Understanding React Portals and Its Use-Cases (blog.bitsrc.io)
Nov 05, 2020
React Portal is a first-class way to render child components into a DOM node outside of the parent DOM hierarchy defined by the component tree hierarchy. The Portal's most common use cases are when the child components need to visually break out of the parent container as shown below.
React v16.0 (reactjs.org)
Sep 26, 2017
We’re excited to announce the release of React v16.0! Among the changes are some long-standing feature requests, including fragments, error boundaries, portals, support for custom DOM attributes, improved server-side rendering, and reduced file size.