test-typescript-js.md

id	title
test-typescript	TypeScript

Introduction

Playwright supports TypeScript out of the box. You just write tests in TypeScript, and Playwright will read them, transform to JavaScript and run.

Note that Playwright does not check the types and will run tests even if there are non-critical TypeScript compilation errors. We recommend you run TypeScript compiler alongside Playwright. For example on GitHub actions:

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
    ...
    - name: Run type checks
      run: npx tsc -p tsconfig.json --noEmit
    - name: Run Playwright tests
      run: npx playwright test

For local development, you can run tsc in watch mode like this:

npx tsc -p tsconfig.json --noEmit -w

tsconfig.json

Playwright will pick up tsconfig.json for each source file it loads. Note that Playwright only supports the following tsconfig options: allowJs, baseUrl, paths and references.

We recommend setting up a separate tsconfig.json in the tests directory so that you can change some preferences specifically for the tests. Here is an example directory structure.

src/
    source.ts

tests/
    tsconfig.json  # test-specific tsconfig
    example.spec.ts

tsconfig.json  # generic tsconfig for all typescript sources

playwright.config.ts

tsconfig path mapping

Playwright supports path mapping declared in the tsconfig.json. Make sure that baseUrl is also set.

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

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

You can now import using the mapped paths:

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

test('example', async ({ page }) => {
  await page.getByLabel('User Name').fill(username);
  await page.getByLabel('Password').fill(password);
});

tsconfig resolution

By default, Playwright will look up a closest tsconfig for each imported file by going up the directory structure and looking for tsconfig.json or jsconfig.json. This way, you can create a tests/tsconfig.json file that will be used only for your tests and Playwright will pick it up automatically.

# Playwright will choose tsconfig automatically
npx playwright test

Alternatively, you can specify a single tsconfig file to use in the command line, and Playwright will use it for all imported files, not only test files.

# Pass a specific tsconfig
npx playwright test --tsconfig=tsconfig.test.json

You can specify a single tsconfig file in the config file, that will be used for loading test files, reporters, etc. However, it will not be used while loading the playwright config itself or any files imported from it.

import { defineConfig } from '@playwright/test';

export default defineConfig({
  tsconfig: './tsconfig.test.json',
});

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.