playwright/docs/src/library-js.md

id	title
library	Playwright Library

Playwright can either be used as a part of the Playwright Test, or as a Playwright Library (this guide). If you are working on an application that utilizes Playwright capabilities or you are using Playwright with another test runner, read on.

• Release notes

Usage

Use npm or Yarn to install Playwright library in your Node.js project. See system requirements.

npm i -D playwright

This single command downloads the Playwright NPM package and browser binaries for Chromium, Firefox and WebKit. To modify this behavior see managing browsers.

Once installed, you can require Playwright in a Node.js script, and launch any of the 3 browsers (chromium, firefox and webkit).

const { chromium } = require('playwright');

(async () => {
  const browser = await chromium.launch();
  // Create pages, interact with UI elements, assert values
  await browser.close();
})();

Playwright APIs are asynchronous and return Promise objects. Our code examples use the async/await pattern to ease readability. The code is wrapped in an unnamed async arrow function which is invoking itself.

(async () => { // Start of async arrow function
  // Function code
  // ...
})(); // End of the function and () to invoke itself

First script

In our first script, we will navigate to whatsmyuseragent.org and take a screenshot in WebKit.

const { webkit } = require('playwright');

(async () => {
  const browser = await webkit.launch();
  const page = await browser.newPage();
  await page.goto('http://whatsmyuseragent.org/');
  await page.screenshot({ path: `example.png` });
  await browser.close();
})();

By default, Playwright runs the browsers in headless mode. To see the browser UI, pass the headless: false flag while launching the browser. You can also use slowMo to slow down execution. Learn more in the debugging tools section.

firefox.launch({ headless: false, slowMo: 50 });

Record scripts

Command Line Interface CLI can be used to record user interactions and generate JavaScript code.

npx playwright codegen wikipedia.org

TypeScript support

Playwright includes built-in support for TypeScript. Type definitions will be imported automatically. It is recommended to use type-checking to improve the IDE experience.

In JavaScript

Add the following to the top of your JavaScript file to get type-checking in VS Code or WebStorm.

//@ts-check
// ...

Alternatively, you can use JSDoc to set types for variables.

/** @type {import('playwright').Page} */
let page;

In TypeScript

TypeScript support will work out-of-the-box. Types can also be imported explicitly.

let page: import('playwright').Page;

System requirements

Playwright requires Node.js version 12 or above. The browser binaries for Chromium, Firefox and WebKit work across the 3 platforms (Windows, macOS, Linux):

Windows

Works with Windows and Windows Subsystem for Linux (WSL).

macOS

Requires 10.14 (Mojave) or above.

Linux

Depending on your Linux distribution, you might need to install additional dependencies to run the browsers.

:::note Only Ubuntu 18.04 and Ubuntu 20.04 are officially supported. :::

See also in the Command Line Interface which has a command to install all necessary dependencies automatically for Ubuntu LTS releases.