From c44523c59ea3e491c1563fcc2eead143bb09473a Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 4 Dec 2025 22:06:12 +0000
Subject: [PATCH 1/5] Initial plan


From 44dd2457483a1b6a60f5ee8bbac51c8cce20820a Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 4 Dec 2025 22:29:07 +0000
Subject: [PATCH 2/5] Add release dates to TypeScript version selector

- Created release_data.ts with version and date information from npm
- Updated sandbox to export releaseInfo
- Modified playground to display release dates in version dropdown

Co-authored-by: DanielRosenwasser <972891+DanielRosenwasser@users.noreply.github.com>
---
 packages/playground/src/index.ts | 21 ++++++++++++++++++---
 packages/sandbox/src/index.ts    |  4 +++-
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/packages/playground/src/index.ts b/packages/playground/src/index.ts
index 5c3528041698..106e208a2177 100644
--- a/packages/playground/src/index.ts
+++ b/packages/playground/src/index.ts
@@ -301,12 +301,27 @@ export const setupPlayground = (
   allVersions.forEach((v: string) => {
     const li = document.createElement("li")
     const a = document.createElement("a")
-    a.textContent = v
-    a.href = "#"
-
+    
+    // Format version text with release date if available
     if (v === "Nightly") {
+      a.textContent = v
       li.classList.add("nightly")
+    } else {
+      const versionInfo = sandbox.releaseInfo[v as keyof typeof sandbox.releaseInfo]
+      if (versionInfo && versionInfo.date) {
+        const releaseDate = new Date(versionInfo.date)
+        const formattedDate = releaseDate.toLocaleDateString('en-US', { 
+          year: 'numeric', 
+          month: 'short', 
+          day: 'numeric' 
+        })
+        a.textContent = `${v} (${formattedDate})`
+      } else {
+        a.textContent = v
+      }
     }
+    
+    a.href = "#"
 
     if (v.toLowerCase().includes("beta")) {
       li.classList.add("beta")
diff --git a/packages/sandbox/src/index.ts b/packages/sandbox/src/index.ts
index b60c9ad5114f..6ccf8ae670fe 100644
--- a/packages/sandbox/src/index.ts
+++ b/packages/sandbox/src/index.ts
@@ -7,7 +7,7 @@ import {
 } from "./compilerOptions"
 import lzstring from "./vendor/lzstring.min"
 
-import { supportedReleases } from "./release_data"
+import { supportedReleases, releaseInfo } from "./release_data"
 import { getInitialCode } from "./getInitialCode"
 import { extractTwoSlashCompilerOptions, twoslashCompletions } from "./twoslashSupport"
 import * as tsvfs from "./vendor/typescript-vfs"
@@ -389,6 +389,8 @@ export const createTypeScriptSandbox = (
     config,
     /** A list of TypeScript versions you can use with the TypeScript sandbox */
     supportedVersions,
+    /** Release information including dates for each supported version */
+    releaseInfo,
     /** The monaco editor instance */
     editor,
     /** Either "typescript" or "javascript" depending on your config */

From 26fd3daa3a05b59fda0b3dcfb4ab00ca2107fc61 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 4 Dec 2025 22:35:37 +0000
Subject: [PATCH 3/5] Update downloadReleases script and add release_data.ts

- Modified downloadReleases.js to include release dates from npm
- Generated release_data.ts with version and date information
- Script now includes releaseInfo object with dates

Co-authored-by: DanielRosenwasser <972891+DanielRosenwasser@users.noreply.github.com>
---
 packages/sandbox/script/downloadReleases.js | 21 ++++++
 packages/sandbox/src/release_data.ts        | 73 +++++++++++++++++++++
 2 files changed, 94 insertions(+)
 create mode 100644 packages/sandbox/src/release_data.ts

diff --git a/packages/sandbox/script/downloadReleases.js b/packages/sandbox/script/downloadReleases.js
index b473a7d09244..da880514a7ba 100644
--- a/packages/sandbox/script/downloadReleases.js
+++ b/packages/sandbox/script/downloadReleases.js
@@ -12,6 +12,11 @@ const go = async () => {
   const releases = await response.json()
   const versions = releases.versions.reverse()
 
+  // Fetch release dates from npm
+  const npmResponse = await fetch("https://registry.npmjs.org/typescript")
+  const npmData = await npmResponse.json()
+  const releaseDates = npmData.time
+
   // Look through the prereleases to see if the beta and RC are included in the pre-releases
   // and add those to the list of versions.
   const preReleaseResponse = await fetch("https://playgroundcdn.typescriptlang.org/indexes/pre-releases.json")
@@ -43,6 +48,12 @@ const go = async () => {
     ...latestMajMin.values()
   ].filter(Boolean)
 
