What are higher-order functions in JavaScript?

Question

What are higher-order functions in JavaScript?

Answer

A higher-order function either:

• Takes one or more functions as arguments, or
• Returns a function as a result.

function withLogging(fn) {
  return function (...args) {
    console.log('Calling with args:', args);
    return fn(...args);
  };
}

const add = (a, b) => a + b;
const loggedAdd = withLogging(add);
console.log(loggedAdd(2, 3));

Real-World Example

React’s useEffect, Array.map, and Redux’s connect() are all built on higher-order principles.

Quick Practice

Write a function times(n, fn) that calls fn exactly n times.

Summary

Higher-order functions make code modular, reusable, and expressive.