Callback Functions

An anonymous function can be assigned to a variable.

And hence, like any data assigned to a variable, a function can also be passed as an argument to other functions. Such a function is known as a callback function.

Below we give an example of a function called irrational() that accepts a function as its parameter, and executes it

				
				function irrational(f) {
					console.log(f());
				}
				
			

We declare another function called pi() that returns the value of π

				
				function pi() {
					return Math.PI;
				}
				
			

and pass it as an argument to irrational()

				
				irrational(pi);
				
			

The function irrational() executes it and prints the value 3.141592653589793 in the console. Here, pi() is a callback function.

					
					irrational(function(){
						return Math.PI;
					});