diff --git a/src/compiler/builder.ts b/src/compiler/builder.ts
index 8703d83aa1d..40aabb04baa 100644
--- a/src/compiler/builder.ts
+++ b/src/compiler/builder.ts
@@ -331,11 +331,18 @@ namespace ts {
             }
         }
 
+        /**
+         * Returns the result with affected file
+         */
+        function toAffectedFileResult<T>(result: T, affectedFile?: SourceFile): AffectedFileResult<T> {
+            return { result, affectedFile };
+        }
+
         /**
          * Emits the next affected file, and returns the EmitResult along with source files emitted
          * Returns undefined when iteration is complete
          */
-        function emitNextAffectedFile(programOfThisState: Program, writeFileCallback: WriteFileCallback, cancellationToken?: CancellationToken, customTransformers?: CustomTransformers): AffectedFileEmitResult | undefined {
+        function emitNextAffectedFile(programOfThisState: Program, writeFileCallback: WriteFileCallback, cancellationToken?: CancellationToken, customTransformers?: CustomTransformers): AffectedFileResult<EmitResult> {
             const affectedFile = getNextAffectedFile(programOfThisState);
             if (!affectedFile) {
                 // Done
@@ -343,21 +350,22 @@ namespace ts {
             }
             else if (affectedFile === programOfThisState) {
                 // When whole program is affected, do emit only once (eg when --out or --outFile is specified)
-                return programOfThisState.emit(/*targetSourceFile*/ undefined, writeFileCallback, cancellationToken, /*emitOnlyDtsFiles*/ false, customTransformers);
+                return toAffectedFileResult(programOfThisState.emit(/*targetSourceFile*/ undefined, writeFileCallback, cancellationToken, /*emitOnlyDtsFiles*/ false, customTransformers));
             }
 
             // Emit the affected file
             const targetSourceFile = affectedFile as SourceFile;
-            const result = programOfThisState.emit(targetSourceFile, writeFileCallback, cancellationToken, /*emitOnlyDtsFiles*/ false, customTransformers) as AffectedFileEmitResult;
-            result.affectedFile = targetSourceFile;
-            return result;
+            return toAffectedFileResult(
+                programOfThisState.emit(targetSourceFile, writeFileCallback, cancellationToken, /*emitOnlyDtsFiles*/ false, customTransformers),
+                targetSourceFile
+            );
         }
 
         /**
          * Return the semantic diagnostics for the next affected file or undefined if iteration is complete
          * If provided ignoreSourceFile would be called before getting the diagnostics and would ignore the sourceFile if the returned value was true
          */
-        function getSemanticDiagnosticsOfNextAffectedFile(programOfThisState: Program, cancellationToken?: CancellationToken, ignoreSourceFile?: (sourceFile: SourceFile) => boolean): ReadonlyArray<Diagnostic> {
+        function getSemanticDiagnosticsOfNextAffectedFile(programOfThisState: Program, cancellationToken?: CancellationToken, ignoreSourceFile?: (sourceFile: SourceFile) => boolean): AffectedFileResult<ReadonlyArray<Diagnostic>> {
             while (true) {
                 const affectedFile = getNextAffectedFile(programOfThisState);
                 if (!affectedFile) {
@@ -366,7 +374,7 @@ namespace ts {
                 }
                 else if (affectedFile === programOfThisState) {
                     // When whole program is affected, get all semantic diagnostics (eg when --out or --outFile is specified)
-                    return programOfThisState.getSemanticDiagnostics(/*targetSourceFile*/ undefined, cancellationToken);
+                    return toAffectedFileResult(programOfThisState.getSemanticDiagnostics(/*targetSourceFile*/ undefined, cancellationToken));
                 }
 
                 // Get diagnostics for the affected file if its not ignored
@@ -376,7 +384,10 @@ namespace ts {
                     continue;
                 }
 
-                return getSemanticDiagnosticsOfFile(programOfThisState, targetSourceFile, cancellationToken);
+                return toAffectedFileResult(
+                    getSemanticDiagnosticsOfFile(programOfThisState, targetSourceFile, cancellationToken),
+                    targetSourceFile
+                );
             }
         }
 
@@ -682,9 +693,7 @@ namespace ts {
         text: string;
     }
 
-    export interface AffectedFileEmitResult extends EmitResult {
-        affectedFile?: SourceFile;
-    }
+    export type AffectedFileResult<T> = { result: T; affectedFile?: SourceFile; } | undefined;
 
     export interface BuilderOptions {
         getCanonicalFileName: (fileName: string) => string;
@@ -714,7 +723,7 @@ namespace ts {
          * Gets the semantic diagnostics from the program for the next affected file and caches it
          * Returns undefined if the iteration is complete
          */
-        getSemanticDiagnosticsOfNextAffectedFile(programOfThisState: Program, cancellationToken?: CancellationToken, ignoreSourceFile?: (sourceFile: SourceFile) => boolean): ReadonlyArray<Diagnostic>;
+        getSemanticDiagnosticsOfNextAffectedFile(programOfThisState: Program, cancellationToken?: CancellationToken, ignoreSourceFile?: (sourceFile: SourceFile) => boolean): AffectedFileResult<ReadonlyArray<Diagnostic>>;
 
         /**
          * Gets the semantic diagnostics from the program corresponding to this state of file (if provided) or whole program
@@ -733,7 +742,7 @@ namespace ts {
         /**
          * Emits the next affected file's emit result (EmitResult and sourceFiles emitted) or returns undefined if iteration is complete
          */
-        emitNextAffectedFile(programOfThisState: Program, writeFileCallback: WriteFileCallback, cancellationToken?: CancellationToken, customTransformers?: CustomTransformers): AffectedFileEmitResult | undefined;
+        emitNextAffectedFile(programOfThisState: Program, writeFileCallback: WriteFileCallback, cancellationToken?: CancellationToken, customTransformers?: CustomTransformers): AffectedFileResult<EmitResult>;
 
