# jest-metadata 🦸‍♂️ Superhero power for your Jest reporters! 🦸‍♀️ [](https://badge.fury.io/js/jest-metadata)

jest-metadata is a library that allows you to attach user-defined data to any jest-circus entity like describe blocks, function definitions, test runs, invocations, and more. Custom reporters can access your custom data to produce rich and insightful reports leveraging low-level details from jest-circus events and any additional data you want to use in your reports.

🌟 Features

• Attach custom metadata to Jest entities such as describe blocks, function definitions, test runs, and invocations.
• Access your metadata from your reporters to generate insightful reports.
• Graceful degradation for default test environments (node, jsdom) and jest-jasmine2 test runner.
• Custom test environment support via a decorator class.

📚 Guidelines

This library is primarily intended for the authors of custom Jest reporters. Direct usage of jest-metadata in test files is not recommended.

To use jest-metadata, you should:

• Declare jest as a peer dependency (or direct one) in your package.
• Provide your reporter as a class that inherits from jest-metadata/reporter.
• Provide your test environment as a decorator class that can inherit from any WithMetadata(*) class.
• Think about using a namespace for your metadata, so it doesn't clash with other metadata.

The best live example of how to use jest-metadata at the moment is jest-allure2-reporter.

🚀 Quick Start

To get your hands dirty, you can try out jest-metadata directly in your project.

Install jest-metadata using npm:

npm install jest-metadata --save-dev

In your Jest config, add the following:

+  "testEnvironment": "jest-metadata/environment-node",
+  "reporters": [
+    "default",
+    "./your-custom-reporter.js",
+  ],

If you need to use jest-metadata in a JSDOM environment or another custom test environment, please refer to the Integrating jest-metadata into test environment guide.

📖 Usage

In a Test File

Attach metadata to test entities using annotations:

import { metadata, $Set } from 'jest-metadata';

// Write your own DSL for attaching metadata to test entities
// Try to namespace your metadata to avoid collisions with other libraries
const $Description = (text) => $Set('mycompany.description', text);

$Description('This is a sample test suite.');
describe('Login flow', () => {

  $Description('This is a login test.');
  it('should login', () => {
    // ...
    metadata.push('mycompany.attachements', [
      { name: 'screenshot', type: 'image/png', filePath: '/path/to/screenshot.png' },
    ]);
    // ...
  });
});

In a Custom Reporter

Access metadata in a custom Jest reporter:

import { state } from 'jest-metadata';
import { JestMetadataReporter } from 'jest-metadata/reporter';

class CustomReporter extends JestMetadataReporter {
  async onTestCaseResult(test, testCaseResult) {
    await super.onTestCaseResult(test, testCaseResult);

    const metadata = state.getTestFileMetadata(test.path).lastTestEntry;

    const titles = [testCaseResult.title, ...testCaseResult.ancestorTitles.slice().reverse()];
    const descriptions = [metadata, ...metadata.ancestors()].map((m) => m.get('mycompany.description', '')).find(x => x);
    const attachments = [metadata, ...metadata.ancestors()].flatMap((m) => m.get('mycompany.attachements', []));

    const n = titles.length;
    for (let i = n - 1; i >= 0; i--) {
      console.log(`${titles[i]}: ${descriptions[i]}`);
    }
    // Output:
    // > Login flow: This is a sample test suite.
    // > should login: This is a login test.
  }
}

📄 Documentation

For more detailed documentation and examples, see the docs folder.

🌐 Contributing

We welcome contributions from the community! To get involved, please follow these steps:

• Check the GitHub issues for open tasks or submit a new issue if you have a feature request or bug report.
• Fork the repository and create a new branch for your changes.
• Make your changes and submit a pull request.

For more information, see our Contribution Guidelines.

📃 License

This project is licensed under the MIT License.