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JavaScript

Callbacks in JavaScript

Introduction to JavaScript
What is JavaScript? How it works? History of JavaScript
Basic Concepts in JavaScript
Variables Data Types Operators Control Flow
Functions and Data Structures
Functions Builtin functions Userdefined functions Parameters and Arguments Arrays Indexes and length Array methods
ObjectOriented JavaScript
Object and Properties Constructors Inheritance Prototype
DOM Manipulation
What is DOM? Accessing HTML elements with JavaScript Manipulating HTML elements with JavaScript Events and event handling
Asynchronous JavaScript
Callbacks Promises Async/await Asynchronous data loading AJAX
jQuery
What is jQuery? Selecting and manipulating HTML elements with jQuery jQuery events
Browser APIs
Working with Web Storage Location API Navigator API Geolocation API Canvas API
Expressions and Regular Expressions
Boolean expressions Regular expressions
Debugging and Testing JavaScript
Debugging basics Chrome Developer Tools Unit testing Testing frameworks
JavaScript Libraries and Frameworks
Introduction to libraries and frameworks React.js Angular.js Vue.js Node.js
Deploying JavaScript Applications
Deploying for the Web Hosting options
Ecmascript6 Features
Classes Arrow functions Promises Destructuring of Objects and Arrays Default parameters and Spread Operator
Security and Best Practices in JavaScript
Security basics Best practices for writing safe and maintainable JavaScript code Code optimization techniques
Conclusion
Recap of the course Next Steps.

Callbacks

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#description

In JavaScript, a callback is a function that is passed as an argument to another function and is executed after some operation has been completed. The function that accepts the callback is responsible for calling it at the appropriate time.

Callbacks are commonly used in asynchronous programming, where a function does not immediately return a result but instead relies on a callback to handle the result once it is available. For example, when making an AJAX request to a server, a callback function is passed as an argument to the AJAX function, and is executed once the request has been completed and the response has been received.

Here's an example:

 
                    
function getData(callback) {
  setTimeout(function() {
    const data = [1, 2, 3, 4, 5];
    callback(data);
  }, 1000);
}

getData(function(data) {
  console.log(data);
});

In this example, the getData function accepts a callback as an argument, which is executed after a 1-second delay. The callback function receives an array of data, which is then printed to the console.

Callbacks are a fundamental concept in JavaScript and are used heavily in many frameworks and libraries. Learning how to use them effectively is essential for writing efficient and scalable JavaScript code.

March 25, 2023

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