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Constructors 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.

Constructors

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In JavaScript, constructors are special functions that are used to create objects. They help define the structure and behavior of an object. A constructor function is called when a new object is created with the keyword new.

Here's an example of a constructor function:

 
                    
function Person(name, age) {
  this.name = name;
  this.age = age;
}

var john = new Person("John", 25);

In this example, Person is a constructor function that takes two parameters, name and age. The this keyword refers to the object being created and sets the name and age properties of that object.

When we call new Person("John", 25), JavaScript creates a new object and assigns it to the john variable. The Person constructor is called with the arguments "John" and 25, and the name and age properties of the john object are set accordingly.

Constructors can also define methods for the objects they create.

Here's an example:

 
                    
function Person(name, age) {
  this.name = name;
  this.age = age;
  
  this.sayHello = function() {
    console.log("Hello, my name is " + this.name);
  }
}

var john = new Person("John", 25);
john.sayHello(); // prints "Hello, my name is John"

In this example, we've added a sayHello method to the Person constructor. This method is defined inside the constructor function and is called like any other method on the object.

Constructors are a powerful tool in JavaScript because they allow us to create complex objects with behavior that's specific to the object's purpose.

March 25, 2023

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