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
// the busyAdd is executed in a worker so
// the UI does not get blocked
})();
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(); // instance created/running in worker
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/moment@2.20.1/moment.min.js', '../dist/workly.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.