In today's frontend world, it's easy to reach for React, Vue, or Svelte the moment a project needs interactivity, state management, or routing. But the modern browser has evolved dramatically. With native DOM APIs, the History API, Web Components, and powerful language features like Proxies, you can build rich, performant single-page applications (SPAs) using nothing but Vanilla JavaScript.

This approach gives you:

Smaller bundle sizes

Better performance (no virtual DOM overhead)

Full control and understanding of your code

No framework lock-in or version churn

Let's explore how to create a lightweight "Vanilla JS Framework" using five key pillars:

Vanilla JavaScript

The DOM

Routing

Web Components

Reactive Programming with Proxies

We'll build toward a simple todo-style SPA that demonstrates all of them working together.

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