WebAssembly (WASM) for High Performance Apps · 강의

WASM 스레드를 활용한 Web Workers

Web Workers를 통합하여 별도의 스레드에서 WASM 모듈을 실행하고 UI 차단을 방지하여 응답성을 향상합니다.

WASM 스레드를 활용한 Web Workers은(는) CoddyKit의 무료 WebAssembly (WASM) for High Performance Apps 강의입니다. 이것은 4개 중 1번째 강의입니다. 아래에서 전체 강의를 무료로 읽을 수 있으며, 내장 코드 에디터와 24/7 AI 튜터와 함께 브라우저에서 직접 실습할 수 있습니다. 이 강의는 WebAssembly (WASM) for High Performance Apps 학습 경로의 일부이며, 진행 상황이 웹과 CoddyKit 앱에 동기화됩니다. WebAssembly (WASM) for High Performance Apps 강의에는 총 4개의 강의가 포함되어 있습니다.

이 강의의 일부는 아직 번역되지 않았으며 영어로 표시됩니다.

Preventing UI Freezes

Web applications often need to perform complex tasks, like heavy calculations or data processing. If these tasks run directly on the main browser thread, they can cause the user interface (UI) to freeze and become unresponsive.

This leads to a poor user experience. To avoid this, we need ways to run code concurrently, or in parallel, without blocking the UI.

Meet Web Workers

Web Workers are a JavaScript feature that allows scripts to run in the background, separate from the main execution thread of a web page.

They have their own global scope.
They cannot directly access the Document Object Model (DOM).
They communicate with the main thread using messages.

This isolation is key to keeping your UI responsive.

WASM on the Main Thread

By default, when you load and execute a WebAssembly (WASM) module in a web page, it runs on the main JavaScript thread, just like regular JavaScript code.

If your WASM module performs a very long or computationally intensive operation, it will block the main thread. This means the browser won't be able to update the UI, respond to user input, or run other scripts until the WASM task is complete.

WASM + Workers = Power

Combining Web Workers with WebAssembly offers a powerful solution for high-performance web applications. You can:

Run CPU-intensive WASM computations (like image processing, video encoding, or complex simulations) in a separate thread.
Keep the main thread free and responsive for UI updates and user interactions.
Leverage the near-native speed of WASM without sacrificing user experience.

Spawning a Web Worker

You create a Web Worker by instantiating the Worker object with the URL of a script file. This script will then run in its own thread.

The main script can then send messages to this worker, and the worker can send messages back.

const workerCode = `
  self.onmessage = (e) => {
    console.log('Worker received:', e.data);
    self.postMessage('Worker says hello!');
  };
`;
const blob = new Blob([workerCode], { type: 'application/javascript' });
const worker = new Worker(URL.createObjectURL(blob));

worker.onmessage = (event) => {
  console.log('Main received:', event.data);
};

worker.postMessage('Hello from main!');
console.log('Main thread finished setup.');

Loading WASM in a Worker

Loading a WASM module inside a Web Worker is similar to loading it on the main thread. You fetch the .wasm file and instantiate it using WebAssembly.instantiate within the worker's script.

Once instantiated, you can call its exported functions to perform your heavy computations.

// worker.js
self.onmessage = async (e) => {
  // Fetch the WASM module
  const response = await fetch('my_wasm_module.wasm');
  const bytes = await response.arrayBuffer();
  
  // Instantiate the WASM module
  const { instance } = await WebAssembly.instantiate(bytes, {});
  
  // Call an exported WASM function
  const result = instance.exports.processData(e.data);
  
  // Send result back to the main thread
  self.postMessage(result);
};

Communicating with Workers

Communication between the main thread and a Web Worker happens via messages using the postMessage() method and the onmessage event handler.

Data passed between threads is copied, not shared, which means complex objects are serialized and deserialized. This ensures thread safety.

const workerCode = `
  self.onmessage = (e) => {
    console.log('Worker got:', e.data);
    self.postMessage('Processing ' + e.data);
  };
`;
const blob = new Blob([workerCode], { type: 'application/javascript' });
const worker = new Worker(URL.createObjectURL(blob));

worker.onmessage = (event) => {
  console.log('Main got:', event.data);
};

worker.postMessage('a large dataset');
worker.postMessage('another task');
console.log('Main thread sent messages.');

Offloading Heavy Calculations

This example demonstrates how to offload a simulated heavy calculation to a Web Worker. The main thread sends a number, the worker performs a Fibonacci-like calculation, and the main thread continues its work without interruption.

