Callback Functions Courses

Advanced WordPress: Action and Filter Hooks (2017)
LinkedIn Learning

WordPress: Action and Filter Hooks
LinkedIn Learning

Practice forEach in JavaScript Course (How To)
Treehouse

Callback Functions in JavaScript Course (How To)
Treehouse

Asynchronous JavaScript Tutorial
YouTube

Asynchronous JavaScript - 2020 Version
Net Ninja via YouTube

Creating Asynchronous TypeScript Code
Pluralsight