No WebWorker support

[mpfau]

There are three window and two document references spread through systemjs-hmr and systemjs-hot-reloader:

• https://github.com/alexisvincent/systemjs-hmr/blob/master/lib/index.js#L13
• https://github.com/alexisvincent/systemjs-hmr/blob/master/lib/index.js#L17
• https://github.com/alexisvincent/systemjs-hot-reloader/blob/master/lib/index.js#L54
• https://github.com/alexisvincent/systemjs-hot-reloader/blob/master/lib/index.js#L10
• https://github.com/alexisvincent/systemjs-hot-reloader/blob/master/lib/index.js#L17

However, even after removing them, hot-reloading from a worker does not work.

The update event seems to be triggered correctly and systemjs-hot-reloader logs:

reloading src/updatedModule.js
reloading cache.json

However, the updated module is not re-evaluated (break points are not hidden/console.log statements are not printed).

Unfortunately, I couldn't find the source of the problem... :(

[mpfau]

Just digged a bit deeper in it. The base functions (System.unload and System.import) are also functional in the worker. Modules are successfully re-imported when manually triggering System.unload and System.imports in a worker context, too.

However, when system-hmr is not able to detect the right entries. That means that a changed module gets unloaded by system-hmr but not imported again, as its module is not a dependency of the entries that are identified by system-hmr.

@alexisvincent Is there a way to provide the entries to systemjs-hot-reloader (https://github.com/alexisvincent/systemjs-hmr/blob/master/lib/index.js#L223)?

[alexisvincent]

yeah, System.reload('someModule', {entries: ["entry"]}). Will give a better explanation when I'm not on my phone

[alexisvincent]

@mpfau Having a look now,

The following might not be necessary.

• https://github.com/alexisvincent/systemjs-hmr/blob/master/lib/index.js#L13
• https://github.com/alexisvincent/systemjs-hmr/blob/master/lib/index.js#L17

This is legacy and only there for backwards compatibility.

• https://github.com/alexisvincent/systemjs-hot-reloader/blob/master/lib/index.js#L54

These are needed if we want full page reload and automatic host detection.

• https://github.com/alexisvincent/systemjs-hot-reloader/blob/master/lib/index.js#L10
• https://github.com/alexisvincent/systemjs-hot-reloader/blob/master/lib/index.js#L17

Is what you're wanting to achieve here being able to hot reload web worker scripts. Or run the hot-reloader in a web worker?

As I said before, you can manually provide entries, but then no entry discovery will happen. This could change in the future if it's more useful to merge entries.

Manually specifying entries is achieved as follows

System.reload('someModule', {entries: ["entry"]})

[mpfau]

@alexisvincent full page reload is not possible from a worker anyways. Could be wrapped in a if (typeof window !== 'undefined').

I'm currently trying to run the hot-reloader in a webworker. However, I think that both approaches (reload the worker script if a module loaded by that script is modified (1) / updating a script in the webworker on module change (2)) are valid depending on your use-case.

Manually specifying the entries only works when systemjs-hmr is used directly. What do you think about an entries option for systemjs-hot-reloader?

[alexisvincent]

@mpfau Yeah could totally add entries as an option to the connect function.

in terms of window detection, this could probably be generalized to an environment detection. Eg. web, web-worker, node etc. Then we can do the following:

if (isNode) {
    ...
} else if (isWorker) {
    ...
}

[alexisvincent]

@mpfau Have pushed entries option in connect function. See if that works for you.

[mpfau]

@alexisvincent thanks! This is working fine and enables an absolutely awesome workflow :)

I created a the pull requests alexisvincent/systemjs-hmr#23 and #132 in order to enable systemjs-hmr and systemjs-hot-reloader for worker usage.

[alexisvincent]

@mpfau are there any real benefits to running the hot-reloader in a web worker by default?

[alexisvincent]

@mpfau Can you give me a short description of what the current codebase can do with regards to web workers. Would like to add something to the README

[mpfau]

I am working on a description. Give me a few more minutes... :)

[mpfau]

#137