module: support pattern trailers

PR-URL: https://github.com/nodejs/node/pull/39635
Reviewed-By: Bradley Farias <bradley.meck@gmail.com>

2 files changed, 43 insertions, 17 deletions

diff --git a/doc/api/esm.md b/doc/api/esm.md
index a5ad877d9e0..dc93e659b01 100644
--- a/doc/api/esm.md
+++ b/doc/api/esm.md
@@ -1176,25 +1176,36 @@ The resolver can throw the following errors:
 **PACKAGE_IMPORTS_EXPORTS_RESOLVE**(_matchKey_, _matchObj_, _packageURL_,
 _isImports_, _conditions_)
 
-> 1. If _matchKey_ is a key of _matchObj_, and does not end in _"*"_, then
+> 1. If _matchKey_ is a key of _matchObj_ and does not end in _"/"_ or 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_ ending in _"/"_
->    or _"*"_, sorted by length descending.
+> 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. For each key _expansionKey_ in _expansionKeys_, do
->    1. If _expansionKey_ ends in _"*"_ and _matchKey_ starts with but is
->       not equal to the substring of _expansionKey_ excluding the last _"*"_
->       character, 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_ minus one.
->       1. Let _resolved_ be the result of **PACKAGE_TARGET_RESOLVE**(
->          _packageURL_, _target_, _subpath_, **true**, _isImports_,
->          _conditions_).
->       1. Return the object _{ resolved, exact: **true** }_.
->    1. If _matchKey_ starts with _expansionKey_, then
+>    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. 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
+>          _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_\[_expansionKey_\].
+>          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_.
@@ -1204,6 +1215,22 @@ _isImports_, _conditions_)
 >       1. Return the object _{ resolved, exact: **false** }_.
 > 1. Return the object _{ resolved: **null**, exact: **true** }_.
 
+**PATTERN_KEY_COMPARE**(_keyA_, _keyB_)
+
+> 1. Assert: _keyA_ ends with _"/"_ or contains only a single _"*"_.
+> 1. Assert: _keyB_ ends with _"/"_ or contains only a single _"*"_.
+> 1. Let _baseLengthA_ be the index of _"*"_ in _keyA_ plus one, if _keyA_
+>    contains _"*"_, or the length of _keyA_ otherwise.
+> 1. Let _baseLengthB_ be the index of _"*"_ in _keyB_ plus one, if _keyB_
+>    contains _"*"_, or the length of _keyB_ otherwise.
+> 1. If _baseLengthA_ is greater than _baseLengthB_, return -1.
+> 1. If _baseLengthB_ is greater than _baseLengthA_, return 1.
+> 1. If _keyA_ does not contain _"*"_, return 1.
+> 1. If _keyB_ does not contain _"*"_, return -1.
+> 1. If the length of _keyA_ is greater than the length of _keyB_, return -1.
+> 1. If the length of _keyB_ is greater than the length of _keyA_, return 1.
+> 1. Return 0.
+
 **PACKAGE_TARGET_RESOLVE**(_packageURL_, _target_, _subpath_, _pattern_,
 _internal_, _conditions_)
 
diff --git a/doc/api/packages.md b/doc/api/packages.md
index 09acf5a5490..8817350b646 100644
--- a/doc/api/packages.md
+++ b/doc/api/packages.md
@@ -376,9 +376,8 @@ For these use cases, subpath export patterns can be used instead:
 **`*` maps expose nested subpaths as it is a string replacement syntax
 only.**
 
-The left hand matching pattern must always end in `*`. All instances of `*` on
-the right hand side will then be replaced with this value, including if it
-contains any `/` separators.
+All instances of `*` on the right hand side will then be replaced with this
+value, including if it contains any `/` separators.
 
 ```js
 import featureX from 'es-module-package/features/x';