Make it easier for bundlers to preserve the comment

[marjakh]

I'm told the annotation syntaxes for telling esbuild which comments to preserve are:

//! somecomment
and
// somecomment @preserve.

We probably don't want to add //! in addition to //#, to keep this consistent with source maps.

But what we could easily do is allow random stuff:
//# allFunctionsCalledOnLoad <stuff>
and
//# functionsCalledOnLoad=<data> <stuff>

[callie-openai]

Hey thanks @marjakh, yes the syntax comes from https://esbuild.github.io/api/#legal-comments.

A "legal comment" is considered to be any statement-level comment in JS or rule-level comment in CSS that contains @license or @preserve or that starts with //! or /*!. These comments are preserved in output files by default since that follows the intent of the original authors of the code. However, this behavior can be configured by using one of the following options:

inline
Preserve all legal comments.

My strategy was to use the rollup banner option and the @preserve but I'd just as happily use the other strategies. I was planning on adding it to the top of our react dom specific bundle to hopefully speed up hydration / rendering times.

fwiw here's the docs on rollup syntax for the banner: https://rollupjs.org/configuration-options/#output-banner-output-footer