cometkim / happy-dom

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. It includes many web standards from WHATWG DOM and HTML.

About

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. It includes many web standards from WHATWG DOM and HTML.

The goal of Happy DOM is to emulate enough of a web browser to be useful for testing, scraping web sites and server-side rendering.

Happy DOM focuses heavily on performance and can be used as an alternative to JSDOM.

Read more about how to use Happy DOM

DOM Features

• Custom Elements (Web Components)

• Shadow Root (Shadow DOM)

• Declarative Shadow DOM

• Mutation Observer

• Tree Walker

• Fetch

And much more..

Works With

• Google LitHTML

• Google LitElement

• React

• Angular

• Vue

Packages

This repository is a Monorepo. Each package lives under packages/<package>.

happy-dom

This package contains the core functionality of Happy DOM.

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jest-environment

This package makes it possible to use Happy DOM with Jest.

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global-registrator

A utility that registers Happy DOM globally, which makes it possible to use Happy DOM for testing in a Node environment.

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server-rendering

This package has been deprecated.

Happy DOM now supports Declarative Shadow DOM which can be used for server-side rendering of web components.

Performance

Operation	JSDOM	Happy DOM
Import / Require	333 ms	45 ms
Parse HTML	256 ms	26 ms
Serialize HTML	65 ms	8 ms
Render custom element	214 ms	19 ms
querySelectorAll('tagname')	4.9 ms	0.7 ms
querySelectorAll('.class')	6.4 ms	3.7 ms
querySelectorAll('[attribute]')	4.0 ms	1.7 ms
querySelectorAll('[class~="name"]')	5.5 ms	2.9 ms
querySelectorAll(':nth-child(2n+1)')	10.4 ms	3.8 ms

See how the test was done here

Contributing

Read more about how to develop and contribute