Jest Preview

Debug your Jest tests. Effortlessly. 🛠🖼

Try Jest Preview Online. No downloads needed!

Why jest-preview

When writing tests using Jest, we usually debug by reading the HTML code. Sometimes, the HTML is too complicated to visualize the UI in our head. jest-preview initiates a server and serve your HTML in a browser, then you can see your actual UI visually, which helps you debug jest tests faster.

jest-preview is initially designed to work with jest and react-testing-library. The package is framework-agnostic, and you can use it with any testing libraries.

Features

• 👀 Preview your actual app's HTML in a browser in milliseconds.
• 🔄 Auto reload browser when execute preview.debug().
• 💅 Support CSS:
  • ✅ Direct CSS import
  • ✅ Number of CSS-in-JS libraries, such as:
    • ✅ Styled-components
    • ✅ Emotion
  • ✅ External CSS
  • ✅ CSS Modules
  • ✅ Sass
• 🌄 Support viewing images.

How to use jest-preview in 2 lines of code

+import preview from 'jest-preview';

describe('App', () => {
  it('should work as expected', () => {
    render(<App />);
+    preview.debug();
  });
});

Or:

+import { debug } from 'jest-preview';

describe('App', () => {
  it('should work as expected', () => {
    render(<App />);
+    debug();
  });
});

You also need to start the Jest Preview Server by running the CLI jest-preview. Please continue to read Usage for the details instructions.

Examples

• Use with Vite: Example with Vite
• Use with Create React App: Example with CRA
• Use with NextJs Rust Compiler: Example with NextJs Rust Compiler
• Use with NextJS Babel: Example with CRA

Installation

See the Installation Guide on Jest Preview official website.

Usage

See the Usage Guide on Jest Preview official website.

Advanced configurations

Jest Preview comes with Pre-configured transformation. However, in more advanced use cases where you have custom code transformation, check out the Code Transformation Guide.

Upcoming features

• Support more css-in-js libraries.
• Multiple preview.
• You name it.

Support

Please file an issue, or add a new discussion if you encounter any issues.

You can also mention @JestPreview or @hung_dev on twitter if you want to have some more discussions or suggestions.

We also have a Discord server:

Contributing

We can't wait to see your contributions. See the Contribution Guide at CONTRIBUTING.md

Contributors ✨

Thanks goes to these wonderful people (emoji key):

Hung Viet Nguyen 💻 📖 💡	Truong Nguyen 💻 📖 💡	Viet Huu Doan 🎨	HarveyNguyen ⚠️	Matt Murphy 📖	Traitanit Huangsri 💻	Thanh Son Nguyen 💻 💡 📖
Minh Nguyen 📖	Kyle(Tình Vũ) 🐛	Makoto Tateno 📖	Abhishek Rawat 📖	Huynh Duc Duy 💻	Nuno Casteleira 🐛	sundaycrafts 💻
LunduoCai 🐛	huyenuet ⚠️

This project follows the all-contributors specification. Contributions of any kind welcome!

Star history

License

MIT

Sponsors

If you like the project and want us continue to develop it, please sponsor us via Open Collective, starting from $1.

Bronze Sponsor 🥉 and Silver Sponsor 🥈 on Open Collective will have your logo on README.md and www.jest-preview.com, for the Gold Sponsor 🥇 and Diamond Sponsor 💎, please contact the author.

Bronze Sponsor 🥉