use previous launched browser don't launch a new one

To use a previously launched browser instance in Puppeteer, you can connect to an existing instance using the puppeteer.connect() method. Here are the steps to achieve this:

1. Start a new instance of the Chrome browser using Puppeteer by calling the puppeteer.launch() method. This method returns a Promise that resolves to a Browser instance.

   const puppeteer = require('puppeteer');
   
   let browser;
   
   puppeteer.launch().then(function (instance) {
     browser = instance;
   });
   

2. Once the browser instance is launched, you can connect to it from another script or function using the puppeteer.connect() method. This method returns a Promise that resolves to a Browser instance.

   const puppeteer = require('puppeteer');
   
   let browser;
   
   puppeteer.launch().then(function (instance) {
     browser = instance;
   
     // Connect to the existing browser instance
     puppeteer.connect({ browserWSEndpoint: browser.wsEndpoint() }).then(function (browser) {
       // Use the existing browser instance
     });
   });
   

3. In the puppeteer.connect() method, you need to pass the browserWSEndpoint option, which is the WebSocket endpoint of the browser instance. You can get this endpoint by calling the browser.wsEndpoint() method on the original Browser instance.

4. Once you have connected to the existing browser instance, you can use it just like you would use a newly launched browser instance. For example, you can create a new page using the browser.newPage() method, navigate to a URL using the page.goto() method, and interact with the page using the various Puppeteer API methods.

Here's an example that uses the above steps to connect to an existing browser instance and navigate to a website:

const puppeteer = require('puppeteer');

let browser;

puppeteer.launch().then(function (instance) {
  browser = instance;

  // Connect to the existing browser instance
  puppeteer.connect({ browserWSEndpoint: browser.wsEndpoint() }).then(function (browser) {
    // Use the existing browser instance
    browser.newPage().then(function (page) {
      page.goto('https://www.google.com').then(function () {
        console.log('Page navigated to https://www.google.com');
      });
    });
  });
});

In this example, we first launch a new browser instance using puppeteer.launch(). Then, we connect to the existing instance using puppeteer.connect(). Once connected, we create a new page using browser.newPage() and navigate to https://www.google.com using page.goto(). Finally, we log a message to the console to indicate that the page has been navigated to.

To detect if there is a browser instance already launched and reuse it if it exists, you can use the puppeteer.connect() method to establish a connection to an existing browser instance. Here are the steps to achieve this:

1. First, you need to check if there is a browser instance already running. You can do this by trying to connect to an existing instance using the puppeteer.connect() method.

   const puppeteer = require('puppeteer');
   
   let browser;
   
   // Try to connect to an existing browser instance
   puppeteer.connect({ browserWSEndpoint: 'ws://localhost:3000' }).then(function (instance) {
     browser = instance;
   
     // Use the existing browser instance
   }).catch(function () {
     // Launch a new browser instance
     puppeteer.launch().then(function (instance) {
       browser = instance;
   
       // Use the new browser instance
     });
   });
   

2. In the puppeteer.connect() method, you need to pass the browserWSEndpoint option, which is the WebSocket endpoint of the browser instance. You can specify the endpoint of the existing instance that you want to connect to. If there is no existing instance running, this method will throw an error.

3. If the puppeteer.connect() method throws an error, you can assume that there is no existing instance and launch a new one using the puppeteer.launch() method.

4. Once you have either connected to an existing browser instance or launched a new one, you can use it just like you would use a newly launched browser instance. For example, you can create a new page using the browser.newPage() method, navigate to a URL using the page.goto() method, and interact with the page using the various Puppeteer API methods.

Here's an example that uses the above steps to detect if there is a browser instance already launched and reuse it if it exists:

const puppeteer = require('puppeteer');

let browser;

// Try to connect to an existing browser instance
puppeteer.connect({ browserWSEndpoint: 'ws://localhost:3000' }).then(function (instance) {
  browser = instance;

  // Use the existing browser instance
  browser.newPage().then(function (page) {
    page.goto('https://www.google.com').then(function () {
      console.log('Page navigated to https://www.google.com');
    });
  });
}).catch(function () {
  // Launch a new browser instance
  puppeteer.launch().then(function (instance) {
    browser = instance;

    // Use the new browser instance
    browser.newPage().then(function (page) {
      page.goto('https://www.google.com').then(function () {
        console.log('Page navigated to https://www.google.com');
      });
    });
  });
});

In this example, we first try to connect to an existing browser instance using puppeteer.connect(). If this method throws an error, we assume that there is no existing instance and launch a new one using puppeteer.launch(). Once we have either connected to an existing instance or launched a new one, we create a new page using browser.newPage() and navigate to https://www.google.com using page.goto(). Finally, we log a message to the console to indicate that the page has been navigated to.