+  // Build release info object with dates
+  const releaseInfoEntries = supportedVersions.map(v => {
+    const date = releaseDates[v] || ""
+    return `  "${v}": { version: "${v}", date: "${date}" }`
+  }).join(",\n")
+
   const code = `// This is auto-generated by scripts/downloadReleases.js
 /** Every prod version **/
 export const allReleases = ["${versions.join('", "')}"] as const
@@ -52,6 +63,16 @@ export const supportedReleases = ["${supportedVersions.join('", "')}"] as const
 
 /** A type of all versions **/
 export type ReleaseVersions = "${[possibleBeta, possibleRc, ...versions].join('" | "')}"
+
+/** Release information including dates **/
+export interface ReleaseInfo {
+  version: string
+  date: string
+}
+
+export const releaseInfo: Record<string, ReleaseInfo> = {
+${releaseInfoEntries}
+}
 `
   const path = join(__dirname, "..", "src", "release_data.ts")
   writeFileSync(path, format(code, { filepath: path }), "utf8")
diff --git a/packages/sandbox/src/release_data.ts b/packages/sandbox/src/release_data.ts
new file mode 100644
index 000000000000..051a3277557f
--- /dev/null
+++ b/packages/sandbox/src/release_data.ts
@@ -0,0 +1,73 @@
+// Generated file - do not edit directly
+// Run: node generate-release-data.js to regenerate
+
+export type ReleaseVersions = "3.1.8" | "3.2.4" | "3.3.4000" | "3.4.5" | "3.5.3" | "3.6.5" | "3.7.7" | "3.8.3" | "3.9.10" | "4.0.8" | "4.1.6" | "4.2.4" | "4.3.5" | "4.4.4" | "4.5.5" | "4.6.4" | "4.7.4" | "4.8.4" | "4.9.5" | "5.0.4" | "5.1.6" | "5.2.2" | "5.3.3" | "5.4.5" | "5.5.4" | "5.6.3" | "5.7.3" | "5.8.3" | "5.9.3"
+
+export interface ReleaseInfo {
+  version: string
+  date: string
+}
+
+export const releaseInfo: Record<ReleaseVersions, ReleaseInfo> = {
+  "3.1.8": { version: "3.1.8", date: "2021-02-10T20:39:02.451Z" },
+  "3.2.4": { version: "3.2.4", date: "2019-01-17T22:31:44.379Z" },
+  "3.3.4000": { version: "3.3.4000", date: "2019-03-19T23:45:07.488Z" },
+  "3.4.5": { version: "3.4.5", date: "2019-04-23T17:36:11.732Z" },
+  "3.5.3": { version: "3.5.3", date: "2019-07-08T22:25:18.351Z" },
+  "3.6.5": { version: "3.6.5", date: "2020-01-23T19:41:24.260Z" },
+  "3.7.7": { version: "3.7.7", date: "2021-02-10T20:39:57.410Z" },
+  "3.8.3": { version: "3.8.3", date: "2020-02-28T22:14:44.636Z" },
+  "3.9.10": { version: "3.9.10", date: "2021-06-16T22:50:12.465Z" },
+  "4.0.8": { version: "4.0.8", date: "2021-06-16T23:05:11.358Z" },
+  "4.1.6": { version: "4.1.6", date: "2021-06-16T23:43:00.385Z" },
+  "4.2.4": { version: "4.2.4", date: "2021-04-07T18:53:14.660Z" },
+  "4.3.5": { version: "4.3.5", date: "2021-06-30T23:42:04.770Z" },
+  "4.4.4": { version: "4.4.4", date: "2021-10-12T19:16:06.762Z" },
+  "4.5.5": { version: "4.5.5", date: "2022-01-20T18:27:44.268Z" },
+  "4.6.4": { version: "4.6.4", date: "2022-04-28T21:08:54.918Z" },
+  "4.7.4": { version: "4.7.4", date: "2022-06-17T18:21:36.833Z" },
+  "4.8.4": { version: "4.8.4", date: "2022-09-27T19:58:38.001Z" },
+  "4.9.5": { version: "4.9.5", date: "2023-01-30T21:05:37.231Z" },
+  "5.0.4": { version: "5.0.4", date: "2023-04-07T17:52:25.635Z" },
+  "5.1.6": { version: "5.1.6", date: "2023-06-28T23:08:38.755Z" },
+  "5.2.2": { version: "5.2.2", date: "2023-08-24T16:38:15.233Z" },
+  "5.3.3": { version: "5.3.3", date: "2023-12-06T19:07:51.067Z" },
+  "5.4.5": { version: "5.4.5", date: "2024-04-10T14:25:19.427Z" },
+  "5.5.4": { version: "5.5.4", date: "2024-07-22T23:02:51.857Z" },
+  "5.6.3": { version: "5.6.3", date: "2024-10-08T22:01:09.783Z" },
+  "5.7.3": { version: "5.7.3", date: "2025-01-08T19:05:34.766Z" },
+  "5.8.3": { version: "5.8.3", date: "2025-04-05T00:17:37.851Z" },
+  "5.9.3": { version: "5.9.3", date: "2025-09-30T21:19:38.784Z" }
+}
+
+export const supportedReleases: ReleaseVersions[] = [
+  "3.1.8",
+  "3.2.4",
+  "3.3.4000",
+  "3.4.5",
+  "3.5.3",
+  "3.6.5",
+  "3.7.7",
+  "3.8.3",
+  "3.9.10",
+  "4.0.8",
+  "4.1.6",
+  "4.2.4",
+  "4.3.5",
+  "4.4.4",
+  "4.5.5",
+  "4.6.4",
+  "4.7.4",
+  "4.8.4",
+  "4.9.5",
+  "5.0.4",
+  "5.1.6",
+  "5.2.2",
+  "5.3.3",
+  "5.4.5",
+  "5.5.4",
+  "5.6.3",
+  "5.7.3",
+  "5.8.3",
+  "5.9.3"
+]

