Breaks any other libraries that rely on window

[ChuckJonas]

Pretty much any other library that does a if(window) check will no longer operate as expected if you install this.

[gregw]

please explain a bit more?

[ChuckJonas]

this library "patches" cometd by adding window to the global scope...

There might be another library (@salesforce/core or jsforce for example), that checks window to determine if it is running in a browser or not.

After patching, this library will think it's operating in a browser, and likely break.

I know this because that's exactly what happened when I required this package before running this code from @salesforce/core

const connection: Connection = await Connection.create({
   authInfo: await AuthInfo.create({ username: 'john@example.com'})
});
let org = await Org.create({connection});
org.refreshAuth();

[ChuckJonas]

I guess you could say jsforce is equally to blame here. https://github.com/jsforce/jsforce/blob/master/lib/transport.js#L29

[sbordet]

@ChuckJonas so what suggestions do you have to avoid this?

cometd.js needs a bunch of functions that are provided by the window object on browsers, and by the global object in Node.
In addition when running on Node I need to "fake" other functions (such as XMLHttpRequest) - this is currently done by adapt().

I can pollute the global object in Node with the functions that I need (apparently this is what others are doing, e.g. mocha).

Alternatively I can pollute the window (in browsers) and the global (in Node) object with a single property object, say cometdExternals, and then modify cometd.js to assume that a cometdExternals object exist rather than relying on window.
How does that sound?

[ChuckJonas]

I think that makes...

Although I'm wondering if you're going to change the cometd core anyways, why not just make the library itself isomorphic?

Seems like setTimeout, console, and clearTimeout could be resolved simply by first checking if they exist and then using window.setTimeout, if needed.

You could do the same with XMLHttpRequest by conditionally requiring it from this pkg (or maybe even just use this npm package.

[sbordet]

I need some adapter code anyways for 2 reasons:

1. Node's console does not have a debug() function, while browsers do.
2. I really need XMLHttpRequest as provided, I cannot put a require() in the core cometd.js code.

Especially for the latter, again I can pollute the global object, or I can assume there exist a cometdExternals object.
When used in a browser, cometdExternals = window, otherwise I will make a cometdExternals in adapt() and only pollute the global object with it: global.cometdExternals = ....

When supporting WebSocket on the client side I would just need to do cometdExternals.WebSocket = require('ws');.

Makes sense?

[ChuckJonas]

I believe you could do something like this:

if(isNode){
   require('XMLHttpRequest');
}

Alternatively, tools like browserfy and webpack allow you to require package in browser modules.

But I understand the hesitation to muddy the core implementation.

Seems like the solution you've outline above should work...

Thanks for being responsive!

[sbordet]

@ChuckJonas yeah, there are users that don't use CommonJS but AMD, others that just rely on vanilla JavaScript 4, etc. so I can't really muddy the core implementation.

I'm experimenting with my outlined solution above and seems to be working.

[sbordet]

Turns out this fix breaks other libraries.