[Examples] Add pagination JS CommonJS Node example

Author: sebastianquek

examples/node/pagination_js_commonjs/.env.example

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+API_KEY=YOUR_API_KEY

examples/node/pagination_js_commonjs/README.md

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+# Node.js pagination JavaScript (CommonJS) example
+
+## Usage
+
+1. Build module
+
+```bash
+cd ../../../   # Navigate to the root folder
+deno task npm
+```
+
+2. Setup environment variables
+
+- Duplicate `.env.example` and name it `.env`.
+- Replace `YOUR_API_KEY` with your SerpApi API key.
+
+3. Install dependencies and run example
+
+```bash
+cd examples/node/pagination_js_commonjs
+npm i
+npm start
+```
+
+## Notes
+
+- If you want to run the example without building the module, you can update
+  `package.json` to depend on the published `serpapi` npm module instead:
+  ```json
+  {
+    "dependencies": {
+      "dotenv": "*",
+      "serpapi": "*" // Relies on the npm module
+    },
+    "scripts": {
+      "start": "node example.js"
+    }
+  }
+  ```

examples/node/pagination_js_commonjs/example.js

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+const Dotenv = require("dotenv");
+const { config, getJson } = require("serpapi");
+
+Dotenv.config();
+const apiKey = process.env.API_KEY;
+
+const extractLinks = (results) => results.map((r) => r.link);
+
+const run = async () => {
+  const params = {
+    q: "Coffee",
+    api_key: apiKey,
+  };
+
+  // Pagination (async/await)
+  let page1 = await getJson("google", params);
+  console.log(
+    "First page links",
+    extractLinks(page1.organic_results),
+  );
+  let page2 = await page1.next?.();
+  console.log(
+    "Second page links",
+    extractLinks(page2?.organic_results),
+  );
+
+  // Pagination (callback)
+  getJson("google", params, (page1) => {
+    console.log(
+      "First page links",
+      extractLinks(page1.organic_results),
+    );
+    page1.next?.((page2) => {
+      console.log(
+        "Second page links",
+        extractLinks(page2.organic_results),
+      );
+    });
+  });
+
+  // Use global config
+  config.api_key = apiKey;
+  page1 = await getJson("google", { q: "Coffee" });
+  page2 = await page1.next?.();
+  console.log(
+    "Second page links",
+    extractLinks(page2?.organic_results),
+  );
+
+  // Pagination loop (async/await)
+  let links = [];
+  let page = await getJson("google", { q: "Coffee" });
+  while (page) {
+    links.push(...extractLinks(page.organic_results));
+    if (links.length >= 30) break;
+    page = await page.next?.();
+  }
+  console.log(links);
+
+  // Pagination loop (callback)
+  links = [];
+  getJson("google", { q: "Coffee" }, (page) => {
+    links.push(...extractLinks(page.organic_results));
+    if (links.length < 30 && page.next) {
+      page.next();
+    } else {
+      console.log(links);
+    }
+  });
+};
+
+run();

examples/node/pagination_js_commonjs/package-lock.json

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+{
+  "dependencies": {
+    "dotenv": "*",
+    "serpapi": "../../../npm"
+  },
+  "scripts": {
+    "start": "node example.js"
+  }
+}