diff --git a/packages/typescript/src/index.ts b/packages/typescript/src/index.ts
index 293e341d9..bea3e736d 100644
--- a/packages/typescript/src/index.ts
+++ b/packages/typescript/src/index.ts
@@ -17,7 +17,7 @@ import findTypescriptOutput, {
   normalizePath,
   emitFile,
   isDeclarationOutputFile,
-  isMapOutputFile
+  isTypeScriptMapOutputFile
 } from './outputFile';
 import { preflight } from './preflight';
 import createWatchProgram, { WatchProgramHelper } from './watchProgram';
@@ -156,11 +156,11 @@ export default function typescript(options: RollupTypescriptOptions = {}): Plugi
     },
 
     async generateBundle(outputOptions) {
-      const declarationAndMapFiles = [...emittedFiles.keys()].filter(
-        (fileName) => isDeclarationOutputFile(fileName) || isMapOutputFile(fileName)
+      const declarationAndTypeScriptMapFiles = [...emittedFiles.keys()].filter(
+        (fileName) => isDeclarationOutputFile(fileName) || isTypeScriptMapOutputFile(fileName)
       );
 
-      declarationAndMapFiles.forEach((id) => {
+      declarationAndTypeScriptMapFiles.forEach((id) => {
         const code = getEmittedFile(id, emittedFiles, tsCache);
         if (!code || !parsedOptions.options.declaration) {
           return;
diff --git a/packages/typescript/src/outputFile.ts b/packages/typescript/src/outputFile.ts
index 4dc0de04d..d7b080ab1 100644
--- a/packages/typescript/src/outputFile.ts
+++ b/packages/typescript/src/outputFile.ts
@@ -24,6 +24,13 @@ export function isCodeOutputFile(name: string): boolean {
  * Checks if the given OutputFile represents some source map
  */
 export function isMapOutputFile(name: string): boolean {
+  return name.endsWith('.map');
+}
+
+/**
+ * Checks if the given OutputFile represents some TypeScript source map
+ */
+export function isTypeScriptMapOutputFile(name: string): boolean {
   return name.endsWith('ts.map');
 }