Classes In JavaScript
Classes in JavaScript are a blueprint for creating objects, introduced in ES6. They encapsulate data and behavior by defining properties and methods, enabling object-oriented programming. Classes simplify the creation of objects and inheritance, making code more organized and reusable.
Class In JavaScript
Classes are similar to functions. Here, a class keyword is used instead of a function keyword. Unlike functions classes in JavaScript are not hoisted. The constructor method is used to initialize. The class name is user-defined.
Syntax:
class classname {
constructor(parameter) {
this.classname = parameter;
}
}
Constructor Method
The constructor method in JavaScript is a special method used for initializing objects created with a class.
It’s called automatically when a new instance of the class is created. It typically assigns initial values to object properties using parameters passed to it. This ensures objects are properly initialized upon creation.
Syntax:
class ClassName {
constructor() { ... }
method() { ... }
}
Example 1: The below example illustrates the JavaScript classes.
class emp {
constructor(name, age) {
this.name = name;
this.age = age;
}
}
const emp1 = new emp("Geek1", "25 years");
console.log(emp1.name);
console.log(emp1.age);
Output
Geek1 25 years
Example 2: This example demonstrates the use of constructor to create class in JavaScript.
class Person {
constructor(name, age) {
this.name = name;
this.age = age;
}
}
const person1 = new Person("Alice", 30);
console.log(person1.name); // Output: Alice
console.log(person1.age); // Output: 30
const person2 = new Person("Bob", 25);
console.log(person2.name); // Output: Bob
console.log(person2.age); // Output: 25
Output
Alice 30 Bob 25
Example 3: This example use class to create the object in JavaScript.
class emp {
constructor(name, age) {
this.name = name;
this.age = age;
}
}
const emp1 = new emp("Geek1", "25 years");
const emp2 = new emp("Beginner2", "32 years")
console.log(emp1.name + " : " + emp1.age);
console.log(emp2.name + " : " + emp2.age);
Output
Geek1 : 25 years Beginner2 : 32 years
JavaScript Classes Use-Cases
Classes in JavaScript provide blueprints for creating objects with similar properties and methods. Objects are instances of classes. Classes encapsulate data and behavior, promoting code reusability and organization. Objects created from classes can have unique data but share the same methods defined in the class blueprint.
You can create a JavaScript class by using a predefined keyword named class before the class name.