Welcome to Comlink: Empowering Web Workers with Seamless API Integration
Comlink is an efficient library designed to leverage Web Workers in JavaScript by providing a seamless mechanism for RPC-like communication. If you wish to easily offload heavy computations to background threads without getting bogged down in complex inter-thread communication, Comlink is your go-to solution.
Why Comlink?
Modern web applications demand higher performance and better responsiveness. Comlink addresses this by easing the creation and management of Web Workers, allowing you to execute complex computations in the background and keep the main thread free for UI interactions.
Getting Started
Firstly, you need to install Comlink:
npm install comlink
Basic Usage
Creating a simple Web Worker using Comlink:
// worker.js
import * as Comlink from 'comlink';
const api = {
async heavyComputation(input) {
// Simulate heavy computation with a delay
return new Promise(resolve => setTimeout(() => resolve(input * 2), 2000));
}
};
Comlink.expose(api);
// main.js
import * as Comlink from 'comlink';
const worker = new Worker('worker.js');
const workerApi = Comlink.wrap(worker);
(async () => {
const result = await workerApi.heavyComputation(42);
console.log(result); // 84
})();
Advanced API Usage
Comlink provides a plethora of APIs for more advanced use cases:
Transferring Ownership
async function createBuffer() {
return new Uint8Array([1, 2, 3, 4, 5]);
}
const api = {
async getBuffer() {
const buffer = await createBuffer();
return Comlink.transfer(buffer, [buffer.buffer]);
}
};
Comlink.expose(api);
Proxies
const state = Comlink.proxyValue({count: 0});
const api = {
increment() {
state.count++;
},
getState() {
return state;
}
};
Comlink.expose(api);
An Example Application
Let’s create a simple example application that leverages Comlink for background processing:
// worker.js
import * as Comlink from 'comlink';
const api = {
async fetchUserData(userId) {
const response = await fetch(\`https://jsonplaceholder.typicode.com/users/\${userId}\`);
return response.json();
}
};
Comlink.expose(api);
// main.js
import * as Comlink from 'comlink';
const worker = new Worker('worker.js');
const workerApi = Comlink.wrap(worker);
async function displayUserData(userId) {
const userData = await workerApi.fetchUserData(userId);
document.getElementById('output').textContent = JSON.stringify(userData, null, 2);
}
document.getElementById('fetchButton').addEventListener('click', () => {
const userId = document.getElementById('userId').value;
displayUserData(userId);
});
With this setup, clicking the “fetch” button fetches and displays the user data without blocking the main thread:
// index.html
<!DOCTYPE html>
<html>
<body>
<input id="userId" type="number" placeholder="Enter User ID">
<button id="fetchButton">Fetch User Data</button>
<pre id="output"></pre>
<script src="main.js"></script>
</body>
</html>
With Comlink, the complexity of handling Web Workers is significantly reduced, letting you focus on the core functionality of your application.
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