From 0d6c2cbafc53fee960e34e2c7ccc1494b9d1ba96 Mon Sep 17 00:00:00 2001
From: Guy Bedford <guybedford@gmail.com>
Date: Wed, 8 Sep 2021 12:14:03 -0700
Subject: [PATCH] module: support pattern trailers for imports field

---
 lib/internal/modules/esm/resolve.js           | 38 ++++++++++++-------
 test/es-module/test-esm-imports.mjs           |  2 +
 .../es-modules/pkgimports/package.json        |  1 +
 3 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/lib/internal/modules/esm/resolve.js b/lib/internal/modules/esm/resolve.js
index ca0e1b316fc5b6..0ea5630d7a9c34 100644
--- a/lib/internal/modules/esm/resolve.js
+++ b/lib/internal/modules/esm/resolve.js
@@ -22,7 +22,6 @@ const {
   StringPrototypeSlice,
   StringPrototypeSplit,
   StringPrototypeStartsWith,
-  StringPrototypeSubstr,
 } = primordials;
 const internalFS = require('internal/fs/utils');
 const { NativeModule } = require('internal/bootstrap/loaders');
@@ -695,7 +694,9 @@ function packageImportsResolve(name, base, conditions) {
     packageJSONUrl = pathToFileURL(packageConfig.pjsonPath);
     const imports = packageConfig.imports;
     if (imports) {
-      if (ObjectPrototypeHasOwnProperty(imports, name)) {
+      if (ObjectPrototypeHasOwnProperty(imports, name) &&
+          !StringPrototypeIncludes(name, '*') &&
+          !StringPrototypeEndsWith(name, '/')) {
         const resolved = resolvePackageTarget(
           packageJSONUrl, imports[name], '', name, base, false, true, conditions
         );
@@ -703,30 +704,39 @@ function packageImportsResolve(name, base, conditions) {
           return { resolved, exact: true };
       } else {
         let bestMatch = '';
+        let bestMatchSubpath;
         const keys = ObjectGetOwnPropertyNames(imports);
         for (let i = 0; i < keys.length; i++) {
           const key = keys[i];
-          if (key[key.length - 1] === '*' &&
+          const patternIndex = StringPrototypeIndexOf(key, '*');
+          if (patternIndex !== -1 &&
               StringPrototypeStartsWith(name,
-                                        StringPrototypeSlice(key, 0, -1)) &&
-              name.length >= key.length &&
-              key.length > bestMatch.length) {
-            bestMatch = key;
+                                        StringPrototypeSlice(key, 0,
+                                                             patternIndex))) {
+            const patternTrailer = StringPrototypeSlice(key, patternIndex + 1);
+            if (name.length >= key.length &&
+                StringPrototypeEndsWith(name, patternTrailer) &&
+                patternKeyCompare(bestMatch, key) === 1 &&
+                StringPrototypeLastIndexOf(key, '*') === patternIndex) {
+              bestMatch = key;
+              bestMatchSubpath = StringPrototypeSlice(
+                name, patternIndex, name.length - patternTrailer.length);
+            }
           } else if (key[key.length - 1] === '/' &&
             StringPrototypeStartsWith(name, key) &&
-            key.length > bestMatch.length) {
+            patternKeyCompare(bestMatch, key) === 1) {
             bestMatch = key;
+            bestMatchSubpath = StringPrototypeSlice(name, key.length);
           }
         }
 
         if (bestMatch) {
           const target = imports[bestMatch];
-          const pattern = bestMatch[bestMatch.length - 1] === '*';
-          const subpath = StringPrototypeSubstr(name, bestMatch.length -
-            (pattern ? 1 : 0));
-          const resolved = resolvePackageTarget(
-            packageJSONUrl, target, subpath, bestMatch, base, pattern, true,
-            conditions);
+          const pattern = StringPrototypeIncludes(bestMatch, '*');
+          const resolved = resolvePackageTarget(packageJSONUrl, target,
+                                                bestMatchSubpath, bestMatch,
+                                                base, pattern, true,
+                                                conditions);
           if (resolved !== null) {
             if (!pattern)
               emitFolderMapDeprecation(bestMatch, packageJSONUrl, false, base);
diff --git a/test/es-module/test-esm-imports.mjs b/test/es-module/test-esm-imports.mjs
index 694496a2ff2c93..577e33b60d08ec 100644
--- a/test/es-module/test-esm-imports.mjs
+++ b/test/es-module/test-esm-imports.mjs
@@ -20,6 +20,8 @@ const { requireImport, importImport } = importer;
     ['#external', { default: 'asdf' }],
     // External subpath imports
     ['#external/subpath/asdf.js', { default: 'asdf' }],
+    // Trailing pattern imports
+    ['#subpath/asdf.asdf', { default: 'test' }],
   ]);
 
   for (const [validSpecifier, expected] of internalImports) {
diff --git a/test/fixtures/es-modules/pkgimports/package.json b/test/fixtures/es-modules/pkgimports/package.json
index a2224b39ddd2ac..299ce9c197b554 100644
--- a/test/fixtures/es-modules/pkgimports/package.json
+++ b/test/fixtures/es-modules/pkgimports/package.json
@@ -6,6 +6,7 @@
       "require": "./requirebranch.js"
     },
     "#subpath/*": "./sub/*",
+    "#subpath/*.asdf": "./test.js",
     "#external": "pkgexports/valid-cjs",
     "#external/subpath/*": "pkgexports/sub/*",
     "#external/invalidsubpath/": "pkgexports/sub",