The OneDrive File Picker is a shared control to facilitate the selection of a files from OneDrive. (This can be consumer OneDrive, OneDrive for Business or SharePoint.) The official documentation is on the Microsoft documentation website.
While working on implementing the JavaScript version, I was stumbling over a few issues. And the documentation seemed to be missing some steps, but I couldn't quite figure out what.
I then came across an article by Ikram Hawramani titled How to get a demo of the OneDrive File Picker JavaScript SDK to work on a local development server. Despite the snarky commentary, the article was very helpful in putting together all the pieces.