playwright/docs/src/test-typescript-js.md

id	title
test-typescript	TypeScript

Playwright Test supports TypeScript out of the box. You just write tests in TypeScript and Playwright Test will read them, transform to JavaScript and run. This works both with CommonJS modules and ECMAScript modules.

TypeScript with CommonJS

Node.js works with CommonJS modules by default. Unless you use '.mjs' or '.mts' extensions, or specify type: "module" in your pacakge.json, Playwright Test will treat all TypeScript files as CommonJS. You can then import as usual without an extension.

Consider this helper module written in TypeScript:

// helper.ts
export const username = 'John';
export const password = 'secret';

You can import from the helper as usual:

// example.spec.ts
import { test, expect } from '@playwright/test';
import { username, password } from './helper';

test('example', async ({ page }) => {
  await page.locator('#username').fill(username);
  await page.locator('#password').fill(password);
});

TypeScript with ESM

You can opt into using ECMAScript modules by setting type: "module" in your package.json file. Playwright Test will switch to the ESM mode once it reads the playwright.config.ts file, so make sure you have one.

Playwright Test follows the experimental support for ESM in TypeScript and, according to the specification, requires an extension when importing from a module, either '.js' or '.ts'.

First, enable modules in your package.json:

{
  "name": "my-package",
  "version": "1.0.0",
  "type": "module",
}

Then write the helper module in TypeScript as usual:

// helper.ts
export const username = 'John';
export const password = 'secret';

Specify the extension when importing from a module:

// example.spec.ts
import { test, expect } from '@playwright/test';
import { username, password } from './helper.ts';

test('example', async ({ page }) => {
  await page.locator('#username').fill(username);
  await page.locator('#password').fill(password);
});

TypeScript path mapping

If you use path mapping in your tsconfig.json, Playwright Test will pick it up. Make sure that baseUrl is also set.

Here is an example tsconfig.json that works with Playwright Test:

{
  "compilerOptions": {
    "baseUrl": ".", // This must be specified if "paths" is.
    "paths": {
      "@myhelper/*": ["packages/myhelper/*"] // This mapping is relative to "baseUrl".
    }
  }
}

You can now import using the mapped paths:

// example.spec.ts
import { test, expect } from '@playwright/test';
import { username, password } from '@myhelper/credentials';

test('example', async ({ page }) => {
  await page.locator('#username').fill(username);
  await page.locator('#password').fill(password);
});

Manually compile tests with TypeScript

Sometimes, Playwright Test will not be able to transform your TypeScript code correctly, for example when you are using experimental or very recent features of TypeScript, usually configured in tsconfig.json.

In this case, you can perform your own TypeScript compilation before sending the tests to Playwright.

First add a tsconfig.json file inside the tests directory:

{
    "compilerOptions": {
        "target": "ESNext",
        "module": "commonjs",
        "moduleResolution": "Node",
        "sourceMap": true,
        "outDir": "../tests-out",
    }
}

In package.json, add two scripts:

{
  "scripts": {
    "pretest": "tsc --incremental -p tests/tsconfig.json",
    "test": "playwright test -c tests-out"
  }
}

The pretest script runs typescript on the tests. test will run the tests that have been generated to the tests-out directory. The -c argument configures the test runner to look for tests inside the tests-out directory.

Then npm run test will build the tests and run them.