In a custom plugin I made, I had to add a custom media upload button in order to make sure only a single Video file is can be selected.
After doing some research, I discovered the handy & pretty undocumented component: wp.media
Just to make sure we’re on the same page, this is a JavaScript component which is a part of WordPress, used to handle Media upload (when writing a post).
If you're not sure how to add fields/buttons within post editing, take a look at the add_meta_boxes action, just so you can understand the context.
Let’s start with a simple upload button:
In a custom plugin I made, I had to add a custom media upload button in order to make sure only a