react-reddit-client | A simple Reddit client written with React.js | REST library

this is using the JSONP API - which essentially requires the API to wrap the JSON into a function callback

eg { "foo": "bar" } with callback=foo would call a global function called foo and pass the JSON as an object.

in this case, it registers window['fn' + Date.now()] as the callback. once the API calls it, it sets state and deletes the global function.

see What is JSONP all about?

TLDR: JSONP needs a global function on the window object. when called, it sets state and removes itself and the script tag. JSONP is useful to circumvent CORS