When thread-loader is working, do the those threads read the options of the other loaders?

[nyngwang]

There are some caveats listed in README.md of thread-loader. Specifically, my concern around it is the first rule and the third rule:

Loaders running in a worker pool are limited. Examples:

Loaders cannot emit files.
Loaders cannot use custom loader API (i. e. by plugins).
Loaders cannot access the webpack options.

Confusion on Rule 1

Isn't that babel-loader also emitting files for webpack eventually? In the example given in the readme, it mentioned that it is expected to work with babel-loader. I need some clarifications here as I have some misunderstandings.

Confusion on Rule 3

In my case, I'm using babel-loader with some custom options like rootMode: 'upward', and in my babel.config.js I also included some third-party plugins like react-refresh/babel for HMR with the corresponding plugin in my webpack.config.js. Does this rule mean that babel-loader could not access these plugins?

[alexander-akait]

Isn't that babel-loader also emitting files for webpack eventually?

No, files - i.e. assets, emit assets, babel-loader returns code - i.e. string

Does this rule mean that babel-loader could not access these plugins?

No, it is not related to babel plugins at all

[nyngwang]

The first answer is helpful. I'm still not sure whether some of the options passing to babel-loader would be ignored by thread-loader. I have spent much time reading GitHub Issues on thread-loader but I'm still confused. It seems that for a worker(thread) to access webpack's options, these options need to be serializable. Is this correct? Thank you.

[alexander-akait]

All primitive types will be work and serialized

[nyngwang]

@alexander-akait I think this should be documented on README.md of thread-loader, I got the same conclusion similar to what you said here by reading those closed/open issues. From the current wording, it says:

Loaders cannot access the webpack options.

Sincerely.

[alexander-akait]

Yeah, feel free to sens a PR