From decc3cd671125acc66e1a2fd3941167985e5c145 Mon Sep 17 00:00:00 2001
From: Ron Buckton <ron.buckton@microsoft.com>
Date: Mon, 12 Aug 2019 16:05:15 -0700
Subject: [PATCH] Elide /index from auto-import when using rootDirs compiler
 option (#32828)

---
 src/compiler/moduleSpecifiers.ts              |  8 ++++---
 .../importNameCodeFixNewImportRootDirs1.ts    | 22 +++++++++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)
 create mode 100644 tests/cases/fourslash/importNameCodeFixNewImportRootDirs1.ts

diff --git a/src/compiler/moduleSpecifiers.ts b/src/compiler/moduleSpecifiers.ts
index fbed429e312..8c96199b7bf 100644
--- a/src/compiler/moduleSpecifiers.ts
+++ b/src/compiler/moduleSpecifiers.ts
@@ -114,7 +114,7 @@ namespace ts.moduleSpecifiers {
     function getLocalModuleSpecifier(moduleFileName: string, { getCanonicalFileName, sourceDirectory }: Info, compilerOptions: CompilerOptions, { ending, relativePreference }: Preferences): string {
         const { baseUrl, paths, rootDirs } = compilerOptions;
 
-        const relativePath = rootDirs && tryGetModuleNameFromRootDirs(rootDirs, moduleFileName, sourceDirectory, getCanonicalFileName) ||
+        const relativePath = rootDirs && tryGetModuleNameFromRootDirs(rootDirs, moduleFileName, sourceDirectory, getCanonicalFileName, ending, compilerOptions) ||
             removeExtensionAndIndexPostFix(ensurePathIsNonModuleName(getRelativePathFromDirectory(sourceDirectory, moduleFileName, getCanonicalFileName)), ending, compilerOptions);
         if (!baseUrl || relativePreference === RelativePreference.Relative) {
             return relativePath;
@@ -248,7 +248,7 @@ namespace ts.moduleSpecifiers {
         }
     }
 
-    function tryGetModuleNameFromRootDirs(rootDirs: ReadonlyArray<string>, moduleFileName: string, sourceDirectory: string, getCanonicalFileName: (file: string) => string): string | undefined {
+    function tryGetModuleNameFromRootDirs(rootDirs: ReadonlyArray<string>, moduleFileName: string, sourceDirectory: string, getCanonicalFileName: (file: string) => string, ending: Ending, compilerOptions: CompilerOptions): string | undefined {
         const normalizedTargetPath = getPathRelativeToRootDirs(moduleFileName, rootDirs, getCanonicalFileName);
         if (normalizedTargetPath === undefined) {
             return undefined;
@@ -256,7 +256,9 @@ namespace ts.moduleSpecifiers {
 
         const normalizedSourcePath = getPathRelativeToRootDirs(sourceDirectory, rootDirs, getCanonicalFileName);
         const relativePath = normalizedSourcePath !== undefined ? ensurePathIsNonModuleName(getRelativePathFromDirectory(normalizedSourcePath, normalizedTargetPath, getCanonicalFileName)) : normalizedTargetPath;
-        return removeFileExtension(relativePath);
+        return getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.NodeJs
+            ? removeExtensionAndIndexPostFix(relativePath, ending, compilerOptions)
+            : removeFileExtension(relativePath);
     }
 
     function tryGetModuleNameAsNodeModule(moduleFileName: string, { getCanonicalFileName, sourceDirectory }: Info, host: ModuleSpecifierResolutionHost, options: CompilerOptions): string | undefined {
diff --git a/tests/cases/fourslash/importNameCodeFixNewImportRootDirs1.ts b/tests/cases/fourslash/importNameCodeFixNewImportRootDirs1.ts
new file mode 100644
index 00000000000..dfac047ae19
--- /dev/null
+++ b/tests/cases/fourslash/importNameCodeFixNewImportRootDirs1.ts
@@ -0,0 +1,22 @@
+/// <reference path="fourslash.ts" />
+
+// @Filename: a/f1.ts
+//// [|foo/*0*/();|]
+
+// @Filename: a/b/index.ts
+//// export function foo() {};
+
+// @Filename: tsconfig.json
+//// {
+////     "compilerOptions": {
+////         "rootDirs": [
+////             "a"
+////         ]
+////     }
+//// }
+
+verify.importFixAtPosition([
+`import { foo } from "./b";
+
+foo();`
+]);