         /**
          * Gets the semantic diagnostics from the program corresponding to this state of file (if provided) or whole program
diff --git a/src/compiler/watch.ts b/src/compiler/watch.ts
index fcb4d98ace0..716846cd606 100644
--- a/src/compiler/watch.ts
+++ b/src/compiler/watch.ts
@@ -116,11 +116,11 @@ namespace ts {
             let sourceMaps: SourceMapData[];
             let emitSkipped: boolean;
 
-            let affectedEmitResult: AffectedFileEmitResult;
+            let affectedEmitResult: AffectedFileResult<EmitResult>;
             while (affectedEmitResult = builder.emitNextAffectedFile(program, writeFile)) {
-                emitSkipped = emitSkipped || affectedEmitResult.emitSkipped;
-                addRange(diagnostics, affectedEmitResult.diagnostics);
-                sourceMaps = addRange(sourceMaps, affectedEmitResult.sourceMaps);
+                emitSkipped = emitSkipped || affectedEmitResult.result.emitSkipped;
+                addRange(diagnostics, affectedEmitResult.result.diagnostics);
+                sourceMaps = addRange(sourceMaps, affectedEmitResult.result.sourceMaps);
             }
 
             if (reportSemanticDiagnostics) {
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index e258d179310..e5ee4d8db6c 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -3771,9 +3771,10 @@ declare namespace ts {
         writeByteOrderMark: boolean;
         text: string;
     }
-    interface AffectedFileEmitResult extends EmitResult {
+    type AffectedFileResult<T> = {
+        result: T;
         affectedFile?: SourceFile;
-    }
+    } | undefined;
     interface BuilderOptions {
         getCanonicalFileName: (fileName: string) => string;
         computeHash: (data: string) => string;
@@ -3799,7 +3800,7 @@ declare namespace ts {
          * Gets the semantic diagnostics from the program for the next affected file and caches it
          * Returns undefined if the iteration is complete
          */
-        getSemanticDiagnosticsOfNextAffectedFile(programOfThisState: Program, cancellationToken?: CancellationToken, ignoreSourceFile?: (sourceFile: SourceFile) => boolean): ReadonlyArray<Diagnostic>;
+        getSemanticDiagnosticsOfNextAffectedFile(programOfThisState: Program, cancellationToken?: CancellationToken, ignoreSourceFile?: (sourceFile: SourceFile) => boolean): AffectedFileResult<ReadonlyArray<Diagnostic>>;
         /**
          * Gets the semantic diagnostics from the program corresponding to this state of file (if provided) or whole program
          * The semantic diagnostics are cached and managed here
@@ -3816,7 +3817,7 @@ declare namespace ts {
         /**
          * Emits the next affected file's emit result (EmitResult and sourceFiles emitted) or returns undefined if iteration is complete
          */
-        emitNextAffectedFile(programOfThisState: Program, writeFileCallback: WriteFileCallback, cancellationToken?: CancellationToken, customTransformers?: CustomTransformers): AffectedFileEmitResult | undefined;
+        emitNextAffectedFile(programOfThisState: Program, writeFileCallback: WriteFileCallback, cancellationToken?: CancellationToken, customTransformers?: CustomTransformers): AffectedFileResult<EmitResult>;
         /**
          * Gets the semantic diagnostics from the program corresponding to this state of file (if provided) or whole program
          * The semantic diagnostics are cached and managed here
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index bac53072302..bd1eff0be6f 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -3718,9 +3718,10 @@ declare namespace ts {
         writeByteOrderMark: boolean;
         text: string;
     }
-    interface AffectedFileEmitResult extends EmitResult {
+    type AffectedFileResult<T> = {
+        result: T;
         affectedFile?: SourceFile;
-    }
+    } | undefined;
     interface BuilderOptions {
         getCanonicalFileName: (fileName: string) => string;
         computeHash: (data: string) => string;
@@ -3746,7 +3747,7 @@ declare namespace ts {
          * Gets the semantic diagnostics from the program for the next affected file and caches it
          * Returns undefined if the iteration is complete
          */
-        getSemanticDiagnosticsOfNextAffectedFile(programOfThisState: Program, cancellationToken?: CancellationToken, ignoreSourceFile?: (sourceFile: SourceFile) => boolean): ReadonlyArray<Diagnostic>;
+        getSemanticDiagnosticsOfNextAffectedFile(programOfThisState: Program, cancellationToken?: CancellationToken, ignoreSourceFile?: (sourceFile: SourceFile) => boolean): AffectedFileResult<ReadonlyArray<Diagnostic>>;
         /**
          * Gets the semantic diagnostics from the program corresponding to this state of file (if provided) or whole program
          * The semantic diagnostics are cached and managed here
@@ -3763,7 +3764,7 @@ declare namespace ts {
         /**
          * Emits the next affected file's emit result (EmitResult and sourceFiles emitted) or returns undefined if iteration is complete
          */
-        emitNextAffectedFile(programOfThisState: Program, writeFileCallback: WriteFileCallback, cancellationToken?: CancellationToken, customTransformers?: CustomTransformers): AffectedFileEmitResult | undefined;
+        emitNextAffectedFile(programOfThisState: Program, writeFileCallback: WriteFileCallback, cancellationToken?: CancellationToken, customTransformers?: CustomTransformers): AffectedFileResult<EmitResult>;
         /**
          * Gets the semantic diagnostics from the program corresponding to this state of file (if provided) or whole program
          * The semantic diagnostics are cached and managed here