Skip to content
JavaScript Book

Practical Higher-Order Functions

A Higher-Order Function (HOF) in JavaScript is a function that does at least one of the following:

  1. Takes one or more functions as arguments (these are often called callback functions).
  2. Returns a function as its result.

This capability is possible because functions in JavaScript are “first-class citizens” – they can be treated like any other value: assigned to variables, passed as arguments, stored in data structures, and returned from other functions.

Higher-order functions are fundamental to functional programming in JavaScript and enable powerful patterns like abstraction, composition, and code reuse.