I am using this Web worker which has a Global variable declared in it. Can I access the same (Global variable in worker 1) in the newly spawned web worker(worker 2)?
When I've tried using jQuery in web worker, I get error "window is not defined". Is there any way to use jQuery in a Web Worker?
importScripts('jquery-latest.js'); function fetch_ajax(url) { $.ajax({ type: 'GET', url: url, success: function(response) { postMessage(response); } }); } fetch_ajax('test.txt'); Web Workers don't have a window object.
To access global state, use self instead, code that will work on both the main thread and the worker thread.
But note that you still won't be able to access or manipulate the parent DOM (e.g. get window.jQuery via self.jQuery).
While the main thread window self points to the Window object, in worker threads self points to a separate WorkerGlobalScope object.
PostMessage method and onmessage event). Access to DOM or some shared variables would result in lots of nasty errors...
self object. In the main thread, self is a synonym for window. Is this your understanding as well, or did you mean something else?
self property of a global object basically returns this (perhaps not literally, but conceptually). So, window.selfreturns window, and self inside a Web Worker returns the global object of the worker (whatever that's called).Based on @buley tip, I did it:
var window = self; importScripts(/* dependencies here */); /* my code */ In my case I was trying to use the ES6-Promise lib: https://github.com/jakearchibald/es6-promise#readme
typeof window !== 'undefined' to check if I am in a web worker, or in the main client-side JavaScript. It wouldn't work anymore.
Instead of global variables in web workers, you should use postmessage & onmessage api for information exchange between web workers.
Regarding your jQuery issue, jQuery is for Dom manipulation and Dom isn't available to web workers. I think you need to change your approach. However, if you insist on using jQuery in the web worker you can try something like what is explained at: https://anandabandaru.wordpress.com/2019/06/21/use-jquery-inside-html5-web-worker/
Since web workers deal with threading, they want to simplify things by blocking access to shared variables i think so they don't have to deal with synchronizing different processes when they access the same variables.
The closest you can get to "global" is BroadcastChannel.
this runs on global channel identifiers, then you can listen to pub/sub on these.
const channel = new BroadcastChannel('my_channel'); channel.postMessage({ question: "what is the value of the variable" }); channel.onmessage = function (e) { console.log('Received read ', e.data); }; The cool thing is you can subscribe or send messages on "my_channel" anywhere.
