first commit

examples/with-context-api/.gitignore

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+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.*
+.yarn/*
+!.yarn/patches
+!.yarn/plugins
+!.yarn/releases
+!.yarn/versions
+
+# testing
+/coverage
+
+# next.js
+/.next/
+/out/
+
+# production
+/build
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+.pnpm-debug.log*
+
+# local env files
+.env*.local
+
+# vercel
+.vercel
+
+# typescript
+*.tsbuildinfo
+next-env.d.ts

examples/with-context-api/README.md

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+# Hello World example
+
+This example shows how to use react context api in our app.
+
+It provides an example of using `app/layout.tsx` to include the context api provider and then shows how both the `app/page.tsx` and `app/about/page.tsx` can both share the same data using the context api consumer.
+
+We start off by creating two contexts. One that actually never changes (`CounterDispatchContext`) and one that changes more often (`CounterStateContext`).
+
+The `app/page.tsx` shows how to, from the home page, increment and decrement the context data by 1 (a hard code value in the context provider itself).
+
+The `app/about/page.tsx` shows how to pass an increment value from the about page into the context provider itself.
+
+## Deploy your own
+
+[![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/new/clone?repository-url=https://github.com/vercel/next.js/tree/canary/examples/with-context-api&project-name=with-context-api&repository-name=with-context-api)
+
+## How to use
+
+Execute [`create-next-app`](https://github.com/vercel/next.js/tree/canary/packages/create-next-app) with [npm](https://docs.npmjs.com/cli/init), [Yarn](https://yarnpkg.com/lang/en/docs/cli/create/), or [pnpm](https://pnpm.io) to bootstrap the example:
+
+```bash
+npx create-next-app --example with-context-api with-context-api-app
+```
+
+```bash
+yarn create next-app --example with-context-api with-context-api-app
+```
+
+```bash
+pnpm create next-app --example with-context-api with-context-api-app
+```
+
+Deploy it to the cloud with [Vercel](https://vercel.com/new?utm_source=github&utm_medium=readme&utm_campaign=next-example) ([Documentation](https://nextjs.org/docs/deployment)).

examples/with-context-api/_components/Counter.tsx

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+"use client";
+
+import {
+  useReducer,
+  useContext,
+  createContext,
+  ReactNode,
+  Dispatch,
+} from "react";
+
+type CounterState = number;
+type CounterAction =
+  | {
+      type: "INCREASE" | "DECREASE";
+    }
+  | {
+      type: "INCREASE_BY";
+      payload: number;
+    };
+
+const CounterStateContext = createContext<CounterState>(0);
+const CounterDispatchContext = createContext<Dispatch<CounterAction>>(
+  () => null,
+);
+
+const reducer = (state: CounterState, action: CounterAction) => {
+  switch (action.type) {
+    case "INCREASE":
+      return state + 1;
+    case "DECREASE":
+      return state - 1;
+    case "INCREASE_BY":
+      return state + action.payload;
+    default:
+      throw new Error(`Unknown action: ${JSON.stringify(action)}`);
+  }
+};
+
+type CounterProviderProps = {
+  children: ReactNode;
+  initialValue?: number;
+};
+
+export const CounterProvider = ({
+  children,
+  initialValue = 0,
+}: CounterProviderProps) => {
+  const [state, dispatch] = useReducer(reducer, initialValue);
+  return (
+    <CounterDispatchContext.Provider value={dispatch}>
+      <CounterStateContext.Provider value={state}>
+        {children}
+      </CounterStateContext.Provider>
+    </CounterDispatchContext.Provider>
+  );
+};
+
+export const useCount = () => useContext(CounterStateContext);
+export const useDispatchCount = () => useContext(CounterDispatchContext);

examples/with-context-api/app/about/page.tsx

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+"use client";
+
+import type { MouseEvent } from "react";
+import Link from "next/link";
+import { useCount, useDispatchCount } from "@/_components/Counter";
+
+export default function About() {
+  const count = useCount();
+  const dispatch = useDispatchCount();
+
+  const handleIncrease = (event: MouseEvent<HTMLButtonElement>) =>
+    dispatch({
+      type: "INCREASE",
+    });
+  const handleIncrease15 = (event: MouseEvent<HTMLButtonElement>) =>
+    dispatch({
+      type: "INCREASE_BY",
+      payload: 15,
+    });
+
+  return (
+    <>
+      <h1>ABOUT</h1>
+      <p>Counter: {count}</p>
+      <button onClick={handleIncrease}>Increase</button>
+      <button onClick={handleIncrease15}>Increase By 15</button>
+      <p>
+        <Link href="/">Home</Link>
+      </p>
+    </>
+  );
+}

examples/with-context-api/app/layout.tsx

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+import type { Metadata } from "next";
+import { CounterProvider } from "@/_components/Counter";
+
+export const metadata: Metadata = {
+  title: "Next.js",
+  description: "Generated by Next.js",
+};
+
+export default function RootLayout({
+  children,
+}: Readonly<{
+  children: React.ReactNode;
+}>) {
+  return (
+    <html lang="en">
+      <body>
+        <CounterProvider>{children}</CounterProvider>
+      </body>
+    </html>
+  );
+}

examples/with-context-api/app/page.tsx

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+"use client";
+
+import type { MouseEvent } from "react";
+import Link from "next/link";
+import { useCount, useDispatchCount } from "@/_components/Counter";
+
+export default function Home() {
+  const count = useCount();
+  const dispatch = useDispatchCount();
+
+  const handleIncrease = (event: MouseEvent<HTMLButtonElement>) =>
+    dispatch({
+      type: "INCREASE",
+    });
+  const handleDecrease = (event: MouseEvent<HTMLButtonElement>) =>
+    dispatch({
+      type: "DECREASE",
+    });
+
+  return (
+    <>
+      <h1>HOME</h1>
+      <p>Counter: {count}</p>
+      <button onClick={handleIncrease}>Increase</button>
+      <button onClick={handleDecrease}>Decrease</button>
+      <p>
+        <Link href="/about">About</Link>
+      </p>
+    </>
+  );
+}

examples/with-context-api/package.json

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+{
+  "private": true,
+  "scripts": {
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start"
+  },
+  "dependencies": {
+    "next": "latest",
+    "react": "^18.3.1",
+    "react-dom": "^18.3.1"
+  },
+  "devDependencies": {
+    "@types/node": "^22.10.1",
+    "@types/react": "^18.3.12",
+    "typescript": "^5.7.2"
+  }
+}

examples/with-context-api/tsconfig.json

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+{
+  "compilerOptions": {
+    "target": "ES2017",
+    "lib": ["dom", "dom.iterable", "esnext"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "react-jsx",
+    "incremental": true,
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ],
+    "paths": {
+      "@/*": ["./*"]
+    }
+  },
+  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
+  "exclude": ["node_modules"]
+}