I feel like browser support for position:sticky is now good enough that I no longer plan to polyfill the feature my projects. Feel free to use this, just know that I don't plan on reaching full compatibility with position:sticky.
A position: sticky polyfill that's dependency-free and does not modify the DOM tree, i.e., React-friendly. See react-sticky-position for the React component.
Todo
npm install sticky-position
Released under the MIT License