Reverse `imports` / `exports` expanding keys priorities

[PaperStrike]

Bug Report

🔎 Search Terms

imports priority, exports priority, imports order, exports order, imports lookup, exports lookup, multi imports, multi exports

🕗 Version & Regression Information

• This changed between versions 4.5 and 4.7
• This is the behavior in every version I tried, and I reviewed the FAQ for entries about Node12

⏯ Playground Link

Not applicable

💻 Code

Given file ./test/setup.ts, file ./src/lib/Service.ts, and ./package.json:

{
  "imports": {
    "#test/*": "./test/*.js",
    "#lib/*": null,
    "#*": "./src/*.js",
  }
}

🙁 Actual behavior

TS can't find #test/setup, but can find #lib/Service. I debugged and found here, in loadModuleFromImportsOrExports,

TypeScript/src/compiler/moduleNameResolver.ts

Lines 2074 to 2075 in 6cda20d

	const expandingKeys = sort(filter(getOwnKeys(lookupTable as MapLike<unknown>), k => k.indexOf("*") !== -1 || endsWith(k, "/")), (a, b) => a.length - b.length);
	for (const potentialTarget of expandingKeys) {

TS sorts the expanding keys from short to long before the loop. So the first potentialTarget is #*, and it matches both, resolving to ./src/test/setup.ts and ./src/lib/Service.ts. It's very likely that it sorts in the reverse way.

🙂 Expected behavior

• For #test/setup, TS tests #test/* first, and resolves to ./test/setup.ts.
• For #lib/Service, TS tests #test/* first, not matched, then tests #lib/*, resolves to null, goes to the null branch in loadModuleFromTargetImportOrExport and returns undefined.

The same algorithm applies to exports field.

[PaperStrike]

As a reference, Node.js uses patternKeyCompare to find the longest "bestMatch" to use. See node/resolve.js, L691, packageExportsResolve, and L776, packageImportsResolve.

The usage of null is documented in Subpath patterns · Modules: Packages | Node.js v18.2.0 Documentation.

Currently TS is sorting them in the reverse way, and thus lacking support for sub-subpath patterns that use null or point to another target.

[MartinJohns]

If I understand and tested correctly, writing #*/ works, but writing #* does not.

This is also the syntax mentioned here: https://nodejs.org/api/packages.html#package-entry-points

As a last resort, package encapsulation can be disabled entirely by creating an export for the root of the package "./*": "./*"

[PaperStrike]

@MartinJohns The problem is not about exporting everything, it's about TypeScript should choose the most specific matching pattern.

[PaperStrike]

I've already prepared a fix and a test case for this in https://github.com/PaperStrike/TypeScript/tree/imports-exports-pattern-order, by that you may better get what this is about.