Adopt TypeScript 6

.gitignore

@@ -1,4 +1,5 @@
 /.cache
+/.claude
 /coverage
 /dist
 /lib

eslint.config.js

@@ -13,7 +13,7 @@ import { defineConfig, globalIgnores } from 'eslint/config';
 import tseslint from 'typescript-eslint';
 
 export default defineConfig([
-  globalIgnores(['.cache', '.nitro', '.output', '.tanstack', 'coverage', 'dist', 'lib']),
+  globalIgnores(['.cache', '.claude', '.nitro', '.output', '.tanstack', 'coverage', 'dist', 'lib']),
 
   {
     linterOptions: {

package.json

@@ -75,7 +75,7 @@
     "react-dom": "^19.2.1",
     "rolldown": "1.0.0-rc.5",
     "rolldown-plugin-dts": "^0.22.1",
-    "typescript": "~5.9.2",
+    "typescript": "~6.0.1-rc",
     "typescript-eslint": "^8.56.0",
     "vite": "^8.0.0-beta.16",
     "vitest": "^4.0.17",
@@ -86,6 +86,7 @@
     "react-dom": "^19.2"
   },
   "overrides": {
+    "typescript": "$typescript",
     "vite": "$vite"
   }
 }

rolldown.config.ts

@@ -22,7 +22,7 @@ export default defineConfig({
       classPrefix: `rdg-${pkg.version.replaceAll('.', '-')}-`
     }),
     dts({
-      tsconfig: './tsconfig.lib.json'
+      tsconfig: './tsconfig.src.json'
     })
   ]
 });

src/EditCell.tsx

@@ -11,21 +11,6 @@ import type {
   RenderEditCellProps
 } from './types';
 
-declare global {
-  const scheduler: Scheduler | undefined;
-}
-
-interface Scheduler {
-  readonly postTask?: (
-    callback: () => void,
-    options?: {
-      priority?: 'user-blocking' | 'user-visible' | 'background';
-      signal?: AbortSignal;
-      delay?: number;
-    }
-  ) => Promise<unknown>;
-}
-
 /*
  * To check for outside `mousedown` events, we listen to all `mousedown` events at their birth,
  * i.e. on the window during the capture phase, and at their death, i.e. on the window during the bubble phase.

src/css.d.ts

@@ -0,0 +1 @@
+declare module '*.css' {}

src/globals.d.ts

@@ -5,5 +5,5 @@ declare module 'react' {
   }
 }
 
-// somehow required to make `declare global` work
+// somehow required to make types work
 export {};

test/globals.d.ts

@@ -9,5 +9,5 @@ declare module 'vitest/browser' {
   }
 }
 
-// somehow required to make `declare global` work
+// somehow required to make types work
 export {};

tsconfig.base.json

@@ -1,26 +1,19 @@
 {
   "compilerOptions": {
-    "allowSyntheticDefaultImports": true,
     "composite": true,
     "emitDeclarationOnly": true,
     "erasableSyntaxOnly": true,
     "exactOptionalPropertyTypes": true,
-    "forceConsistentCasingInFileNames": true,
     "isolatedModules": true,
     "jsx": "react-jsx",
-    "lib": ["ESNext"],
-    "libReplacement": false,
-    "module": "esnext",
+    "lib": [],
     "moduleDetection": "force",
     "moduleResolution": "bundler",
     "noImplicitReturns": true,
     "noUnusedLocals": true,
     "outDir": "./.cache/ts",
-    "pretty": true,
-    "strict": true,
+    "strictNullChecks": true, // TODO: remove once `typescript-eslint` supports TS 6
     "target": "esnext",
-    "types": [],
-    "useUnknownInCatchVariables": true,
     "verbatimModuleSyntax": true
   }
 }

tsconfig.js.json

@@ -3,6 +3,7 @@
   "compilerOptions": {
     "allowJs": true,
     "checkJs": true,
+    "lib": ["ESNext"],
     "module": "NodeNext",
     "moduleResolution": "NodeNext"
   },

tsconfig.src.json

@@ -1,7 +1,7 @@
 {
   "extends": "./tsconfig.base.json",
   "compilerOptions": {
-    "lib": ["ESNext", "DOM", "DOM.Iterable", "DOM.AsyncIterable"]
+    "lib": ["ESNext", "DOM"]
   },
   "include": ["src/**/*"]
 }

tsconfig.test.json

@@ -1,7 +1,7 @@
 {
   "extends": "./tsconfig.base.json",
   "compilerOptions": {
-    "lib": ["ESNext", "DOM", "DOM.Iterable", "DOM.AsyncIterable"],
+    "lib": ["ESNext", "DOM"],
     "skipLibCheck": true,
     "types": ["vitest/globals"]
   },

tsconfig.website.json

@@ -1,9 +1,9 @@
 {
   "extends": "./tsconfig.base.json",
   "compilerOptions": {
-    "lib": ["ESNext", "DOM", "DOM.Iterable", "DOM.AsyncIterable"],
+    "lib": ["ESNext", "DOM"],
     "skipLibCheck": true
   },
-  "include": ["website/**/*"],
+  "include": ["src/css.d.ts", "website/**/*"],
   "references": [{ "path": "tsconfig.src.json" }]
 }