module: subpath folder mappings EOL

PR-URL: #40121
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Bradley Farias <bradley.meck@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

Author: guybedford

doc/api/deprecations.md

@@ -2707,6 +2707,9 @@ Use `fs.rm(path, { recursive: true, force: true })`,
 ### DEP0148: Folder mappings in `"exports"` (trailing `"/"`)
 <!-- YAML
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/40121
+    description: End-of-Life.
   - version: v16.0.0
     pr-url: https://github.com/nodejs/node/pull/37215
     description: Runtime deprecation.
@@ -2720,9 +2723,9 @@ changes:
 
 Type: Runtime
 
-Using a trailing `"/"` to define
-[subpath folder mappings][] in the [subpath exports][] or
-[subpath imports][] fields is deprecated. Use [subpath patterns][] instead.
+Using a trailing `"/"` to define subpath folder mappings in the
+[subpath exports][] or [subpath imports][] fields is deprecated. Use
+[subpath patterns][] instead.
 
 ### DEP0149: `http.IncomingMessage#connection`
 <!-- YAML
@@ -2965,6 +2968,5 @@ for package `"exports"` and `"imports"` pattern resolutions.
 [legacy `urlObject`]: url.md#legacy-urlobject
 [static methods of `crypto.Certificate()`]: crypto.md#class-certificate
 [subpath exports]: packages.md#subpath-exports
-[subpath folder mappings]: packages.md#subpath-folder-mappings
 [subpath imports]: packages.md#subpath-imports
 [subpath patterns]: packages.md#subpath-patterns

doc/api/esm.md

@@ -1068,9 +1068,8 @@ The resolver can throw the following errors:
 >    1. Set _resolved_ to the URL resolution of _specifier_ relative to
 >       _parentURL_.
 > 1. Otherwise, if _specifier_ starts with _"#"_, then
->    1. Set _resolved_ to the destructured value of the result of
->       **PACKAGE_IMPORTS_RESOLVE**(_specifier_, _parentURL_,
->       _defaultConditions_).
+>    1. Set _resolved_ to the result of **PACKAGE_IMPORTS_RESOLVE**(_specifier_,
+>       _parentURL_, _defaultConditions_).
 > 1. Otherwise,
 >    1. Note: _specifier_ is now a bare specifier.
 >    1. Set _resolved_ the result of
@@ -1103,7 +1102,7 @@ The resolver can throw the following errors:
 > 1. If _packageName_ starts with _"."_ or contains _"\\"_ or _"%"_, then
 >    1. Throw an _Invalid Module Specifier_ error.
 > 1. Let _packageSubpath_ be _"."_ concatenated with the substring of
->       _packageSpecifier_ from the position at the length of _packageName_.
+>    _packageSpecifier_ from the position at the length of _packageName_.
 > 1. Let _selfUrl_ be the result of
 >    **PACKAGE_SELF_RESOLVE**(_packageName_, _packageSubpath_, _parentURL_).
 > 1. If _selfUrl_ is not **undefined**, return _selfUrl_.
@@ -1121,11 +1120,10 @@ The resolver can throw the following errors:
 >    1. If _pjson_ is not **null** and _pjson_._exports_ is not **null** or
 >       **undefined**, then
 >       1. Let _exports_ be _pjson.exports_.
->       1. Return the _resolved_ destructured value of the result of
->          **PACKAGE_EXPORTS_RESOLVE**(_packageURL_, _packageSubpath_,
->           _pjson.exports_, _defaultConditions_).
+>       1. Return the result of **PACKAGE_EXPORTS_RESOLVE**(_packageURL_,
+>          _packageSubpath_, _pjson.exports_, _defaultConditions_).
 >    1. Otherwise, if _packageSubpath_ is equal to _"."_, then
->       1. Return the result applying the legacy **LOAD_AS_DIRECTORY**
+>       1. Return the result of applying the legacy **LOAD_AS_DIRECTORY**
 >          CommonJS resolver to _packageURL_, throwing a _Module Not Found_
 >          error for no resolution.
 >    1. Otherwise,
@@ -1142,13 +1140,14 @@ The resolver can throw the following errors:
 >    **undefined**, then
 >    1. Return **undefined**.
 > 1. If _pjson.name_ is equal to _packageName_, then
->    1. Return the _resolved_ destructured value of the result of
->       **PACKAGE_EXPORTS_RESOLVE**(_packageURL_, _subpath_, _pjson.exports_,
->       _defaultConditions_).
+>    1. Return the result of **PACKAGE_EXPORTS_RESOLVE**(_packageURL_,
+>       _subpath_, _pjson.exports_, _defaultConditions_).
 > 1. Otherwise, return **undefined**.
 
