Bun.build preserve important comments

[ElYaiko]

What is the problem this feature would solve?

Preserving important comments like licenses when using Bun.build

What is the feature you are proposing to solve the problem?

Adding a flag so comments starting with /**! will be preserved.

What alternatives have you considered?

https://esbuild.github.io/api/#legal-comments

[TomasHubelbauer]

IMO having an option for preserving all comments would also be beneficial. Function.toString() will display internal comments so removing them is kind of a breaking change as it changes the result of the toString and while this doesn't affect a lot of people, with preserved comments you can do some nifty things so it would be nice to have that option.

[busybox11]

This feature could be really useful to me as a userscript developer.
Every userscript has to begin with a // ==UserScript== section, ending by // ==/UserScript==. I'm trying to move my Vanilla JS scripts to TS projects, by running Bun.build as a build step. This could really be beneficial for me as well.

[RiskyMH]

It's interesting that bun build preserves //! comments but not /*! like esbuild. @paperdave, would it make sense for Bun to handle this for consistency, or maybe introduce a flag to control comment preservation like esbuild does for legal comments?

[paperdave]

Yes. See #8727 (this issue is kind of a duplicate of that but theres some new ideas here so i think we can leave it open)

I think in addition to //! it would be nice to support // ==UserScript== as well, but an alternative to that would be using the newly added --banner option (available on canary right now, and in the next release).

IMO having an option for preserving all comments would also be beneficial.

Ideally, build without --minify-whitespace could do that. I don't know how hard it would be to add.