What is shadow DOM? How is it helping Angular 2 to perform better

Shadow DOM is a part of the HTML spec which allows developers to encapsulate their HTML markup, CSS styles and JavaScript. Shadow DOM, along with a few other technologies, gives developers the ability to build their own 1st class tags, web components and APIs just like the <audio> tag. Collectively, these new tags and APIs are referred to as Web Components. Shadow DOM provides better separation of concern along with lesser conflict of styles and scripts with other HTML DOM elements.

Since shadow DOM are static in nature, it’s a good candidate to be cached as it is not accessible to developer. The cached DOM would be rendered faster in the browser providing better performance. Moreover, shadow DOM can be managed comparatively well while detecting the change in angular 2 application and re-paint of view can be managed efficiently.