Imagine the worker's heavyCalculation function is actually your WASM module's high-performance function.

const workerCode = `
  self.onmessage = (e) => {
    console.log('Worker: Starting heavy calculation...');
    const num = e.data;
    let a = 0, b = 1, next;
    for (let i = 0; i < num; i++) {
        next = a + b;
        a = b;
        b = next;
    }
    console.log('Worker: Calculation finished.');
    self.postMessage(a);
  };
`;
const blob = new Blob([workerCode], { type: 'application/javascript' });
const worker = new Worker(URL.createObjectURL(blob));

worker.onmessage = (event) => {
  console.log('Main: Received result:', event.data);
};

worker.postMessage(40); // Send number to worker
console.log('Main: Sent request. UI remains responsive!');

// Simulate other UI work on the main thread
let counter = 0;
const intervalId = setInterval(() => {
  console.log('Main: UI update simulation ' + counter++);
  if (counter > 3) clearInterval(intervalId);
}, 100);

Key Advantages

Using Web Workers with WASM modules brings several significant benefits to your web applications:

Improved UI Responsiveness: The main thread stays free, preventing freezes.
Better Performance: Combine WASM's speed with parallel execution.
Enhanced User Experience: Users experience fluid interactions even during intensive tasks.
Efficient Resource Utilization: Leverage multi-core CPUs by distributing workload.

Check Your Understanding

Consider a web application that needs to perform complex image filtering. This process takes several seconds to complete.

Which approach would best ensure the user interface remains responsive?

Summary & Next Steps

We've learned how Web Workers provide a separate thread for executing scripts, preventing UI blocking. By loading and running your high-performance WASM modules inside these workers, you can achieve smooth, responsive web applications even with heavy computations.

This combination is powerful for tasks like image processing, data analysis, and complex simulations. In the next lessons, we'll explore more advanced concurrency patterns, including shared memory for even tighter integration.

자주 묻는 질문

“WASM 스레드를 활용한 Web Workers” 강의는 무료인가요?

네 — “WASM 스레드를 활용한 Web Workers” 전체 내용을 이 웹사이트에서 무료로 읽을 수 있습니다. 인터랙티브하게 실습하려면(내장 코드 에디터와 24/7 AI 튜터), CoddyKit PRO로 업그레이드하면 WebAssembly (WASM) for High Performance Apps 강의 전체를 잠금 해제할 수 있습니다. WebAssembly (WASM) for High Performance Apps 강의에는 총 4개의 강의가 포함되어 있습니다.

“WASM 스레드를 활용한 Web Workers”에서 뭘 배우나요?

Web Workers를 통합하여 별도의 스레드에서 WASM 모듈을 실행하고 UI 차단을 방지하여 응답성을 향상합니다. 브라우저에서 직접 실행하는 실습 코드로 WebAssembly (WASM) for High Performance Apps을(를) 배우며, 24/7 AI 튜터가 강의를 진행하면서 질문에 답변해줍니다.

WebAssembly (WASM) for High Performance Apps을(를) 시작하는 데 경험이 필요한가요?

사전 경험은 필요하지 않습니다. CoddyKit의 WebAssembly (WASM) for High Performance Apps은(는) 초급자부터 고급 학습자까지를 위해 구성되어 있으므로, 여기서 시작하거나 처음부터 시작할 수 있으며 자신의 속도대로 진행할 수 있습니다. 이것은 4개 중 1번째 강의입니다.

“WASM 스레드를 활용한 Web Workers” 강의는 얼마나 걸리나요?

대부분의 CoddyKit 강의는 약 5~10분이 소요됩니다. 각 강의는 간결하고 인터랙티브하여 꾸준한 진행이 가능하며, 웹과 앱에서 중단한 부분부터 바로 시작할 수 있습니다.

이 WebAssembly (WASM) for High Performance Apps 강의에서 코드를 작성하고 실행할 수 있나요?

네. 모든 WebAssembly (WASM) for High Performance Apps 강의에는 내장 코드 에디터가 포함되어 있으므로, 브라우저에서 바로 실제 코드를 작성하고 실행한 후 즉시 AI 피드백을 받을 수 있습니다 — 로컬 설정이 필요 없습니다.

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