diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 4490c240886..7b4b4f03be3 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -562,6 +562,7 @@ namespace ts {
         const prependNodes = createPrependNodes(config.projectReferences, getCommandLine, f => host.readFile(f));
         const jsPrepend = createUnparsedJsSourceFile(ownPrependInput);
         const sourceFilesForJsEmit = createSourceFilesForPrologues(buildInfo.bundle.js);
+        let currentBuildInfoType: "js" | "dts" = "js";
         const emitHost: EmitHost = {
             getPrependNodes: memoize(() => [...prependNodes, jsPrepend]),
             getProjectReferences: () => config.projectReferences,
@@ -576,14 +577,36 @@ namespace ts {
             getLibFileFromReference: notImplemented,
             isSourceFileFromExternalLibrary: returnFalse,
             writeFile: (name, text, writeByteOrderMark) => {
-                if (name !== buildInfoPath) {
-                    outputFiles.push({ name, text, writeByteOrderMark });
-                }
-                else {
-                    // Add dts and sources build info since we are not touching that file
-                    const buildInfo = JSON.parse(text) as BuildInfo;
-                    newBundle.js = buildInfo.bundle && buildInfo.bundle.js;
-                    writeByteOrderMarkBuildInfo = writeByteOrderMarkBuildInfo || writeByteOrderMark;
+                switch (name) {
+                    case jsFilePath:
+                        if (jsFileText !== text) {
+                            outputFiles.push({ name, text, writeByteOrderMark });
+                        }
+                        break;
+                    case sourceMapFilePath:
+                        if (sourceMapText !== text) {
+                            outputFiles.push({ name, text, writeByteOrderMark });
+                        }
+                        break;
+                    case buildInfoPath:
+                        if (currentBuildInfoType === "js" || stripInternal) {
+                            const buildInfo = JSON.parse(text) as BuildInfo;
+                            newBundle[currentBuildInfoType] = buildInfo.bundle && buildInfo.bundle[currentBuildInfoType];
+                            writeByteOrderMarkBuildInfo = writeByteOrderMarkBuildInfo || writeByteOrderMark;
+                        }
+                        break;
+                    case declarationFilePath:
+                        if (stripInternal && declarationText !== text) {
+                            outputFiles.push({ name, text, writeByteOrderMark });
+                        }
+                        break;
+                    case declarationMapPath:
+                        if (declarationMapText !== text) {
+                            outputFiles.push({ name, text, writeByteOrderMark });
+                        }
+                        break;
+                    default:
+                        Debug.assertNever(name as never);
                 }
             },
             isEmitBlocked: returnFalse,
@@ -597,23 +620,11 @@ namespace ts {
         emitFiles(notImplementedResolver, emitHost, /*targetSourceFile*/ undefined, /*emitOnlyDtsFiles*/ false, getTransformers(optionsWithoutDeclaration));
         // Emit d.ts map
         if (shouldHaveDeclarationText) {
+            currentBuildInfoType = "dts";
             const dtsPrepends = prependNodes.map(prepend => createUnparsedSourceFile(prepend, "dts", stripInternal));
             emitHost.getPrependNodes = memoize(() => [...dtsPrepends, createUnparsedDtsSourceFile(ownPrependInput)]);
             emitHost.getCompilerOptions = () => config.options;
             emitHost.getSourceFiles = () => emptyArray;
-            emitHost.writeFile = (name, text, writeByteOrderMark) => {
-                // Same dts ignore
-                if (!stripInternal && (fileExtensionIs(name, Extension.Dts) || name === buildInfoPath)) return;
-                // Even though dts file hasnt changed, whether def is internal or not could change, so write the dts and update buildInfo
-                if (name !== buildInfoPath) {
-                    outputFiles.push({ name, text, writeByteOrderMark });
-                }
-                else {
-                    const buildInfo = JSON.parse(text) as BuildInfo;
-                    newBundle.dts = buildInfo.bundle && buildInfo.bundle.dts;
-                    writeByteOrderMarkBuildInfo = writeByteOrderMarkBuildInfo || writeByteOrderMark;
-                }
-            };
             emitFiles(notImplementedResolver, emitHost, /*targetSourceFile*/ undefined, /*emitOnlyDtsFiles*/ true);
         }
         outputFiles.push({ name: buildInfoPath!, text: getBuildInfoText({ program: buildInfo.program, bundle: newBundle }), writeByteOrderMark: writeByteOrderMarkBuildInfo });
diff --git a/src/testRunner/unittests/tsbuild/outFile.ts b/src/testRunner/unittests/tsbuild/outFile.ts
index ca5b28ca440..67d666b8cd4 100644
--- a/src/testRunner/unittests/tsbuild/outFile.ts
+++ b/src/testRunner/unittests/tsbuild/outFile.ts
@@ -88,14 +88,12 @@ namespace ts {
             modifyAgainFs,
             additionalSourceFiles,
             dependOrdered,
-            unchangedDtsWritesThirdDts,
         }: {
             scenario: string;
             modifyFs: (fs: vfs.FileSystem) => void;
             modifyAgainFs?: (fs: vfs.FileSystem) => void;
             additionalSourceFiles?: ReadonlyArray<string>;
             dependOrdered?: boolean;
-            unchangedDtsWritesThirdDts?: boolean;
         }) {
             const incrementalDtsChanged: ExpectedBuildOutputPerState = {
                 expectedDiagnostics: dependOrdered ?
@@ -161,7 +159,7 @@ namespace ts {
                         [Diagnostics.Updating_unchanged_output_timestamps_of_project_0, sources[project.second][source.config]],
                         [Diagnostics.Project_0_is_out_of_date_because_output_javascript_and_source_map_if_specified_of_its_dependency_1_has_changed, relSources[project.third][source.config], "src/second"],
                         [Diagnostics.Updating_output_javascript_and_javascript_source_map_if_specified_of_project_0, sources[project.third][source.config]],
-                        ...getUnchangedOutputTimeStampUpdateOfProjectThree(),
+                        [Diagnostics.Updating_unchanged_output_timestamps_of_project_0, sources[project.third][source.config]],
                     ] :
                     [
                         getExpectedDiagnosticForProjectsInBuild(relSources[project.first][source.config], relSources[project.second][source.config], relSources[project.third][source.config]),
@@ -170,7 +168,7 @@ namespace ts {
                         [Diagnostics.Project_0_is_up_to_date_because_newest_input_1_is_older_than_oldest_output_2, relSources[project.second][source.config], relSources[project.second][source.ts][part.one], relOutputFiles[project.second][ext.js]],
                         [Diagnostics.Project_0_is_out_of_date_because_output_javascript_and_source_map_if_specified_of_its_dependency_1_has_changed, relSources[project.third][source.config], "src/first"],
                         [Diagnostics.Updating_output_javascript_and_javascript_source_map_if_specified_of_project_0, sources[project.third][source.config]],
-                        ...getUnchangedOutputTimeStampUpdateOfProjectThree(),
+                        [Diagnostics.Updating_unchanged_output_timestamps_of_project_0, sources[project.third][source.config]],
                     ],
                 expectedReadFiles: getReadFilesMap(
                     [
@@ -312,12 +310,6 @@ namespace ts {
                     withoutBuildInfo: incrementalDtsUnchangedWithoutBuildInfo
                 }
             });
-
-            function getUnchangedOutputTimeStampUpdateOfProjectThree(): ReadonlyArray<fakes.ExpectedDiagnostic> {
-                return !unchangedDtsWritesThirdDts ?
-                    [[Diagnostics.Updating_unchanged_output_timestamps_of_project_0, sources[project.third][source.config]]] :
-                    emptyArray;
-            }
         }
 
