From 70111bc003f7ea75853a06d3096f26556c6fad21 Mon Sep 17 00:00:00 2001
From: Jake Bailey <5341706+jakebailey@users.noreply.github.com>
Date: Wed, 19 Feb 2025 17:08:30 -0800
Subject: [PATCH] Support TS 5.9 (#1143)

---
 .changeset/little-pugs-lick.md                  |  6 ++++++
 packages/typescript-packages/package.json       |  3 ++-
 packages/typescript-versions/src/index.ts       |  2 +-
 packages/typescript-versions/test/index.test.ts |  3 ++-
 pnpm-lock.yaml                                  | 10 ++++++++++
 5 files changed, 21 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/little-pugs-lick.md

diff --git a/.changeset/little-pugs-lick.md b/.changeset/little-pugs-lick.md
new file mode 100644
index 0000000000..e62a7a1aca
--- /dev/null
+++ b/.changeset/little-pugs-lick.md
@@ -0,0 +1,6 @@
+---
+"@definitelytyped/typescript-packages": patch
+"@definitelytyped/typescript-versions": patch
+---
+
+Support TS 5.9
diff --git a/packages/typescript-packages/package.json b/packages/typescript-packages/package.json
index 60b8b47e6a..d9881392b5 100644
--- a/packages/typescript-packages/package.json
+++ b/packages/typescript-packages/package.json
@@ -30,6 +30,7 @@
     "typescript-5.5": "npm:typescript@~5.5.0-0",
     "typescript-5.6": "npm:typescript@~5.6.0-0",
     "typescript-5.7": "npm:typescript@~5.7.0-0",
-    "typescript-5.8": "npm:typescript@~5.8.0-0"
+    "typescript-5.8": "npm:typescript@~5.8.0-0",
+    "typescript-5.9": "npm:typescript@~5.9.0-0"
   }
 }
diff --git a/packages/typescript-versions/src/index.ts b/packages/typescript-versions/src/index.ts
index a3cd6bba33..3c76bc0bc2 100644
--- a/packages/typescript-versions/src/index.ts
+++ b/packages/typescript-versions/src/index.ts
@@ -43,7 +43,7 @@ export namespace TypeScriptVersion {
   /** Add to this list when a version actually ships.  */
   export const shipped = ["5.0", "5.1", "5.2", "5.3", "5.4", "5.5", "5.6", "5.7"] as const;
   /** Add to this list when a version is available as typescript@next */
-  export const supported = [...shipped, "5.8"] as const;
+  export const supported = [...shipped, "5.8", "5.9"] as const;
   /** Add to this list when it will no longer be supported on Definitely Typed */
   export const unsupported = [
     "2.0",
diff --git a/packages/typescript-versions/test/index.test.ts b/packages/typescript-versions/test/index.test.ts
index 87f82238bf..18c202c8f2 100644
--- a/packages/typescript-versions/test/index.test.ts
+++ b/packages/typescript-versions/test/index.test.ts
@@ -42,7 +42,7 @@ describe("isTypeScriptVersion", () => {
 
 describe("range", () => {
   it("works", () => {
-    expect(TypeScriptVersion.range("5.1")).toEqual(["5.1", "5.2", "5.3", "5.4", "5.5", "5.6", "5.7", "5.8"]);
+    expect(TypeScriptVersion.range("5.1")).toEqual(["5.1", "5.2", "5.3", "5.4", "5.5", "5.6", "5.7", "5.8", "5.9"]);
   });
   it("includes 5.0 onwards", () => {
     expect(TypeScriptVersion.range("5.0")).toEqual(TypeScriptVersion.supported);
@@ -60,6 +60,7 @@ describe("tagsToUpdate", () => {
       "ts5.6",
       "ts5.7",
       "ts5.8",
+      "ts5.9",
       "latest",
     ]);
   });
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index bbbb8d0560..f948c1ddee 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -463,6 +463,9 @@ importers:
       typescript-5.8:
         specifier: npm:typescript@~5.8.0-0
         version: typescript@5.8.0-dev.20241123
+      typescript-5.9:
+        specifier: npm:typescript@~5.9.0-0
+        version: typescript@5.9.0-dev.20250219
 
   packages/typescript-versions: {}
 
@@ -4798,6 +4801,11 @@ packages:
     engines: {node: '>=14.17'}
     hasBin: true
 
+  typescript@5.9.0-dev.20250219:
+    resolution: {integrity: sha512-BzBFdaj0tnTp9fp9pu1rgi7vt3u7z6EDL3IbjTgkf5GvpXTjWmQkE633De5S3ySeNL6dyZvBeVvLCKXKcOvbQA==}
+    engines: {node: '>=14.17'}
+    hasBin: true
+
   unbox-primitive@1.0.2:
     resolution: {integrity: sha512-61pPlCD9h51VoreyJ0BReideM3MDKMKnh6+V9L08331ipq6Q8OFXZYiqP6n/tbHx4s5I9uRhcye6BrbkizkBDw==}
 
@@ -10311,6 +10319,8 @@ snapshots:
 
   typescript@5.8.0-dev.20241123: {}
 
+  typescript@5.9.0-dev.20250219: {}
+
   unbox-primitive@1.0.2:
     dependencies:
       call-bind: 1.0.7