Require TypeScript 5.9

.github/workflows/main.yml

@@ -35,7 +35,6 @@ jobs:
         typescript-version:
           - 'latest'
           - '~5.9.0'
-          - '~5.8.0'
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4

package.json

@@ -52,12 +52,12 @@
 		"tagged-tag": "^1.0.0"
 	},
 	"devDependencies": {
-		"@sindresorhus/tsconfig": "^7.0.0",
-		"expect-type": "^1.2.1",
-		"npm-run-all2": "^8.0.1",
-		"tsd": "^0.32.0",
-		"typescript": "~5.8.3",
-		"xo": "^1.0.5"
+		"@sindresorhus/tsconfig": "^8.0.1",
+		"expect-type": "^1.2.2",
+		"npm-run-all2": "^8.0.4",
+		"tsd": "^0.33.0",
+		"typescript": "^5.9.2",
+		"xo": "^1.2.1"
 	},
 	"tsd": {
 		"compilerOptions": {

readme.md

@@ -55,7 +55,7 @@ PR welcome for additional commonly needed types and docs improvements. Read the
 npm install type-fest
 ```
 
-*Requires TypeScript >=5.8, [ESM](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c), and [`{strict: true}`](https://www.typescriptlang.org/tsconfig#strict) in your tsconfig.*
+*Requires TypeScript >=5.9, [ESM](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c), and [`{strict: true}`](https://www.typescriptlang.org/tsconfig#strict) in your tsconfig.*
 
 > [!NOTE]
 > This readme shows the current development version. For docs about the latest version, see the [npm page](https://www.npmjs.com/package/type-fest).

tsconfig.json

@@ -4,14 +4,9 @@
 		"noEmit": true,
 		"allowJs": true,
 		"noUnusedLocals": false, // Allow unused variables in test-d/*.ts files
-		"module": "node18",
-		"target": "ES2023", // Node.js 20
-		"lib": [
-			"ES2023",
-			"DOM"
-		],
 		"types": [], // Ensures no @types/ are unintentionally included
 		"exactOptionalPropertyTypes": true,
 		"skipLibCheck": false, // Ensures .d.ts files are checked: https://github.com/sindresorhus/tsconfig/issues/15
+		"erasableSyntaxOnly": false // We cannot do this as we need to be able to test enums.
 	}
 }