Thread

Thread is a base class for running CPU-bound work on a background thread (a Web Worker). Extend it, override run() and onMessage(), then call start().

import { Thread } from "jops-core";

Learn more: Threads.

Methods to override

run()

run(params: any): void

The work the thread performs. It runs inside the Web Worker, so it must be self-contained: it has no access to the outer scope, imports or the class instance (this). Send results back with self.postMessage(result).

Parameters

params: the value passed to start().

onMessage()

onMessage(event: MessageEvent): void

Runs on the main thread for every message the worker posts with self.postMessage(). The result is in event.data.

Instance methods

start()

start(params?: any): void

Spawns the Web Worker, runs run(params) in it, and routes its messages to onMessage().

Parameters

params (optional): data passed to run(params) inside the worker. It is copied to the worker, so it must be serializable (plain objects, arrays, strings, numbers…).

terminate()

terminate(): void

Stops the worker immediately and clears the internal reference. Safe to call when the worker has already finished (it only logs a warning when no worker was started). After terminate(), start() can spawn a new worker.

Example

import { Thread } from "jops-core";

export default class HashThread extends Thread {
  run(params) {
    // runs on a background thread: no access to the main thread or the instance
    let hash = 0;
    for (let i = 0; i < params.data.length; i++) hash ^= params.data.charCodeAt(i);
    self.postMessage(hash);
  }
  onMessage(event) {
    console.log("Hash result:", event.data);
  }
}

const t = new HashThread();
t.start({ data: "hello world" });
// later:
t.terminate();