Refactor module resolution Extensions, fix lookup priorities

src/compiler/diagnosticMessages.json

@@ -4547,7 +4547,7 @@
         "category": "Message",
         "code": 6094
     },
-    "Loading module as file / folder, candidate module location '{0}', target file type '{1}'.": {
+    "Loading module as file / folder, candidate module location '{0}', target file types: {1}.": {
         "category": "Message",
         "code": 6095
     },
@@ -4559,7 +4559,7 @@
         "category": "Message",
         "code": 6097
     },
-    "Loading module '{0}' from 'node_modules' folder, target file type '{1}'.": {
+    "Loading module '{0}' from 'node_modules' folder, target file types: {1}.": {
         "category": "Message",
         "code": 6098
     },

src/compiler/utilities.ts

@@ -7776,6 +7776,8 @@ const allSupportedExtensions: readonly Extension[][] = [[Extension.Ts, Extension
 const allSupportedExtensionsWithJson: readonly Extension[][] = [...allSupportedExtensions, [Extension.Json]];
 /** @internal */
 export const supportedDeclarationExtensions: readonly Extension[] = [Extension.Dts, Extension.Dcts, Extension.Dmts];
+/** @internal */
+export const supportedTSImplementationExtensions: readonly Extension[] = [Extension.Ts, Extension.Cts, Extension.Mts, Extension.Tsx];
 
 /** @internal */
 export function getSupportedExtensions(options?: CompilerOptions): readonly Extension[][];

src/testRunner/unittests/reuseProgramStructure.ts

@@ -274,7 +274,7 @@ describe("unittests:: Reuse program structure:: General", () => {
                 [
                     "======== Resolving module 'a' from 'file1.ts'. ========",
                     "Explicitly specified module resolution kind: 'NodeJs'.",
-                    "Loading module 'a' from 'node_modules' folder, target file type 'TypeScript'.",
+                    "Loading module 'a' from 'node_modules' folder, target file types: TypeScript, Declaration.",
                     "File 'node_modules/a/package.json' does not exist.",
                     "File 'node_modules/a.ts' does not exist.",
                     "File 'node_modules/a.tsx' does not exist.",
@@ -285,7 +285,7 @@ describe("unittests:: Reuse program structure:: General", () => {
                     "File 'node_modules/@types/a/package.json' does not exist.",
                     "File 'node_modules/@types/a.d.ts' does not exist.",
                     "File 'node_modules/@types/a/index.d.ts' does not exist.",
-                    "Loading module 'a' from 'node_modules' folder, target file type 'JavaScript'.",
+                    "Loading module 'a' from 'node_modules' folder, target file types: JavaScript.",
                     "File 'node_modules/a/package.json' does not exist according to earlier cached lookups.",
                     "File 'node_modules/a.js' does not exist.",
                     "File 'node_modules/a.jsx' does not exist.",
@@ -307,7 +307,7 @@ describe("unittests:: Reuse program structure:: General", () => {
                 [
                     "======== Resolving module 'a' from 'file1.ts'. ========",
                     "Explicitly specified module resolution kind: 'NodeJs'.",
-                    "Loading module 'a' from 'node_modules' folder, target file type 'TypeScript'.",
+                    "Loading module 'a' from 'node_modules' folder, target file types: TypeScript, Declaration.",
                     "File 'node_modules/a/package.json' does not exist.",
                     "File 'node_modules/a.ts' does not exist.",
                     "File 'node_modules/a.tsx' does not exist.",

tests/baselines/reference/cachedModuleResolution1.trace.json

@@ -1,7 +1,7 @@
 [
     "======== Resolving module 'foo' from '/a/b/c/d/e/app.ts'. ========",
     "Explicitly specified module resolution kind: 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Directory '/a/b/c/d/e/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/c/d/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/c/node_modules' does not exist, skipping all lookups in it.",
@@ -12,7 +12,7 @@
     "======== Module name 'foo' was successfully resolved to '/a/b/node_modules/foo.d.ts'. ========",
     "======== Resolving module 'foo' from '/a/b/c/lib.ts'. ========",
     "Explicitly specified module resolution kind: 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Resolution for module 'foo' was found in cache from location '/a/b/c'.",
     "======== Module name 'foo' was successfully resolved to '/a/b/node_modules/foo.d.ts'. ========"
 ]

