JavaScript function return function

JavaScript functions can return another function as its value, which is known as a “higher-order function”. This feature allows for more flexible and powerful code and is commonly used in functional programming to create closures and implement currying.

The syntax for returning a function from another function in JavaScript is as follows:

function outerFunction() {
  // code here
  return function innerFunction() {
    // code here
  };
}

In this syntax, outerFunction is the enclosing function that returns the innerFunction. The innerFunction is defined within the outerFunction and can access its local variables and parameters. When outerFunction is called, it returns the innerFunction as its result.

JavaScript function return function example

Simple example code.

function add(x) {
  return function(y) {
    return x + y;
  }
}

const addTwo = add(2);
console.log(addTwo(3));

Output: 5

Another example

function greetingMaker(name) {
  function greet() {
    console.log(`Hello, ${name}!`);
  }
  return greet;
}

const greetJohn = greetingMaker('John');
greetJohn(); // logs "Hello, John!"

const greetSarah = greetingMaker('Sarah');
greetSarah(); // logs "Hello, Sarah!"

Output:

Or you can do it with the function:

function createCounter() {
  let count = 0;
  return function() {
    count++;
    console.log(count);
  }
}

const counter1 = createCounter();
const counter2 = createCounter();

counter1(); // logs 1
counter1(); // logs 2
counter1(); // logs 3

counter2(); // logs 1
counter2(); // logs 2

Comment if you have any doubts or suggestions on this JS function return topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.

OS: Windows 10

Code: HTML 5 Version