Enable Strict TS API by default (#57490)

Summary:

See [**RFC0894: Removing deep imports from react-native**](react-native-community/discussions-and-proposals#894)

TODO: Description to come.

Differential Revision: D110458670

Author: huntie

.github/workflows/test-all.yml

@@ -471,9 +471,9 @@ jobs:
       - name: Flow
         shell: bash
         run: yarn flow-check
-      - name: TypeScript
+      - name: TypeScript (legacy deep imports / manual types)
         shell: bash
-        run: yarn test-typescript
+        run: yarn test-typescript-legacy
 
   test_js:
     runs-on: ubuntu-latest

package.json

@@ -33,8 +33,8 @@
     "test-release-local-clean": "node ./scripts/release-testing/test-release-local-clean.js",
     "test-release-local": "node ./scripts/release-testing/test-release-local.js",
     "test-ios": "./scripts/objc-test.sh test",
-    "test-typescript": "tsc -p packages/react-native/types/tsconfig.json",
-    "test-generated-typescript": "tsc -p packages/react-native/types_generated/tsconfig.test.json",
+    "test-typescript-legacy": "tsc -p packages/react-native/__typetests__/tsconfig.legacy.json",
+    "test-generated-typescript": "tsc -p packages/react-native/__typetests__/tsconfig.json",
     "test": "jest",
     "fantom": "./scripts/fantom.sh",
     "fantom-cli": "./scripts/fantom-cli.sh",

packages/react-native/__typetests__/tsconfig.json

@@ -0,0 +1,19 @@
+{
+  "$schema": "https://json.schemastore.org/tsconfig",
+  // Default config: resolves `react-native` through the package `exports` map,
+  // which selects the Strict API (`types_generated/`). `tsconfig.legacy.json`
+  // opts back into the legacy deep-import types.
+  "compilerOptions": {
+    "module": "esnext",
+    "lib": ["es2020"],
+    "strict": false,
+    "noImplicitAny": true,
+    "noImplicitThis": true,
+    "types": [],
+    "jsx": "react",
+    "noEmit": true,
+    "forceConsistentCasingInFileNames": true,
+    "moduleResolution": "bundler"
+  },
+  "include": ["**/*"]
+}

packages/react-native/__typetests__/tsconfig.legacy.json

@@ -0,0 +1,10 @@
+{
+  "$schema": "https://json.schemastore.org/tsconfig",
+  // Legacy variant: opts into the `react-native-legacy-deep-imports` export
+  // condition so `react-native` and `react-native/Libraries/*` resolve to the
+  // hand-written types in `types/`.
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "customConditions": ["react-native-legacy-deep-imports"]
+  }
+}

packages/react-native/package.json

@@ -27,20 +27,19 @@
     "react-native": "cli.js"
   },
   "main": "./index.js",
-  "types": "types",
   "exports": {
     ".": {
-      "react-native-strict-api": "./types_generated/index.d.ts",
-      "types": "./types/index.d.ts",
+      "react-native-legacy-deep-imports": "./types/index.d.ts",
+      "types": "./types_generated/index.d.ts",
       "default": "./index.js"
     },
     "./Libraries/*": {
-      "react-native-strict-api": null,
-      "types": "./Libraries/*.d.ts",
+      "react-native-legacy-deep-imports": "./Libraries/*.d.ts",
+      "types": null,
       "default": "./Libraries/*.js"
     },
     "./Libraries/*.js": {
-      "react-native-strict-api": null,
+      "types": null,
       "default": "./Libraries/*.js"
     },
     "./scripts/*": "./scripts/*",

packages/react-native/types/tsconfig.json

@@ -9,25 +9,18 @@ This package provides the default `tsconfig.json` used by newly built React Nati
 
 This template is customized for specific versions of React Native, and should be updated in sync with the rest of your app.
 
-## Strict TypeScript API
+## Opting out of the Strict TypeScript API (default in 0.78)
 
-To opt into the new [strict TypeScript API](https://reactnative.dev/blog/2025/06/12/moving-towards-a-stable-javascript-api#strict-typescript-api-opt-in) you can extend from `@react-native/typescript-config/strict`
+To opt into the new [Strict TypeScript API](https://reactnative.dev/docs/strict-typescript-api) you can extend from `@react-native/typescript-config/strict`
 
-```jsonc
-{
-  "extends": "@react-native/typescript-config/strict",
-  // ...
-}
-```
-
-or alternatively add the `customConditions` yourself:
+If your app still needs access to deep `'react-native/Libraries/*'` imports (deprecated in 0.80), you can opt out via `customConditions` in your `tsconfig.json`:
 
 ```jsonc
 {
   "extends": "@react-native/typescript-config",
   "compilerOptions": {
     // ...
-    "customConditions": ["react-native-strict-api", "react-native"]
+    "customConditions": ["react-native-legacy-deep-imports", "react-native"]
   }
 }
 ```

packages/typescript-config/README.md

@@ -16,7 +16,6 @@
   ],
   "bugs": "https://github.com/react/react-native/issues",
   "exports": {
-    ".": "./tsconfig.json",
-    "./strict": "./tsconfig.strict.json"
+    ".": "./tsconfig.json"
   }
 }

packages/typescript-config/package.json

@@ -21,8 +21,8 @@
   },
   "exports": {
     ".": {
-      "react-native-strict-api": "./types_generated/index.d.ts",
-      "types": "./index.d.ts",
+      "react-native-legacy-deep-imports": "./index.d.ts",
+      "types": "./types_generated/index.d.ts",
       "default": "./index.js"
     },
     "./*": {