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Cheela Sathvik
Cheela Sathvik

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Building a High-Performance Zip Puzzle: A Lume-JS Masterclass

#webdev #frontend #javascript #react

If you’ve been on LinkedIn lately, you’ve likely seen the "Zip" puzzle. It’s a beautifully simple grid-based game where you connect numbers in a path. While the game looks simple, implementing it with high-performance reactivity, smooth visual feedback, and infinite background puzzle generation is a great test for any front-end toolset.

Live Demo: sathvikc.github.io/linkedin-zip-puzzle/
Source Code: github.com/sathvikc/linkedin-zip-puzzle
Lume-JS Website: sathvikc.github.io/lume-js/

The Challenge: Beyond Manual DOM Manipulation

In a game like Zip, every move triggers a waterfall of UI changes:

  • The cell you clicked becomes "active."
  • A "path dot" appears.
  • "Connector lines" must draw themselves between the current cell and the previous/next cells.
  • The "Cells Visited" counter increments.
  • Win detection checks if the grid is full.

Doing this manually with document.getElementById is a recipe for spaghetti code.

The Solution: Lume-JS & Ruthless Minimalism

Lume-JS is built on the philosophy of "Ruthless Minimalism." At under 2KB, it provides a Proxy-based reactivity system that is both intuitive and powerful. Unlike VDOM-heavy frameworks, Lume-JS performs surgical DOM updates, which is critical for a game where the UI state changes with every pixel of mouse movement.

1. The Reactive State (An "Antidote" to Spaghetti Code)

Everything in the game starts with a single state() object.

const gameState = state({
    path: [],
    cells: generateInitialGrid(),
    elapsedSeconds: 0
});
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2. Surgical Reactivity vs. Virtual DOM

The magic happens in the rendering. Instead of re-rendering the whole board or diffing a heavy Virtual DOM, we use the repeat addon. Each cell gets its own reactive effect.

render: (cellData, el) => {
    effect(() => {
        const pathIdx = gameState.path.indexOf(cellData.index);
        el.classList.toggle('active', pathIdx !== -1);
    });
}
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This ensures the browser does the absolute minimum work necessary. In a 6x6 grid, when you move your mouse, only a single cell's classes are updated. No reconciliation, no complex diffing—just raw performance.

3. Offloading the Brain: Infinite Puzzles via Web Workers

Generating a valid, solvable Zip puzzle is computationally expensive. To keep the UI at 60fps, I offloaded the "Brain" to a Web Worker using Comlink. This allows for infinite background generation—the game is already preparing your next puzzle while you're still connecting the dots on the current one.

Why Lume-JS? The "Go-Style" Frontend

In an era where front-end bundles are ballooning, Lume-JS proves that you don't need a massive runtime to build premium experiences. It gives you the "DX" (Developer Experience) of a major framework with the performance of vanilla JavaScript.

Whether you're building a viral puzzle game or a complex enterprise dashboard, Lume-JS is a reminder that sometimes, less truly is more.

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