 **PACKAGE_EXPORTS_RESOLVE**(_packageURL_, _subpath_, _exports_, _conditions_)
 
+> 1. If _subpath_ ends in _"/"_, then
+>    1. Throw an _Invalid Module Specifier_ error.
 > 1. If _exports_ is an Object with both a key starting with _"."_ and a key not
 >    starting with _"."_, throw an _Invalid Package Configuration_ error.
 > 1. If _subpath_ is equal to _"."_, then
@@ -1162,53 +1161,45 @@ The resolver can throw the following errors:
 >       1. Let _resolved_ be the result of **PACKAGE_TARGET_RESOLVE**(
 >          _packageURL_, _mainExport_, _""_, **false**, **false**,
 >          _conditions_).
->       1. If _resolved_ is not **null** or **undefined**, then
->          1. Return _resolved_.
+>       1. If _resolved_ is not **null** or **undefined**, return _resolved_.
 > 1. Otherwise, if _exports_ is an Object and all keys of _exports_ start with
 >    _"."_, then
 >    1. Let _matchKey_ be the string _"./"_ concatenated with _subpath_.
->    1. Let _resolvedMatch_ be result of **PACKAGE_IMPORTS_EXPORTS_RESOLVE**(
+>    1. Let _resolved_ be the result of **PACKAGE_IMPORTS_EXPORTS_RESOLVE**(
 >       _matchKey_, _exports_, _packageURL_, **false**, _conditions_).
->    1. If _resolvedMatch_._resolve_ is not **null** or **undefined**, then
->       1. Return _resolvedMatch_.
+>    1. If _resolved_ is not **null** or **undefined**, return _resolved_.
 > 1. Throw a _Package Path Not Exported_ error.
 
 **PACKAGE_IMPORTS_RESOLVE**(_specifier_, _parentURL_, _conditions_)
 
 > 1. Assert: _specifier_ begins with _"#"_.
-> 1. If _specifier_ is exactly equal to _"#"_ or starts with _"#/"_, then
+> 1. If _specifier_ is exactly equal to _"#"_, starts with _"#/"_, or ends in
+>    _"/"_, then
 >    1. Throw an _Invalid Module Specifier_ error.
 > 1. Let _packageURL_ be the result of **READ_PACKAGE_SCOPE**(_parentURL_).
 > 1. If _packageURL_ is not **null**, then
 >    1. Let _pjson_ be the result of **READ_PACKAGE_JSON**(_packageURL_).
 >    1. If _pjson.imports_ is a non-null Object, then
->       1. Let _resolvedMatch_ be the result of
->          **PACKAGE_IMPORTS_EXPORTS_RESOLVE**(_specifier_, _pjson.imports_,
->          _packageURL_, **true**, _conditions_).
->       1. If _resolvedMatch_._resolve_ is not **null** or **undefined**, then
->          1. Return _resolvedMatch_.
+>       1. Let _resolved_ be the result of **PACKAGE_IMPORTS_EXPORTS_RESOLVE**(
+>          _specifier_, _pjson.imports_, _packageURL_, **true**, _conditions_).
+>       1. If _resolved_ is not **null** or **undefined**, return _resolved_.
 > 1. Throw a _Package Import Not Defined_ error.
 
