Generated modules export unnecessary symbols about scala-js HOT 4 CLOSED

I can see how this might be a problem even with a full blown bundler: The bundler will not make the distinction between internal and public modules, as such, it might leave exports around unnecessarily.

@scf37 could you actually observe unnecessary export statements in bundled output (I'm not sure I'd count Uglfy as a bundler)?

Scala.js does not have the goal to generate shipping ready JS code. It is expected that a downstream bundler is run.

More specifically: Scala.js does make no attempt to generate optimal modules. It merely generates modules with sufficiently granular structure so general-purpose JS bundlers can take advantage of it. But it is expected that the module structure is still changed / optimized after Scala.js is run.

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could you actually observe unnecessary export statements

Yep. AFAIK GCC simple mode run independently on every file with --assume_function_wrapper still produces the best results. Writing simple script to analyze dependencies and comment out unused exports decreases output module size significantly (for simple scalajs project, 306K -> 217K after GCC).

No big deal to write such transformer btw but I guess it could be easy fix on your side.

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AFAIK GCC simple mode run independently

Ah, yes. That's expected. I meant if you observe unnecessary exports if you run a bundler that optimizes the whole program / all the modules.

it could be easy fix on your side.

Not really :-/ Basically, when generating, say a function, in a module, we do not (trivially) have tracking information of whether this function is only used by this module (no export) or also other modules, (must export). Tracking this comes at a cost, especially in an incremental scenario where this information can change non-locally (another module started using it, so now it must be exported, even though it didn't change).

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I have checked that vite (when set-up like in the tutorial) is able to fully remove all the exports when bundling.

Therefore and in combination with #4977 (comment), I'm going to close this as-designed.

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