From 3c5a6e1ae7848d97e7178a4d3e8043cf33d15fca Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Tue, 7 Nov 2017 13:08:20 -0800
Subject: [PATCH] Allow watch host to specify module name resolver

---
 src/compiler/watch.ts                         | 10 ++++++++--
 tests/baselines/reference/api/typescript.d.ts |  2 ++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/compiler/watch.ts b/src/compiler/watch.ts
index 0ff0d2f6122..ff352c0febc 100644
--- a/src/compiler/watch.ts
+++ b/src/compiler/watch.ts
@@ -170,6 +170,9 @@ namespace ts {
         beforeProgramCreate(compilerOptions: CompilerOptions): void;
         /** Custom action after new program creation is successful */
         afterProgramCreate(host: DirectoryStructureHost, program: Program): void;
+
+        /** Optional module name resolver */
+        moduleNameResolver?(moduleNames: string[], containingFile: string, reusedNames?: string[]): ResolvedModule[];
     }
 
     /**
@@ -308,6 +311,9 @@ namespace ts {
         const getCachedDirectoryStructureHost = configFileName && (() => directoryStructureHost as CachedDirectoryStructureHost);
         const getCanonicalFileName = createGetCanonicalFileName(system.useCaseSensitiveFileNames);
         let newLine = getNewLineCharacter(compilerOptions, system);
+        const resolveModuleNames: (moduleNames: string[], containingFile: string, reusedNames?: string[]) => ResolvedModule[] = host.moduleNameResolver ?
+            (moduleNames, containingFile, reusedNames) => host.moduleNameResolver(moduleNames, containingFile, reusedNames) :
+            (moduleNames, containingFile, reusedNames?) => resolutionCache.resolveModuleNames(moduleNames, containingFile, reusedNames, /*logChanges*/ false);
 
         const compilerHost: CompilerHost & ResolutionCacheHost = {
             // Members for CompilerHost
@@ -328,7 +334,7 @@ namespace ts {
             getDirectories: path => directoryStructureHost.getDirectories(path),
             realpath,
             resolveTypeReferenceDirectives: (typeDirectiveNames, containingFile) => resolutionCache.resolveTypeReferenceDirectives(typeDirectiveNames, containingFile),
-            resolveModuleNames: (moduleNames, containingFile, reusedNames?) => resolutionCache.resolveModuleNames(moduleNames, containingFile, reusedNames, /*logChanges*/ false),
+            resolveModuleNames,
             onReleaseOldSourceFile,
             // Members for ResolutionCacheHost
             toPath,
@@ -341,7 +347,7 @@ namespace ts {
                 hasChangedAutomaticTypeDirectiveNames = true;
                 scheduleProgramUpdate();
             },
-            writeLog
+            writeLog,
         };
         // Cache for the module resolution
         const resolutionCache = createResolutionCache(compilerHost, configFileName ?
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index fb5ee37012d..63e2d453b18 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -3825,6 +3825,8 @@ declare namespace ts {
         beforeProgramCreate(compilerOptions: CompilerOptions): void;
         /** Custom action after new program creation is successful */
         afterProgramCreate(host: DirectoryStructureHost, program: Program): void;
+        /** Optional module name resolver */
+        moduleNameResolver?(moduleNames: string[], containingFile: string, reusedNames?: string[]): ResolvedModule[];
     }
     /**
      * Host to create watch with root files and options