tests/baselines/reference/cachedModuleResolution2.trace.json

@@ -1,7 +1,7 @@
 [
     "======== Resolving module 'foo' from '/a/b/c/lib.ts'. ========",
     "Explicitly specified module resolution kind: 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Directory '/a/b/c/node_modules' does not exist, skipping all lookups in it.",
     "File '/a/b/node_modules/foo.ts' does not exist.",
     "File '/a/b/node_modules/foo.tsx' does not exist.",
@@ -10,7 +10,7 @@
     "======== Module name 'foo' was successfully resolved to '/a/b/node_modules/foo.d.ts'. ========",
     "======== Resolving module 'foo' from '/a/b/c/d/e/app.ts'. ========",
     "Explicitly specified module resolution kind: 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Directory '/a/b/c/d/e/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/c/d/node_modules' does not exist, skipping all lookups in it.",
     "Resolution for module 'foo' was found in cache from location '/a/b/c'.",

tests/baselines/reference/cachedModuleResolution5.trace.json

@@ -1,7 +1,7 @@
 [
     "======== Resolving module 'foo' from '/a/b/c/d/e/app.ts'. ========",
     "Explicitly specified module resolution kind: 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Directory '/a/b/c/d/e/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/c/d/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/c/node_modules' does not exist, skipping all lookups in it.",
@@ -12,7 +12,7 @@
     "======== Module name 'foo' was successfully resolved to '/a/b/node_modules/foo.d.ts'. ========",
     "======== Resolving module 'foo' from '/a/b/lib.ts'. ========",
     "Explicitly specified module resolution kind: 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Resolution for module 'foo' was found in cache from location '/a/b'.",
     "======== Module name 'foo' was successfully resolved to '/a/b/node_modules/foo.d.ts'. ========"
 ]

tests/baselines/reference/cachedModuleResolution6.trace.json

@@ -1,14 +1,14 @@
 [
     "======== Resolving module 'foo' from '/a/b/c/d/e/app.ts'. ========",
     "Explicitly specified module resolution kind: 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Directory '/a/b/c/d/e/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/c/d/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/c/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/node_modules' does not exist, skipping all lookups in it.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'JavaScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: JavaScript.",
     "Directory '/a/b/c/d/e/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/c/d/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/c/node_modules' does not exist, skipping all lookups in it.",
@@ -18,7 +18,7 @@
     "======== Module name 'foo' was not resolved. ========",
     "======== Resolving module 'foo' from '/a/b/c/lib.ts'. ========",
     "Explicitly specified module resolution kind: 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Resolution for module 'foo' was found in cache from location '/a/b/c'.",
     "======== Module name 'foo' was not resolved. ========"
 ]

tests/baselines/reference/cachedModuleResolution7.trace.json

@@ -1,20 +1,20 @@
 [
     "======== Resolving module 'foo' from '/a/b/c/lib.ts'. ========",
     "Explicitly specified module resolution kind: 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Directory '/a/b/c/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/node_modules' does not exist, skipping all lookups in it.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'JavaScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: JavaScript.",
     "Directory '/a/b/c/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/node_modules' does not exist, skipping all lookups in it.",
     "======== Module name 'foo' was not resolved. ========",
     "======== Resolving module 'foo' from '/a/b/c/d/e/app.ts'. ========",
     "Explicitly specified module resolution kind: 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Directory '/a/b/c/d/e/node_modules' does not exist, skipping all lookups in it.",
     "Directory '/a/b/c/d/node_modules' does not exist, skipping all lookups in it.",
     "Resolution for module 'foo' was found in cache from location '/a/b/c'.",

tests/baselines/reference/duplicatePackage_relativeImportWithinPackage.trace.json