         verifyOutFileScenario({
@@ -645,27 +637,23 @@ ${internal} enum internalEnum { a, b, c }`);
             scenario: "stripInternal",
             modifyFs: fs => stripInternalScenario(fs),
             modifyAgainFs: fs => replaceText(fs, sources[project.first][source.ts][part.one], `/*@internal*/ interface`, "interface"),
-            unchangedDtsWritesThirdDts: true
         });
 
         verifyOutFileScenario({
             scenario: "stripInternal with comments emit enabled",
             modifyFs: fs => stripInternalScenario(fs, /*removeCommentsDisabled*/ true),
             modifyAgainFs: fs => replaceText(fs, sources[project.first][source.ts][part.one], `/*@internal*/ interface`, "interface"),
-            unchangedDtsWritesThirdDts: true
         });
 
         verifyOutFileScenario({
             scenario: "stripInternal jsdoc style comment",
             modifyFs: fs => stripInternalScenario(fs, /*removeCommentsDisabled*/ false, /*jsDocStyle*/ true),
             modifyAgainFs: fs => replaceText(fs, sources[project.first][source.ts][part.one], `/**@internal*/ interface`, "interface"),
-            unchangedDtsWritesThirdDts: true
         });
 
         verifyOutFileScenario({
             scenario: "stripInternal jsdoc style with comments emit enabled",
             modifyFs: fs => stripInternalScenario(fs, /*removeCommentsDisabled*/ true, /*jsDocStyle*/ true),
-            unchangedDtsWritesThirdDts: true
         });
 
         function makeOneTwoThreeDependOrder(fs: vfs.FileSystem) {
@@ -684,7 +672,6 @@ ${internal} enum internalEnum { a, b, c }`);
             modifyFs: fs => stripInternalWithDependentOrder(fs),
             modifyAgainFs: fs => replaceText(fs, sources[project.first][source.ts][part.one], `/*@internal*/ interface`, "interface"),
             dependOrdered: true,
-            unchangedDtsWritesThirdDts: true
         });
 
         verifyOutFileScenario({
@@ -692,7 +679,6 @@ ${internal} enum internalEnum { a, b, c }`);
             modifyFs: fs => stripInternalWithDependentOrder(fs, /*removeCommentsDisabled*/ true),
             modifyAgainFs: fs => replaceText(fs, sources[project.first][source.ts][part.one], `/*@internal*/ interface`, "interface"),
             dependOrdered: true,
-            unchangedDtsWritesThirdDts: true
         });
 
         verifyOutFileScenario({
@@ -700,14 +686,12 @@ ${internal} enum internalEnum { a, b, c }`);
             modifyFs: fs => stripInternalWithDependentOrder(fs, /*removeCommentsDisabled*/ false, /*jsDocStyle*/ true),
             modifyAgainFs: fs => replaceText(fs, sources[project.first][source.ts][part.one], `/**@internal*/ interface`, "interface"),
             dependOrdered: true,
-            unchangedDtsWritesThirdDts: true
         });
 
         verifyOutFileScenario({
             scenario: "stripInternal jsdoc style with comments emit enabled when one-two-three are prepended in order",
             modifyFs: fs => stripInternalWithDependentOrder(fs, /*removeCommentsDisabled*/ true, /*jsDocStyle*/ true),
             dependOrdered: true,
-            unchangedDtsWritesThirdDts: true
         });
     });
 }