Josh Comeau does a great job with beginner-friendly explanations of important concepts, and Promises From The Ground Up is no exception. In a nutshell, we have Promises because we need callbacks. We need callbacks because JavaScript is single-threaded and can’t wait around for things. And so we dance. These days, you’ll see more async and await, but it’s just what they call “syntactic sugar” over Promises, which is to say, a cleaner way to write the same code.
Will Sentance goes deep into Promises in JavaScript: The Hard Parts when you’re ready.
