What is Playwright and what are its main features?

Playwright is a Node.js library developed by Microsoft and used for controlling web browsers to perform actions like generating screenshots and PDFs of pages, crawling a Single-Page Application (SPA), and automating form submission. It provides a high-level API to control headless (without a user interface) or non-headless browsers.

Playwright supports Chromium, Firefox, and WebKit with a single API, which makes it a powerful tool for cross-browser testing.

Here are some main features of Playwright:

1. Multiple Browser Support: Playwright supports all modern browsers including Chrome, Firefox, and Safari. This allows you to test your web application on all these browsers using a single tool.

2. Headless and Non-Headless Browsers: Playwright can work with both headless and non-headless browsers. This provides the flexibility to visualize the automation process or run it in the background.

3. Network Interception: Playwright allows you to intercept network activity, which can be used to mock network responses or to verify them.

4. Mobile Device Emulation: Playwright supports mobile device emulation which can be used to test your responsive designs.

5. Multi-page support: With Playwright, you can open multiple pages at once and control them independently.

Here's a basic example of using Playwright in JavaScript:

// Import the playwright package
const playwright = require('playwright');

(async () => {
  // Launch a new browser 
  const browser = await playwright.chromium.launch();
  // Create a new browser context
  const context = await browser.newContext();
  // Create a new page
  const page = await context.newPage();
  // Navigate to a URL
  await page.goto('http://example.com');
  // Take a screenshot
  await page.screenshot({ path: 'example.png' });
  // Close the browser
  await browser.close();
})();