Functions

Functions are Objects

• In JavaScript functions are objects

function multiply(a, b) {
	return a * b;
}
console.log(multiply.name);
console.log(multiply.toString());
console.log(multiply.constructor);

Function Constructor

• When you declare a function JavaScript engine will use function constructor to create the object.

Example-1

function multiply(a, b) {
	return a * b;
}

const multiply = new Function("a", "b", "return a * b");

Example-2

function Circle(radius) {
    this.radius = radius;
    this.draw = function() {
        console.log("draw");
    }
}

const Circle = new Function("radius", `this.radius = radius;
this.draw = function() {
    console.log("draw");
}`)

call, apply, bind

• call, apply, and bind are JavaScript methods that allow a single function to be used on multiple objects.
• Every time a function is called in JavaScript, it looks for its execution context. Javascript’s this keyword points to and returns that execution context.

References: https://betterprogramming.pub/how-and-why-to-use-call-apply-and-bind-in-javascript-17d50d5a1eb0