How to call a function that return another function in JavaScript ?

The task is to call a function that returns another function with the help of JavaScript is called a Currying function, a function with numerous arguments that can be converted into a series of nesting functions with the help of the currying method.

We’re going to discuss a few techniques. 

Approach:

• First, call the first function-1.
• Define a function-2 inside function-1.
• Return the call to function-2 from function-1.

Example 1: In this example, “from function 2” is returned from the fun2 which is finally returned by fun1. 

Javascript

function fun1() {
    function fun2() {
        return "From function fun2";
    }
    return fun2();
}

function GFG_Fun() {
    console.log(fun1());
}
GFG_Fun()

Output

From function fun2

Example 2: In this example, “Alert from fun2” is returned from the fun2 along with an alert, Returned value is finally returned by fun1. 

Javascript

function fun1() {
    function fun2() {
        console.log("From function fun2");
        return "Alert from fun2 ";
    }
    return fun2();
}

function GFG_Fun() {
    console.log(fun1());
}
GFG_Fun()

Output

From function fun2
Alert from fun2