Table of Content
- Introduction
- What is the Callback function?
- Purpose of using the Callback function?
- Benefits of using Callback function
Introduction
In this article we discuss what is Callback function is and its Benefits. You want to make your function run after another function get completed automatically so you can use the callback function. By using callback functions we can able to avoid many errors.
What is the Callback function?
The function passed into another function as an argument, then it is invoked inside the outer function to complete some kind of routine or action.
Example:
// function
function paritech(name, callback){
console.log(Hi' + ' ' + name);
callback();
}
// callback function
function callMe() {
console.log('I am callback function');
}
// passing function as an argument
paritech('AchieversIT', callMe);
Output:
Hi AchieversIT
I am callback function
Purpose of using the Callback function?
Javascript runs code in a top-down approach. Even Though there are some cases that have to execute the code after something happens also not sequentially. That is known as Asynchronous programming. CallBacks are mostly used in arrays, timer functions, event handlers, etc.
CallBack function using Timer:
function paritech() {
console.log('Hello world');
}
function sayName(name) {
console.log('Hello' + ' ' + name);
}
// calling the function
setTimeout(paritech, 2000);
sayName('John');
Output:
Hello John
Hello world
Explanation of this example
First we call the sayName function so, It prints (Hello John) and after 2 seconds greet functions will call, it prints the output as Hello World.
CallBack function using Array:
function CheckDatatype_Every(arr, sDatatype) {
for(var k = 0; k < arr.length; k ++)
{
if(typeof(arr[k]) !== sDatatype)
{
return false;
}
}
}
CheckDatatype_Every(["Achievers",IT", “TrainingCenter"],"string");
CheckDatatype_Every(["Pari", "Tech", "SoftSolution"],"string");
Output:
true
false
Benefits of using Callback function:
-
It will make it easier to call the function one after another.
- It keeps us safe from problems and errors.
