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GitHub - pshihn/workly: A really simple way to move a stand-alone function/class...

 6 years ago
source link: https://github.com/pshihn/workly
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README.md

Workly ?️‍♀️→ ?

  • A really simple way to move a stand-alone function/class to a worker thread.
  • All calls are made asynchronous. Works great with async/await.
  • Only 1.3kb gzipped.

Install

Download the latest from dist folder

or from npm:

npm install --save workly

Usage

Moving a function to a worker is really simple.

function busyAdd(a, b) {
  let st = Date.now();
  while (true) {
    if ((Date.now() - st) > 2000) break;
  }
  return a + b;
}

(async () => {
  let workerAdd = workly.proxy(busyAdd);
  console.log(await workerAdd(23, 16)); // 39
})();

Or, in fact a Class

class Adder {
  constructor() {
    this.count = 0;
  }
  add(a, b) {
    this.count++;
    return a + b;
  }
}

(async () => {
  let WAdder = workly.proxy(Adder);
  let a = await new WAdder();
  console.log(await a.count); // 0
  console.log(await a.add(23, 16)); // 39
  console.log(await a.count); // 1
})();

Custom workers

The above examples only work when the class/function is not dependent on the containing scope, i.e. other libraries or global objects. But, you can create a custom worker.js file and move the code in there. In the worker, you can expose your object/function/class using workly.expose method.

In this example, the function depends on moment.js

worker.js

importScripts('https://cdn.jsdelivr.net/npm/[email protected]/moment.min.js', '../dist/workly.min.js');
function friendlyTime(value) {
  return moment(value).calendar(null, {
    sameDay: function (now) {
      if (now - this < 1000 * 60) {
        return "[Just now]";
      } else if (now - this < 1000 * 60 * 60) {
        return "[" + Math.round((now - this) / (1000 * 60)) + " mins ago]";
      } else {
        return '[Today at] LT'
      }
    }
  });
}
workly.expose(friendlyTime);

main.js

(async () => {
  let w = workly.proxy("./worker.js");
  let now = Date.now();
  console.log(now);
  console.log(await w(now));
  console.log(await w(now - (24 * 60 * 60 * 1000)));
  console.log(await w(now - (4 * 24 * 60 * 60 * 1000)));
})();

Caveats

  • If you're not using a custom worker, the function/class being pushed to the worker cannot depend on the containing scope.
  • Since workers do not have access to DOM, DOM manipulation is not supported.
  • Objects passed into functions are not passed by reference, so if the function in the worker updates the passed in object, it will not affect the object in the main scope.

Examples

See the examples folder

License

MIT License (c) Preet Shihn


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