playwright/docs/src/puppeteer-js.md
2023-08-21 09:50:22 -07:00

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---
id: puppeteer
title: "Migrating from Puppeteer"
---
<!-- TOC -->
## Migration Principles
This guide describes migration to [Playwright Library](./library) and [Playwright Test](./intro.md) from Puppeteer. The APIs have similarities, but Playwright offers much more possibilities for web testing and cross-browser automation.
- Most Puppeteer APIs can be used as is
- The use of [ElementHandle] is discouraged, use [Locator] objects and web-first assertions instead.
- Playwright is cross-browser
- You probably don't need explicit wait
## Cheat Sheet
| Puppeteer | Playwright Library |
|----------------------------------------------------|---------------------------------------------|
| `await puppeteer.launch()` | `await playwright.chromium.launch()` |
| `puppeteer.launch({product: 'firefox'})` | `await playwright.firefox.launch()` |
| WebKit is not supported by Puppeteer | `await playwright.webkit.launch()` |
| `await browser.createIncognitoBrowserContext(...)` | `await browser.newContext(...)` |
| `await page.setViewport(...)` | `await page.setViewportSize(...)` |
| `await page.waitForXPath(XPathSelector)` | `await page.waitForSelector(XPathSelector)` |
| `await page.waitForNetworkIdle(...)` | `await page.waitForLoadState('networkidle')` |
| `await page.$eval(...)` | [Assertions](./test-assertions) can often be used instead to verify text, attribute, class... |
| `await page.$(...)` | Discouraged, use [Locators](./api/class-locator) instead |
| `await page.$x(xpath_selector)` | Discouraged, use [Locators](./api/class-locator) instead |
| No methods dedicated to checkbox or radio input | `await page.locator(selector).check()`<br/>`await page.locator(selector).uncheck()` |
| `await page.click(selector)` | `await page.locator(selector).click()` |
| `await page.focus(selector)` | `await page.locator(selector).focus()` |
| `await page.hover(selector)` | `await page.locator(selector).hover()` |
| `await page.select(selector, values)` | `await page.locator(selector).selectOption(values)` |
| `await page.tap(selector)` | `await page.locator(selector).tap()` |
| `await page.type(selector, ...)` | `await page.locator(selector).fill(...)` |
| `await page.waitForFileChooser(...)`<br/>`await elementHandle.uploadFile(...)` | `await page.locator(selector).setInputFiles(...)` |
| `await page.cookies([...urls])` | `await browserContext.cookies([urls])` |
| `await page.deleteCookie(...cookies)` | `await browserContext.clearCookies()` |
| `await page.setCookie(...cookies)` | `await browserContext.addCookies(cookies)` |
| `page.on(...)` | `page.on(...)`<br/>In order to intercept and mutate requests, see [`method: Page.route`] |
`page.waitForNavigation` and `page.waitForSelector` remain, but in many cases will not be necessary due to [auto-waiting](./actionability).
The use of [ElementHandle] is discouraged, use [Locator] objects and web-first assertions instead.
Locators are the central piece of Playwright's auto-waiting and retry-ability. Locators are strict. This means that all operations on locators that imply some target DOM element will throw an exception if more than one element matches a given selector.
## Examples
### Automation example
Puppeteer:
```js
const puppeteer = require('puppeteer');
(async () => {
const browser = await puppeteer.launch();
const page = await browser.newPage();
await page.setViewport({ width: 1280, height: 800 });
await page.goto('https://playwright.dev/', {
waitUntil: 'networkidle2',
});
await page.screenshot({ path: 'example.png' });
await browser.close();
})();
```
Line-by-line migration to Playwright:
```js
const { chromium } = require('playwright'); // 1
(async () => {
const browser = await chromium.launch();
const page = await browser.newPage(); // 2
await page.setViewportSize({ width: 1280, height: 800 }); // 3
await page.goto('https://playwright.dev/', {
waitUntil: 'networkidle', // 4
});
await page.screenshot({ path: 'example.png' });
await browser.close();
})();
```
Migration highlights (see inline comments in the Playwright code snippet):
1. Each Playwright Library file has explicit import of `chromium`. Other browsers `webkit` or `firefox` can be used.
1. For browser state isolation, consider [browser contexts](./browser-contexts.md)
1. `setViewport` becomes `setViewportSize`
1. `networkidle2` becomes `networkidle`. Please note that in most cases it is not useful, thanks to auto-waiting.
### Test example
Puppeteer with Jest:
```js
import puppeteer from 'puppeteer';
describe('Playwright homepage', () => {
let browser;
let page;
beforeAll(async () => {
browser = await puppeteer.launch();
page = await browser.newPage();
});
it('contains hero title', async () => {
await page.goto('https://playwright.dev/');
await page.waitForSelector('.hero__title');
const text = await page.$eval('.hero__title', e => e.textContent);
expect(text).toContain('Playwright enables reliable end-to-end testing'); // 5
});
afterAll(() => browser.close());
});
```
Line-by-line migration to Playwright Test:
```js
import { test, expect } from '@playwright/test'; // 1
test.describe('Playwright homepage', () => {
test('contains hero title', async ({ page }) => { // 2, 3
await page.goto('https://playwright.dev/');
const titleLocator = page.locator('.hero__title'); // 4
await expect(titleLocator).toContainText( // 5
'Playwright enables reliable end-to-end testing'
);
});
});
```
1. Each Playwright Test file has explicit import of the `test` and `expect` functions
1. Test function is marked with `async`
1. Playwright Test is given a `page` as one of its parameters. This is one of the many [useful fixtures](./api/class-fixtures) in Playwright Test.
Playwright Test creates an isolated [Page] object for each test. However, if you'd like to reuse a single [Page] object between multiple tests, you can create your own in [`method: Test.beforeAll#1`] and close it in [`method: Test.afterAll#1`].
1. Locator creation with [`method: Page.locator`] is one of the few methods that is sync.
1. Use [assertions](./test-assertions) to verify the state instead of `page.$eval()`.
## Testing
To improve testing, it is advised to use [Locators](./api/class-locator) and web-first [Assertions](./test-assertions). See [Writing Tests](./writing-tests)
It is common with Puppeteer to use `page.evaluate()` or `page.$eval()` to inspect an [ElementHandle] and extract the value of text content, attribute, class... Web-first [Assertions](./test-assertions) offers several matchers for this purpose, it is more reliable and readable.
[Playwright Test](./intro.md) is our first-party recommended test runner to be used with Playwright. It provides several features like Page Object Model, parallelism, fixtures or reporters.
## Playwright Test Super Powers
Once you're on Playwright Test, you get a lot!
- Full zero-configuration TypeScript support
- Run tests across **all web engines** (Chrome, Firefox, Safari) on **any popular operating system** (Windows, macOS, Ubuntu)
- Full support for multiple origins, [(i)frames](./api/class-frame), [tabs and contexts](./pages)
- Run tests in isolation in parallel across multiple browsers
- Built-in test [artifact collection](./test-use-options.md#recording-options)
You also get all these ✨ awesome tools ✨ that come bundled with Playwright Test:
- [Playwright Inspector](./debug.md)
- [Playwright Test Code generation](./codegen-intro.md)
- [Playwright Tracing](./trace-viewer.md) for post-mortem debugging
## Further Reading
Learn more about Playwright Test runner:
- [Getting Started](./intro)
- [Fixtures](./test-fixtures)
- [Locators](./locators.md)
- [Assertions](./test-assertions)
- [Auto-waiting](./actionability)