docs: [api] packageImportsExportsResolve

Signed-off-by: Lexus Drumgold <unicornware@flexdevelopment.llc>

Author: unicornware

README.md

@@ -476,9 +476,43 @@ Implements the [`PACKAGE_EXPORTS_RESOLVE`][algorithm-package-exports-resolve] al
 
 <!--lint enable-->
 
+Resolve a package export or import.
+
 Implements the [`PACKAGE_IMPORTS_EXPORTS_RESOLVE`][algorithm-package-imports-exports-resolve] algorithm.
 
-**TODO**: `packageImportsExportsResolve`
+> 👉 **Note**: Returns a promise if
+> [`packageTargetResolve`](#packagetargetresolvetpackageurl-target-subpath-patternmatch-isimports-conditions-mainfields-parent-fs),
+> returns a promise.
+
+#### Type Parameters
+
+- `T` ([`Awaitable<URL | null | undefined>`](#awaitablet))
+  — the resolved package export or import url
+
+#### Parameters
+
+- `matchKey` (`string`)
+  — the package subpath extracted from a module specifier, or a dot character (`.`)
+- `matchObject` ([`ExportsObject`][pkg-exports-object] | [`Imports`][pkg-imports] | `null` | `undefined`)
+  — the package exports or imports
+- `packageUrl` ([`ModuleId`](#moduleid))
+  — the url of the directory containing the `package.json` file
+- `isImports` (`boolean` | `null` | `undefined`)
+  — whether `matchObject` is internal to the package
+- `conditions` ([`List<Condition>`](#condition) | `null` | `undefined`)
+  — the list of export/import conditions
+  - **default**: [`defaultConditions`](#defaultconditions)
+- `mainFields` ([`List<MainField>`](#mainfield) | `null` | `undefined`)
+  — the list of legacy main fields
+  - **default**: [`defaultMainFields`](#defaultmainfields)
+- `parent` ([`ModuleId`](#moduleid) | `null` | `undefined`)
+  — the url of the parent module
+- `fs` ([`FileSystem`](#filesystem) | `null` | `undefined`)
+  — the file system api
+
+#### Returns
+
+(`T`) The resolved package export or import URL
 
 <!--lint disable-->
 
@@ -1295,8 +1329,12 @@ community you agree to abide by its terms.
 
 [node-esm]: https://nodejs.org/api/esm.html
 
+[pkg-exports-object]: https://github.com/flex-development/pkg-types/blob/main/src/exports-object.ts
+
 [pkg-imports-subpath]: https://github.com/flex-development/pkg-types/blob/main/src/imports-subpath.ts
 
+[pkg-imports]: https://github.com/flex-development/pkg-types/blob/main/src/imports.ts
+
 [pkg-package-json]: https://github.com/flex-development/pkg-types/blob/main/src/package-json.ts
 
 [subpath-imports]: https://nodejs.org/api/packages.html#subpath-imports

docs/resolution-algorithm.md

@@ -146,7 +146,22 @@ The resolver can throw the following errors:
 
 <!--lint enable-->
 
-**TODO**: `PACKAGE_IMPORTS_EXPORTS_RESOLVE`
+1. If `matchKey` is a key of `matchObj` and does not contain `'*'`, then
+   1. Let *target* be the value of `matchObj[matchKey]`
+   2. Return the result of [`PACKAGE_TARGET_RESOLVE(packageUrl, target, null, isImports, conditions, mainFields, parent)`][package-target-resolve]
+2. Let *expansionKeys* be the list of keys of *matchObj* containing only a single `'*'`, sorted by the sorting function
+   [`PATTERN_KEY_COMPARE`][pattern-key-compare] which orders in descending order of specificity
+3. For each key *expansionKey* in *expansionKeys*, do
+   1. Let *patternBase* be the substring of *expansionKey* up to but excluding the first `'*'` character
+   2. If *matchKey* starts with, but is not equal, to *patternBase*, then
+      1. Let *patternTrailer* be the substring of *expansionKey* from the index after the first `'*'` character
+      2. If *patternTrailer* has zero length, or if *matchKey* ends with *patternTrailer* and the length of *matchKey*
+         is greater than or equal to the length of *expansionKey*, then
+         1. Let *target* be the value of `matchObj[matchKey]`
+         2. Let *patternMatch* be the substring of *matchKey* starting at the index of the length of *patternBase* up to
+            the length of *matchKey* minus the length of *patternTrailer*
+         3. Return the result of [`PACKAGE_TARGET_RESOLVE(packageUrl, target, patternMatch, isImports, conditions, mainFields, parent)`][package-target-resolve]
+4. Return `null`
 
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