Add WebWorker Support

[dansiviter]

Add ability to load WebWorkers (and SharedWorkers?) via the react-scripts. My use-case is for using latency (and debug) sensitive protocols over WebSocket which may get dumped by the server if no activity occurs.

There has been a lot of discussion regarding this on #1277 but no definitive answer and now closed. Also, I'm a server-side dev so JavaScript PR is not my forte, and neither is ejecting the scripts as that looks scary.

[gaearon]

I’m not opposed if we see a clear proposal from someone about how they should work.

[viankakrisna]

I haven't written WebWorkers before, but I think this library is interesting to get support of web workers in CRA right now: https://github.com/developit/workerize

it also has it's own webpack loader https://github.com/developit/workerize-loader (not required to use workerize)

which in turn inspired by https://github.com/webpack-contrib/worker-loader

I think adding the last one with test like .worker.jswould be a good option if we want to support it out of the box without tying it with any library (except webpack?)

[iansu]

workerize seems like a more straight forward solution. It looks like it handles the communication between the parent thread and the worker, which is nice. You just have to export a method from the worker as opposed to using postMessage/onmessage to communicate between the two.

I like the idea of using a different extension (.worker.js) to signify a worker and having it registered automatically. That seems to fit nicely with create-react-app.

[iansu]

I'm curious about WebWorkers in general so I wouldn't mind giving this a try.

[wregis]

In the past I had to eject and configure "worker-loader". I used it to process some routines on datasets and still allow users to interact with the main UI.

[doxxx]

I use Web Workers to implement a solver using genetic algorithms for a SPA. The solver can run for up to a minute or two, so it needs to be in a "background thread" -- i.e. Web Worker -- to not freeze the browser page while it's running.

I should note that my app is currently implemented in Angular and plain old ES5-ish Javascript. I would like to migrate to React and Typescript but this has been a stumbling block so far.

[jlarmstrongiv]

Is there anything that needs to be done before this pull request can be merged into the next branch (2.0 release)? I might have missed it, but I could not find Web Workers on the 2.0 Projects roadmap. I would love to be able to try it out in one of the alpha releases 🙂

[iansu]

I think there's still some debate about using worker-loader vs. workerize-loader. worker-loader is more low-level and powerful but workerize-loader is incredibly easy to use and probably covers the majority of use-cases.

[doxxx]

I couldn't get workerize-loader to work with Typescript, but I may have simply failed at the appropriate incantations.

[Narvey]

@iansu I'm not sure about workerize-loader covering the majority of use-cases. Unless I'm understanding incorrectly, it doesn't allow sending messages in the middle of a loop (this is extremely important for making realistic progress bars).