 **PACKAGE_IMPORTS_EXPORTS_RESOLVE**(_matchKey_, _matchObj_, _packageURL_,
 _isImports_, _conditions_)
 
-> 1. If _matchKey_ is a key of _matchObj_ and does not end in _"/"_ or contain
->    _"*"_, then
+> 1. Assert: _matchKey_ does not end in _"/"_.
+> 1. If _matchKey_ is a key of _matchObj_ and does not contain _"*"_, then
 >    1. Let _target_ be the value of _matchObj_\[_matchKey_\].
->    1. Let _resolved_ be the result of **PACKAGE_TARGET_RESOLVE**(
->       _packageURL_, _target_, _""_, **false**, _isImports_, _conditions_).
->    1. Return the object _{ resolved, exact: **true** }_.
-> 1. Let _expansionKeys_ be the list of keys of _matchObj_ either ending in
->    _"/"_ or containing only a single _"*"_, sorted by the sorting function
->    **PATTERN_KEY_COMPARE** which orders in descending order of specificity.
+>    1. Return the result of **PACKAGE_TARGET_RESOLVE**(_packageURL_, _target_,
+>       _""_, **false**, _isImports_, _conditions_).
+> 1. Let _expansionKeys_ be the list of keys of _matchObj_ containing only a
+>    single _"*"_, sorted by the sorting function **PATTERN_KEY_COMPARE** which
+>    orders in descending order of specificity.
 > 1. For each key _expansionKey_ in _expansionKeys_, do
->    1. Let _patternBase_ be **null**.
->    1. If _expansionKey_ contains _"*"_, set _patternBase_ to the substring of
->       _expansionKey_ up to but excluding the first _"*"_ character.
->    1. If _patternBase_ is not **null** and _matchKey_ starts with but is not
->       equal to _patternBase_, then
->       1. If _matchKey_ ends with _"/"_, throw an _Invalid Module Specifier_
->          error.
+>    1. Let _patternBase_ be the substring of _expansionKey_ up to but excluding
+>       the first _"*"_ character.
+>    1. 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.
 >       1. If _patternTrailer_ has zero length, or if _matchKey_ ends with
@@ -1218,20 +1209,9 @@ _isImports_, _conditions_)
 >          1. Let _subpath_ 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_.
->          1. Let _resolved_ be the result of **PACKAGE_TARGET_RESOLVE**(
->             _packageURL_, _target_, _subpath_, **true**, _isImports_,
->             _conditions_).
->          1. Return the object _{ resolved, exact: **true** }_.
->    1. Otherwise if _patternBase_ is **null** and _matchKey_ starts with
->       _expansionKey_, then
->       1. Let _target_ be the value of _matchObj_\[_expansionKey_\].
->       1. Let _subpath_ be the substring of _matchKey_ starting at the
->          index of the length of _expansionKey_.
->       1. Let _resolved_ be the result of **PACKAGE_TARGET_RESOLVE**(
->          _packageURL_, _target_, _subpath_, **false**, _isImports_,
->          _conditions_).
->       1. Return the object _{ resolved, exact: **false** }_.
-> 1. Return the object _{ resolved: **null**, exact: **true** }_.
+>          1. Return the result of **PACKAGE_TARGET_RESOLVE**(_packageURL_,
+>             _target_, _subpath_, **true**, _isImports_, _conditions_).
+> 1. Return **null**.
 
