WebAssembly (often abbreviated as **Wasm**) is a **binary instruction format** designed as a portable compilation target for high-level languages like C, C++, Rust, and even TypeScript. Unlike JavaScript, which is interpreted or Just-In-Time (JIT) compiled, WebAssembly is **pre-compiled**, allowing it to run at near-native speed in the browser. ### <br>**How Does WebAssembly Improve Performance?** WebAssembly boosts performance in several key ways: 1. **Faster Execution** – Since Wasm is a low-level binary format, browsers can decode and execute it much faster than parsing JavaScript. This is especially useful for **compute-heavy tasks** like games, video editing, or scientific simulations. 2. **Smaller File Size** – Wasm binaries are compact, reducing download times compared to equivalent JavaScript. 3. **Predictable Performance** – Unlike JavaScript, which relies on optimizations during JIT compilation, Wasm is optimized **ahead of time**, leading to more consistent execution speeds. 4. **Multi-language Support** – Developers can write performance-critical code in languages like **Rust or C++** and compile it to Wasm, while keeping the rest of the app in JavaScript. ### <br>**Example: Fibonacci in WebAssembly vs JavaScript** Let’s compare a simple **Fibonacci sequence** calculation in both Wasm (written in C) and JavaScript. #### <br>**C Code (Compiled to WebAssembly)** ```c int fib(int n) { if (n <= 1) return n; return fib(n - 1) + fib(n - 2); } ``` After compiling this to Wasm (e.g., using **Emscripten**), it runs **much faster** than the JS equivalent for large `n`. #### <br>**JavaScript Equivalent** ```javascript function fib(n) { if (n <= 1) return n; return fib(n - 1) + fib(n - 2); } ``` While this works, JavaScript’s recursive calls are slower due to its dynamic nature. ### <br>**Real-World Use Cases** - **Games (Unity, Unreal Engine)** – WebAssembly allows AAA game engines to run smoothly in browsers. - **Image/Video Processing** – Apps like **Figma** and **Photoshop** use Wasm for real-time rendering. - **Blockchain (Ethereum, Polkadot)** – Smart contracts benefit from Wasm’s speed and security. ### <br>**Conclusion** WebAssembly doesn’t replace JavaScript but **complements it** by handling performance-critical tasks. By enabling near-native execution in the browser, it opens doors to **faster, richer web applications** without plugins or slow interpreted code.