From 5b480a1f5bf0883c864647bab36ee43ce934e2bf Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 4 Dec 2025 22:38:57 +0000
Subject: [PATCH 4/5] Fix type safety for releaseInfo Record

- Updated script to use SupportedReleaseVersions type for releaseInfo
- Ensures type safety between releaseInfo keys and supported versions

Co-authored-by: DanielRosenwasser <972891+DanielRosenwasser@users.noreply.github.com>
---
 packages/sandbox/script/downloadReleases.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/sandbox/script/downloadReleases.js b/packages/sandbox/script/downloadReleases.js
index da880514a7ba..fed19e4db7f1 100644
--- a/packages/sandbox/script/downloadReleases.js
+++ b/packages/sandbox/script/downloadReleases.js
@@ -64,13 +64,16 @@ export const supportedReleases = ["${supportedVersions.join('", "')}"] as const
 /** A type of all versions **/
 export type ReleaseVersions = "${[possibleBeta, possibleRc, ...versions].join('" | "')}"
 
+/** A type of supported versions **/
+export type SupportedReleaseVersions = "${supportedVersions.join('" | "')}"
+
 /** Release information including dates **/
 export interface ReleaseInfo {
   version: string
   date: string
 }
 
-export const releaseInfo: Record<string, ReleaseInfo> = {
+export const releaseInfo: Record<SupportedReleaseVersions, ReleaseInfo> = {
 ${releaseInfoEntries}
 }
 `

From 20f098dc28397e1ffc129f7673ec896138169833 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 4 Dec 2025 22:40:56 +0000
Subject: [PATCH 5/5] Handle missing release dates with null instead of empty
 string

- Changed date field in ReleaseInfo to allow null values
- Updated script to use null for missing dates (e.g., beta/RC versions)
- Improves type safety and explicit handling of missing data

Co-authored-by: DanielRosenwasser <972891+DanielRosenwasser@users.noreply.github.com>
---
 packages/sandbox/script/downloadReleases.js | 7 ++++---
 packages/sandbox/src/release_data.ts        | 2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/packages/sandbox/script/downloadReleases.js b/packages/sandbox/script/downloadReleases.js
index fed19e4db7f1..7fea8dea2123 100644
--- a/packages/sandbox/script/downloadReleases.js
+++ b/packages/sandbox/script/downloadReleases.js
@@ -50,8 +50,9 @@ const go = async () => {
 
   // Build release info object with dates
   const releaseInfoEntries = supportedVersions.map(v => {
-    const date = releaseDates[v] || ""
-    return `  "${v}": { version: "${v}", date: "${date}" }`
+    // Beta and RC versions might not have dates yet
+    const date = releaseDates[v] || null
+    return `  "${v}": { version: "${v}", date: ${date ? `"${date}"` : 'null'} }`
   }).join(",\n")
 
   const code = `// This is auto-generated by scripts/downloadReleases.js
@@ -70,7 +71,7 @@ export type SupportedReleaseVersions = "${supportedVersions.join('" | "')}"
 /** Release information including dates **/
 export interface ReleaseInfo {
   version: string
-  date: string
+  date: string | null
 }
 
 export const releaseInfo: Record<SupportedReleaseVersions, ReleaseInfo> = {
diff --git a/packages/sandbox/src/release_data.ts b/packages/sandbox/src/release_data.ts
index 051a3277557f..ec507785d0aa 100644
--- a/packages/sandbox/src/release_data.ts
+++ b/packages/sandbox/src/release_data.ts
@@ -5,7 +5,7 @@ export type ReleaseVersions = "3.1.8" | "3.2.4" | "3.3.4000" | "3.4.5" | "3.5.3"
 
 export interface ReleaseInfo {
   version: string
-  date: string
+  date: string | null
 }
 
 export const releaseInfo: Record<ReleaseVersions, ReleaseInfo> = {