diff --git a/src/harness/unittests/extractMethods.ts b/src/harness/unittests/extractMethods.ts
index c148d6d58a5..971d918cb33 100644
--- a/src/harness/unittests/extractMethods.ts
+++ b/src/harness/unittests/extractMethods.ts
@@ -550,7 +550,7 @@ namespace A {
 
     function testExtractMethod(caption: string, text: string) {
         it(caption, () => {
-            Harness.Baseline.runBaseline(`extractMethod/${caption}.js`, () => {
+            Harness.Baseline.runBaseline(`extractMethod/${caption}.ts`, () => {
                 const t = extractTest(text);
                 const selectionRange = t.ranges.get("selection");
                 if (!selectionRange) {
diff --git a/tests/baselines/reference/extractMethod/extractMethod1.js b/tests/baselines/reference/extractMethod/extractMethod1.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod1.js
rename to tests/baselines/reference/extractMethod/extractMethod1.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod10.js b/tests/baselines/reference/extractMethod/extractMethod10.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod10.js
rename to tests/baselines/reference/extractMethod/extractMethod10.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod11.js b/tests/baselines/reference/extractMethod/extractMethod11.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod11.js
rename to tests/baselines/reference/extractMethod/extractMethod11.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod12.js b/tests/baselines/reference/extractMethod/extractMethod12.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod12.js
rename to tests/baselines/reference/extractMethod/extractMethod12.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod2.js b/tests/baselines/reference/extractMethod/extractMethod2.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod2.js
rename to tests/baselines/reference/extractMethod/extractMethod2.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod3.js b/tests/baselines/reference/extractMethod/extractMethod3.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod3.js
rename to tests/baselines/reference/extractMethod/extractMethod3.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod4.js b/tests/baselines/reference/extractMethod/extractMethod4.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod4.js
rename to tests/baselines/reference/extractMethod/extractMethod4.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod5.js b/tests/baselines/reference/extractMethod/extractMethod5.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod5.js
rename to tests/baselines/reference/extractMethod/extractMethod5.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod6.js b/tests/baselines/reference/extractMethod/extractMethod6.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod6.js
rename to tests/baselines/reference/extractMethod/extractMethod6.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod7.js b/tests/baselines/reference/extractMethod/extractMethod7.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod7.js
rename to tests/baselines/reference/extractMethod/extractMethod7.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod8.js b/tests/baselines/reference/extractMethod/extractMethod8.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod8.js
rename to tests/baselines/reference/extractMethod/extractMethod8.ts
diff --git a/tests/baselines/reference/extractMethod/extractMethod9.js b/tests/baselines/reference/extractMethod/extractMethod9.ts
similarity index 100%
rename from tests/baselines/reference/extractMethod/extractMethod9.js
rename to tests/baselines/reference/extractMethod/extractMethod9.ts