Callback functions are derived from a programming paradigm known as functional programming. At a fundamental level, functional programming specifies the use of functions as arguments. Functional programming was—and still is, though to a much lesser extent today—seen as an esoteric technique of specially trained, master programmers.
- For asynchronous execution (such as reading files, and making HTTP requests)
- In Event Listeners/Handlers
- In setTimeout and setInterval methods
- For Generalization: code conciseness