Support `resolveImportMeta` hook

[underfin]

The resolveImportMeta hook gives a way to allows to customize import.meta and import.meta.someProperty, see here
https://rollupjs.org/plugin-development/#resolveimportmeta. Here has a example for it.

function importMetaUrlCurrentModulePlugin() {
	return {
		name: 'import-meta-url-current-module',
		resolveImportMeta(property, { moduleId }) {
			if (property === 'url') {
				return `'${pathToFileURL(moduleId).href}'`;
			}
			if (property == null) {
				return `{url:'${pathToFileURL(moduleId).href}'}`;
			}
			return null;
		}
	};
}

The hook will return string code to replace original import.meta.xx. Because the rolldown using Ast to codegen. It is difficult to implement it, it need to the oxc has some ways create ast from string, we could using parse at now. If you has good ideas, please let me know.

[hyfdev]

It seems to be just a short-cut of transform hook. We could support it natively, since we would have transform step in the future for DCE and variables replacement.

However, supporting this requires us to call JsCallback while transforming. I intend not to and wonder if there are other solutions/workarounds.

[sapphi-red]

resolveImportMeta (and resolveFileUrl) runs after the chunk generation and before the chunk is transformed into other formats (e.g. CJS, SystemJS).
There are cases where it's not easily possible to achieve by transform hook.

For example, if you want to change import.meta.url to be /custom/${chunkName} and going to output in CJS:

• this cannot be done by transform hook, because chunkName is not determined at that time
• this cannot be done by renderChunk hook, because import.meta.url is already replaced with (typeof document === 'undefined' ? new (require('u' + 'rl').URL)('file:' + __filename).href : (document.currentScript && document.currentScript.src || new URL('main.js', document.baseURI).href)) by rollup at that time
  • you can try to replace the replaced code but it'd be fragile

[sapphi-red]

Hmm, maybe adding an option that tells rollup to stop transforming import.meta even when outputting in other formats would make resolveImportMeta hook to be replaced with renderChunk hook.

[sapphi-red]

Ah, no, that will make it impossible to know both moduleId and chunkId at the same time. You can only know the chunkId in renderChunk and moduleId in transform. Well, precisely you could get the moduleId in renderChunk by using sourcemaps though.

[cyans-nya]

Have this been working on now?