diff --git a/packages/header-parser/test/index.test.ts b/packages/header-parser/test/index.test.ts
index 2d1f6cfa..f89b8158 100644
--- a/packages/header-parser/test/index.test.ts
+++ b/packages/header-parser/test/index.test.ts
@@ -169,7 +169,18 @@ describe("isTypeScriptVersion", () => {
 
 describe("range", () => {
   it("works", () => {
-    expect(TypeScriptVersion.range("4.1")).toEqual(["4.1", "4.2", "4.3", "4.4", "4.5", "4.6", "4.7", "4.8", "4.9", "5.0"]);
+    expect(TypeScriptVersion.range("4.1")).toEqual([
+      "4.1",
+      "4.2",
+      "4.3",
+      "4.4",
+      "4.5",
+      "4.6",
+      "4.7",
+      "4.8",
+      "4.9",
+      "5.0",
+    ]);
   });
   it.skip("includes 4.2 onwards", () => {
     expect(TypeScriptVersion.range("4.2")).toEqual(TypeScriptVersion.supported);
diff --git a/packages/typescript-versions/src/index.ts b/packages/typescript-versions/src/index.ts
index ada2beb2..ae4b2808 100644
--- a/packages/typescript-versions/src/index.ts
+++ b/packages/typescript-versions/src/index.ts
@@ -49,7 +49,7 @@ export type UnsupportedTypeScriptVersion =
   | "3.7"
   | "3.8"
   | "3.9"
-  | "4.0"
+  | "4.0";
 /**
  * Parseable and supported TypeScript versions.
  * Only add to this list if we will support this version on Definitely Typed.