@@ -1,7 +1,7 @@
 [
     "======== Resolving module 'foo/use' from '/index.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
-    "Loading module 'foo/use' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo/use' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Found 'package.json' at '/node_modules/foo/package.json'.",
     "'package.json' does not have a 'typesVersions' field.",
     "File '/node_modules/foo/use.ts' does not exist.",
@@ -11,7 +11,7 @@
     "======== Module name 'foo/use' was successfully resolved to '/node_modules/foo/use.d.ts' with Package ID 'foo/use.d.ts@1.2.3'. ========",
     "======== Resolving module 'a' from '/index.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
-    "Loading module 'a' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'a' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "File '/node_modules/a/package.json' does not exist.",
     "File '/node_modules/a.ts' does not exist.",
     "File '/node_modules/a.tsx' does not exist.",
@@ -23,15 +23,15 @@
     "======== Module name 'a' was successfully resolved to '/node_modules/a/index.d.ts'. ========",
     "======== Resolving module './index' from '/node_modules/foo/use.d.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
-    "Loading module as file / folder, candidate module location '/node_modules/foo/index', target file type 'TypeScript'.",
+    "Loading module as file / folder, candidate module location '/node_modules/foo/index', target file types: TypeScript, Declaration.",
     "File '/node_modules/foo/index.ts' does not exist.",
     "File '/node_modules/foo/index.tsx' does not exist.",
     "File '/node_modules/foo/index.d.ts' exist - use it as a name resolution result.",
     "File '/node_modules/foo/package.json' exists according to earlier cached lookups.",
     "======== Module name './index' was successfully resolved to '/node_modules/foo/index.d.ts' with Package ID 'foo/index.d.ts@1.2.3'. ========",
     "======== Resolving module 'foo' from '/node_modules/a/index.d.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
-    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'foo' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Found 'package.json' at '/node_modules/a/node_modules/foo/package.json'.",
     "'package.json' does not have a 'typesVersions' field.",
     "File '/node_modules/a/node_modules/foo.ts' does not exist.",

tests/baselines/reference/duplicatePackage_relativeImportWithinPackage_scoped.trace.json

@@ -1,7 +1,7 @@
 [
     "======== Resolving module '@foo/bar/use' from '/index.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
-    "Loading module '@foo/bar/use' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module '@foo/bar/use' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Found 'package.json' at '/node_modules/@foo/bar/package.json'.",
     "'package.json' does not have a 'typesVersions' field.",
     "File '/node_modules/@foo/bar/use.ts' does not exist.",
@@ -11,7 +11,7 @@
     "======== Module name '@foo/bar/use' was successfully resolved to '/node_modules/@foo/bar/use.d.ts' with Package ID '@foo/bar/use.d.ts@1.2.3'. ========",
     "======== Resolving module 'a' from '/index.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
-    "Loading module 'a' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module 'a' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "File '/node_modules/a/package.json' does not exist.",
     "File '/node_modules/a.ts' does not exist.",
     "File '/node_modules/a.tsx' does not exist.",
@@ -23,15 +23,15 @@
     "======== Module name 'a' was successfully resolved to '/node_modules/a/index.d.ts'. ========",
     "======== Resolving module './index' from '/node_modules/@foo/bar/use.d.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
-    "Loading module as file / folder, candidate module location '/node_modules/@foo/bar/index', target file type 'TypeScript'.",
+    "Loading module as file / folder, candidate module location '/node_modules/@foo/bar/index', target file types: TypeScript, Declaration.",
     "File '/node_modules/@foo/bar/index.ts' does not exist.",
     "File '/node_modules/@foo/bar/index.tsx' does not exist.",
     "File '/node_modules/@foo/bar/index.d.ts' exist - use it as a name resolution result.",
     "File '/node_modules/@foo/bar/package.json' exists according to earlier cached lookups.",
     "======== Module name './index' was successfully resolved to '/node_modules/@foo/bar/index.d.ts' with Package ID '@foo/bar/index.d.ts@1.2.3'. ========",
     "======== Resolving module '@foo/bar' from '/node_modules/a/index.d.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
-    "Loading module '@foo/bar' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Loading module '@foo/bar' from 'node_modules' folder, target file types: TypeScript, Declaration.",
     "Found 'package.json' at '/node_modules/a/node_modules/@foo/bar/package.json'.",
     "'package.json' does not have a 'typesVersions' field.",
     "File '/node_modules/a/node_modules/@foo/bar.ts' does not exist.",

tests/baselines/reference/extensionLoadingPriority(moduleresolution=classic).symbols

