add 'includeCoreModules' option

[tjenkinson]

Setting includeCoreModules: false makes it possible to resolve as if the core modules did not exist.

This can be useful in a bundler like rollup where the user may be targeting web, where node builtins are not relevant.

Refs rollup/plugins#637

[ljharb]

This has usually been achieved via https://www.npmjs.com/package/browser-resolve - it seems much better for rollup to just use that package rather than adding complexity to resolve and reinventing decade-built wheels?

[tjenkinson]

Hey @ljharb !

Thanks for pointing out browser-resolve. Agree it would be best not to duplicate logic where possible.

I think this PR is still useful though and enables a feature I think browser-resolve currently doesn't have.

If I'm bundling for web, I want to guarantee that core modules aren't used. I think with browser-resolve you'd have to provide something for all the builtins on modules?

Also if I import fs I'd like that to load the node_modules version automatically without having to make it fs/.

[ljharb]

Yes, any bundler for node modules must provide shims for node core modules, otherwise it's broken (like webpack 5 is currently broken, for example). That allows, for example, importing fs to transparently map to the shim (not that most fs things are shimmable in browsers, ofc) without the trailing slash. This is what browser-resolve does.

If you're trying to deny access to a core module that could be shimmed in a browser (which, for a node module bundler, would mean it's broken) you should already be able to do this in resolve via a combination of callback options, which is how browser-resolve does it.

[tjenkinson]

If you're trying to deny access to a core module that could be shimmed in a browser (which, for a node module bundler, would mean it's broken) you should already be able to do this in resolve via a combination of callback options, which is how browser-resolve does it.

Yeh this is what I meant.

If you do

browserResolve.sync('fs')

This returns fs, when I think a module not found error would be preferable, or the absolute path to the fs package in node_modules if there was one.

[ljharb]

hmm, interesting. I do see how resolve simply doesn't permit you to override the "isCore" logic, and always returns core module names directly.

This seems reasonable to add, thanks for bearing with me.

[tjenkinson]

Thanks!

[ljharb]

Released in v1.19.0; it'll also be included in the next v2 prerelease.