Understanding HMR with Preact and Vite

1. Introduction

In this tutorial, we'll dive into the world of Hot Module Replacement (HMR) with Preact and Vite. HMR is a feature that allows developers to see their changes in real-time without a full page refresh, significantly speeding up the development process.

By the end of this tutorial, you will be able to:
- Understand what Hot Module Replacement (HMR) is
- Know how to set up a Preact project using Vite
- Implement HMR in a Preact and Vite project

Prerequisites

Basic knowledge of JavaScript, HTML, CSS, and familiarity with the terminal/command-line interface is required. Experience with Preact and Vite would be beneficial but is not strictly necessary.

2. Step-by-Step Guide

Hot Module Replacement (HMR)

HMR is a feature that injects updated modules into the active runtime. It allows you to see your changes instantly without refreshing your browser.

Preact

Preact is a fast 3kB alternative to React with the same modern API.

Vite

Vite is a build tool that aims to provide a faster and leaner development experience for modern web projects.

Setting up a Preact project with Vite

To set up a new project with Preact and Vite, you need to have Node.js installed on your machine. Run the following commands in your terminal:

# create a new project using the Vite Preact template
npx create-vite my-app --template preact

# navigate into the new project folder
cd my-app

# install dependencies
npm install

# start the dev server
npm run dev

Implementing HMR

Vite has built-in HMR support. You don't need to configure anything. If you make a change to a .js file while your dev server is running, Vite will update the code in your browser without a full page refresh.

3. Code Examples

Basic Preact Component

Here's an example of a basic Preact component. If you make a change to this component while your dev server is running, Vite's HMR will update your browser instantly.

// src/App.js
import { h } from 'preact';

export function App() {
  return <h1>Hello, world!</h1>;
}

4. Summary

In this tutorial, we explored what HMR is and how it can be used with Preact and Vite to improve the development experience. We also set up a basic Preact project with Vite and saw how Vite's built-in HMR updates the browser instantly when we make changes to our code.

To continue learning about this topic, you could:
- Explore more about Preact
- Read more about Vite
- Learn more about HMR

5. Practice Exercises

1. Set up a new Preact project with Vite and create a basic component.
2. Add a state to your component and create a button that changes this state when clicked.
3. Add a CSS file and change the styles of your component. Observe how the styles update in your browser instantly thanks to Vite's HMR.

Solutions to these exercises are left for the reader as they depend on personal preference. Remember, the key to becoming a better programmer is practice!