[BUG] Comments not being removed in latest esbuild

[knaccc]

esbuild is not removing all comments. Simple test case:

input file (in.js) contents:

class MyClass {
  // first comment
  /* second comment */
}
// third comment
/* fourth comment */

esbuild --version
0.17.18
esbuild --outfile=out.js in.js

out.js contents:

class MyClass {
  // first comment
  /* second comment */
}

esbuild is removing the third and fourth comments, but not the first and second comments.

Curiously, using --minify does remove all 4 comments, but using --minify-identifiers leaves in the first and second comments.

[evanw]

Comments are removed when minifying: https://esbuild.github.io/api/#minify. Specifically with --minify-whitespace, since comments are a form of whitespace.

[knaccc]

@evanw thanks for your quick reply - perhaps it should be more of a feature request, then, for esbuild to always remove all comments? It caught me by surprise, because at first it seemed to be removing all of the comments when I used it in --minify-identifiers mode.

Then, luckily, I checked again and found that it was removing most of the comments instead of all of the comments.

It seems inconsistent to remove most rather than all, and it's also very useful to be able to use esbuild as a lightning-fast comment stripper instead of using a second tool for that. Thanks again for the incredible work you do.

[evanw]

It seems inconsistent to remove most rather than all

Some comments have been preserved because particular tools have particular semantics associated with them (e.g. #2721). All comments have not been preserved because doing so is a lot of work and it's not currently needed by any third-party tools that I have decided to commit to supporting.

it's also very useful to be able to use esbuild as a lightning-fast comment stripper instead of using a second tool for that

Sorry, esbuild is not a comment stripper. Code formatting is not an intended use case for esbuild. Other tools exist for that.

I'm closing this issue because I do not consider it to be a bug with esbuild.