 **PATTERN_KEY_COMPARE**(_keyA_, _keyB_)
 

doc/api/packages.md

@@ -422,50 +422,6 @@ import featureX from 'es-module-package/features/x';
 // Loads ./node_modules/es-module-package/src/features/x.js
 ```
 
-### Subpath folder mappings
-<!-- YAML
-changes:
-  - version: v16.0.0
-    pr-url: https://github.com/nodejs/node/pull/37215
-    description: Runtime deprecation.
-  - version: v15.1.0
-    pr-url: https://github.com/nodejs/node/pull/35747
-    description: Runtime deprecation for self-referencing imports.
-  - version:
-    - v14.13.0
-    - v12.20.0
-    pr-url: https://github.com/nodejs/node/pull/34718
-    description: Documentation-only deprecation.
--->
-
-> Stability: 0 - Deprecated: Use subpath patterns instead.
-
-Before subpath patterns were supported, a trailing `"/"` suffix was used to
-support folder mappings:
-
-```json
-{
-  "exports": {
-    "./features/": "./features/"
-  }
-}
-```
-
-_This feature will be removed in a future release._
-
-Instead, use direct [subpath patterns][]:
-
-```json
-{
-  "exports": {
-    "./features/*": "./features/*.js"
-  }
-}
-```
-
-The benefit of patterns over folder exports is that packages can always be
-imported by consumers without subpath file extensions being necessary.
-
 ### Exports sugar
 <!-- YAML
 added: v12.11.0
@@ -1270,7 +1226,6 @@ This field defines [subpath imports][] for the current package.
 [self-reference]: #self-referencing-a-package-using-its-name
 [subpath exports]: #subpath-exports
 [subpath imports]: #subpath-imports
-[subpath patterns]: #subpath-patterns
 [supported package managers]: corepack.md#supported-package-managers
 [the dual CommonJS/ES module packages section]: #dual-commonjses-module-packages
 [the full specifier path]: esm.md#mandatory-file-extensions

lib/internal/modules/cjs/loader.js

@@ -457,7 +457,7 @@ function trySelf(parentPath, request) {
   try {
     return finalizeEsmResolution(packageExportsResolve(
       pathToFileURL(pkgPath + '/package.json'), expansion, pkg,
-      pathToFileURL(parentPath), cjsConditions), request, parentPath, pkgPath);
+      pathToFileURL(parentPath), cjsConditions), parentPath, pkgPath);
   } catch (e) {
     if (e.code === 'ERR_MODULE_NOT_FOUND')
       throw createEsmNotFoundErr(request, pkgPath + '/package.json');
@@ -481,7 +481,7 @@ function resolveExports(nmPath, request) {
     try {
       return finalizeEsmResolution(packageExportsResolve(
         pathToFileURL(pkgPath + '/package.json'), '.' + expansion, pkg, null,
-        cjsConditions), request, null, pkgPath);
+        cjsConditions), null, pkgPath);
     } catch (e) {
       if (e.code === 'ERR_MODULE_NOT_FOUND')
         throw createEsmNotFoundErr(request, pkgPath + '/package.json');
@@ -894,7 +894,7 @@ Module._resolveFilename = function(request, parent, isMain, options) {
         try {
           return finalizeEsmResolution(
             packageImportsResolve(request, pathToFileURL(parent.filename),
-                                  cjsConditions), request, parent.filename,
+                                  cjsConditions), parent.filename,
             pkg.path);
         } catch (e) {
           if (e.code === 'ERR_MODULE_NOT_FOUND')
@@ -936,18 +936,12 @@ Module._resolveFilename = function(request, parent, isMain, options) {
   throw err;
 };
 
-function finalizeEsmResolution(match, request, parentPath, pkgPath) {
-  const { resolved, exact } = match;
+function finalizeEsmResolution(resolved, parentPath, pkgPath) {
   if (RegExpPrototypeTest(encodedSepRegEx, resolved))
     throw new ERR_INVALID_MODULE_SPECIFIER(
       resolved, 'must not include encoded "/" or "\\" characters', parentPath);
   const filename = fileURLToPath(resolved);
-  let actual = tryFile(filename);
-  if (!exact && !actual) {
-    const exts = ObjectKeys(Module._extensions);
-    actual = tryExtensions(filename, exts, false) ||
-      tryPackage(filename, exts, false, request);
-  }
+  const actual = tryFile(filename);
   if (actual)
     return actual;
   const err = createEsmNotFoundErr(filename,