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
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Custom Elements (Web Components)
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Shadow Root (Shadow DOM)
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Declarative Shadow DOM
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Mutation Observer
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Tree Walker
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Fetch
And much more..
This repository is a Monorepo. Each package lives under packages/<package>.
This package contains the core functionality of Happy DOM.
This package makes it possible to use Happy DOM with Jest.
A utility that registers Happy DOM globally, which makes it possible to use Happy DOM for testing in a Node environment.
This package has been deprecated.
Happy DOM now supports Declarative Shadow DOM which can be used for server-side rendering of web components.
| 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 |