What is Preact?

Purpose

Explain what Preact is and when it is used.

Audience

This document is intended for junior developers who are unfamiliar with Preact and have basic knowledge of React.

Definition

Preact is a lightweight JavaScript library that serves as an alternative to React. It provides a largely compatible API with a significantly smaller bundle size and focuses on performance and efficiency by minimizing overhead and optimizing rendering.

How Preact Works (High-Level)

Preact uses a virtual DOM, similar to React, but implements it in a more compact way, which contributes to faster load times and reduced memory usage.

Why Preact is Used

Because of its compatibility with React, many existing React applications can use Preact with minimal changes, often through tooling or aliases. Preact is commonly used in environments where JavaScript size and performance are critical, such as mobile web applications, low-powered devices, or embedded systems.

Key Takeaways

• Preact is a lightweight JavaScript alternative to React
• It uses a compact virtual DOM implementation to improve performance
• Many React applications can adopt Preact with minimal changes
• Preact is well-suited for performance- and size-constrained environments