diff --git a/src/services/shims.ts b/src/services/shims.ts
index 4debcb23774..0aa411536f1 100644
--- a/src/services/shims.ts
+++ b/src/services/shims.ts
@@ -1060,8 +1060,15 @@ namespace ts {
             return this.forwardJSONCall(`resolveModuleName('${fileName}')`, () => {
                 const compilerOptions = <CompilerOptions>JSON.parse(compilerOptionsJson);
                 const result = resolveModuleName(moduleName, normalizeSlashes(fileName), compilerOptions, this.host);
+                const resolvedFileName = result.resolvedModule ? result.resolvedModule.resolvedFileName : undefined;
+                if (resolvedFileName && !compilerOptions.allowJs && fileExtensionIs(resolvedFileName, ".js")) {
+                    return {
+                        resolvedFileName: undefined,
+                        failedLookupLocations: undefined
+                    };
+                }
                 return {
-                    resolvedFileName: result.resolvedModule ? result.resolvedModule.resolvedFileName : undefined,
+                    resolvedFileName,
                     failedLookupLocations: result.failedLookupLocations
                 };
             });