What are the best practices for using Playwright?

Playwright is a Node.js library to automate Chromium, Firefox, and WebKit browsers with a single API. Playwright is designed to enable cross-browser web automation that is ever-green, capable, reliable, and fast. Here are some best practices when using Playwright:

1. Use async/await:

Playwright operations are asynchronous by nature, so using async/await syntax is a best practice. This allows you to write cleaner, more understandable code.

const playwright = require('playwright');

(async () => {
  const browser = await playwright.chromium.launch();
  const context = await browser.newContext();
  const page = await context.newPage();
  await page.goto('https://example.com');
  //...
  await browser.close();
})();

2. Use selectors:

Playwright provides a powerful selector engine that allows you to select elements on the page in a variety of ways. This can make your scripts more resilient to changes in the UI.

await page.click('text="Sign in"'); // clicks an element with "Sign in" text
await page.fill('input[name="username"]', 'John Doe'); // fills an input with name "username"

3. Use auto-waiting:

One of the unique features of Playwright is its auto-waiting mechanism. When you perform an action (like clicking a button or navigating to a page), Playwright automatically waits for the action to complete before moving on. This eliminates the need for manual sleep statements or polling loops.

await page.click('#submit-button'); // Playwright waits for the click action to complete
await page.waitForNavigation(); // waits for navigation to complete

4. Set up and tear down properly:

In your scripts, you should always set up your browser, context, and pages correctly, and make sure to close them when you're done. This helps prevent memory leaks and ensures your scripts run reliably.

const browser = await playwright.chromium.launch();
const context = await browser.newContext();
const page = await context.newPage();

// ... do work ...

await page.close();
await context.close();
await browser.close();

5. Handle errors:

Make sure to handle errors in your scripts. This can help you debug issues and prevent your script from crashing unexpectedly.

try {
  await page.goto('https://example.com');
} catch (error) {
  console.error('Failed to navigate:', error);
}

6. Use the Playwright test runner:

Playwright comes with its own test runner, playwright test, which provides features like parallel test execution, retries, and snapshot testing. It's a best practice to use this test runner for your Playwright scripts.

npx playwright test

7. Leverage browser contexts:

Browser contexts are isolated environments that can be used to simulate multiple users or sessions. Leveraging browser contexts can make your scripts more efficient and flexible.

const context1 = await browser.newContext();
const context2 = await browser.newContext();

// You can use these two contexts independently

Remember, these are just best practices. Depending on your specific use case, there may be other strategies that work better for you.