Generate correct manifest

[izaera]

Bundler 3 is not generating flags and information for modules in manifest.json any more. We should do it (or at least know if it is OK that it is missing) to maintain backwards compatibility.

[jbalsas]

I'd start by know if it is OK that it is missing... it's always been hard for my to figure out wether this is needed or not...

[izaera]

I think we will be lucky, because it was mostly needed for the ES6 module flags hack (the loader needed to know in advance if a module was transpiled from ES6). But now that we are bundling everything with webpack, I think that's not needed any more.

However, I'm still investigating.

[izaera]

Right now we are using the manifest.json for two things:

1. Add module flags (as per Add support for writing module metadata in manifest.json #368): needed for circular dependencies, but can be used as a general mechanism to pass metadata regarding modules from the JS Toolkit directly to the NPM Registry.
2. Map namespaced module names: for example react to frontend-js-web-react$react.

I think 2 was needed for the bridges functionality, which mapped unversioned package names to a specific version to maintain backwards compatibility with the pre-bundler architecture.

As far as I can tell, we don't need 1 because we can't have circular dependencies in the current setup. I'm unsure if we could end up having circular deps via imports, but I think we can delay that and, if it happens, we just need to add the necessary flags to the manifest.json file.

Regarding 2, it is normally not needed, but any module using bridges will need the manifest to be present so I would say we should generate it as in bundler 2, at least until we get rid of bridges...

Any thoughts? @jbalsas @wincent

[izaera]

Just to give an example of 2: frontend-js-web declares bridges in the .npmbridgerc file to map all the frontend-js-web/liferay/* modules to an unversioned name, so that people can do:

Liferay.Loader.require('frontend-js-web/liferay/events')

without any need to specify the current frontend-js-web version like in:

Liferay.Loader.require('[email protected]/liferay/events')

[wincent]

Regarding 2, it is normally not needed, but any module using bridges will need the manifest to be present so I would say we should generate it as in bundler 2, at least until we get rid of bridges...

IIUC, that sounds reasonable.