@@ -0,0 +1,23 @@
+=== /project/a.js ===
+
+export default "a.js";
+
+=== /project/a.js.js ===
+
+export default "a.js.js";
+
+=== /project/dir/index.ts ===
+
+export default "dir/index.ts";
+
+=== /project/dir.js ===
+
+export default "dir.js";
+
+=== /project/b.ts ===
+import a from "./a.js";
+>a : Symbol(a, Decl(b.ts, 0, 6))
+
+import dir from "./dir";
+>dir : Symbol(dir, Decl(b.ts, 1, 6))
+

tests/baselines/reference/extensionLoadingPriority(moduleresolution=classic).types

@@ -0,0 +1,23 @@
+=== /project/a.js ===
+
+export default "a.js";
+
+=== /project/a.js.js ===
+
+export default "a.js.js";
+
+=== /project/dir/index.ts ===
+
+export default "dir/index.ts";
+
+=== /project/dir.js ===
+
+export default "dir.js";
+
+=== /project/b.ts ===
+import a from "./a.js";
+>a : "a.js"
+
+import dir from "./dir";
+>dir : "dir.js"
+

tests/baselines/reference/extensionLoadingPriority(moduleresolution=node).symbols

@@ -0,0 +1,23 @@
+=== /project/a.js ===
+
+export default "a.js";
+
+=== /project/a.js.js ===
+
+export default "a.js.js";
+
+=== /project/dir/index.ts ===
+
+export default "dir/index.ts";
+
+=== /project/dir.js ===
+
+export default "dir.js";
+
+=== /project/b.ts ===
+import a from "./a.js";
+>a : Symbol(a, Decl(b.ts, 0, 6))
+
+import dir from "./dir";
+>dir : Symbol(dir, Decl(b.ts, 1, 6))
+

tests/baselines/reference/extensionLoadingPriority(moduleresolution=node).types

@@ -0,0 +1,23 @@
+=== /project/a.js ===
+
+export default "a.js";
+
+=== /project/a.js.js ===
+
+export default "a.js.js";
+
+=== /project/dir/index.ts ===
+
+export default "dir/index.ts";
+
+=== /project/dir.js ===
+
+export default "dir.js";
+
+=== /project/b.ts ===
+import a from "./a.js";
+>a : "a.js"
+
+import dir from "./dir";
+>dir : "dir/index.ts"
+

tests/baselines/reference/extensionLoadingPriority(moduleresolution=node16).symbols

@@ -0,0 +1,23 @@
+=== /project/a.js ===
+
+export default "a.js";
+
+=== /project/a.js.js ===
+
+export default "a.js.js";
+
+=== /project/dir/index.ts ===
+
+export default "dir/index.ts";
+
+=== /project/dir.js ===
+
+export default "dir.js";
+
+=== /project/b.ts ===
+import a from "./a.js";
+>a : Symbol(a, Decl(b.ts, 0, 6))
+
+import dir from "./dir";
+>dir : Symbol(dir, Decl(b.ts, 1, 6))
+

tests/baselines/reference/extensionLoadingPriority(moduleresolution=node16).types

@@ -0,0 +1,23 @@
+=== /project/a.js ===
+
+export default "a.js";
+
+=== /project/a.js.js ===
+
+export default "a.js.js";
+
+=== /project/dir/index.ts ===
+
+export default "dir/index.ts";
+
+=== /project/dir.js ===
+
+export default "dir.js";
+
+=== /project/b.ts ===
+import a from "./a.js";
+>a : "a.js"
+
+import dir from "./dir";
+>dir : "dir.js"
+