Callback in JavaScript
Callback is also called the higher order function in javaScript.
A callback function is a function passed into another function as an argument, which is then invoked inside the outer function to complete some kind of routine or action.
function greeting(name) {
alert('Hello ' + name);
}
function processUserInput(callback) {
var name = prompt('Please enter your name.');
callback(name);
}
processUserInput(greeting);
The above example is a synchronous callback, as it is executed immediately.
let x = function(){
console.log("I am called from inside a function");
};
let y = function(callback){
console.log("Do something");
callback();
};
y(x);
Multiple callabcks
let add = function(a,b){
return a+b;
};
let multiply = function(a,b){
return a*b;
};
let substraction = function(a,b){
return a-b;
}
let calculate = function(num1,num2,callback){
return callback(num1,num2);
}
console.log(calculate(5,3,add));
Anonymous callback function
let calculate = function(num1,num2,callback){
return callback(num1,num2);
}
console.log(calculate(5,3,function(a,b){
return a*b;
}));
