Callbacks and Higher-Order Functions

A function that calls itself
A function passed into another function as an argument, which is then invoked inside the outer function
A callback function is a function passed into another function as an argument, which is then invoked inside the outer function to complete some kind of routine or action. This is a fundamental concept in JavaScript, especially for asynchronous operations. Callbacks allow you to handle the results of an operation after it completes, rather than blocking execution until it finishes.
A function that returns another function
A function that catches errors in other functions