculation logic.

Remember, practice is key in learning new skills. So, continue experimenting with TypeScript and its Watch mode to become more proficient in web development.