how to create a class in js code example

Example 1: create element javascript with class

// create div element by javascript with class

var div = document.createElement('div');
div.className = "div1";

Example 2: javascript class

class ClassMates{
	constructor(name,age){
    	this.name=name;
      	this.age=age;
    }
  	displayInfo(){
    	return this.name + "is " + this.age + " years old!";
    }
}

let classmate = new ClassMates("Mike Will",15);
classmate.displayInfo();  // result: Mike Will is 15 years old!

Example 3: javascript class

// Improved formatting of Spotted Tailed Quoll's answer
class Person {
	constructor(name, age) {
		this.name = name;
		this.age = age;
	}
	introduction() {
		return `My name is ${name} and I am ${age} years old!`;
	}
}

let john = new Person("John Smith", 18);
console.log(john.introduction());

Example 4: javascript classes

class Rectangle {
  constructor(height, width) {
    this.height = height;
    this.width = width;
  }
  // Getter
  get area() {
    return this.calcArea();
  }
  // Method
  calcArea() {
    return this.height * this.width;
  }
}

const square = new Rectangle(10, 10);

console.log(square.area); // 100

Example 5: javascript class example

// to create a class named 'LoremIpsum':

class LoremIpsum {
  
  // a function that will be called on each instance of the class
  // the parameters are the ones passed in the instantiation

  constructor(a, b, c) {
    this.propertyA = a;
    
    // you can define default values that way
    this.propertyB = b || "a default value";
    this.propertyC = c || "another default value";
  }
  
  // a function that can influence the object properties
  
  someMethod (d) {
    this.propertyA = this.propertyB;
    this.propertyB = d;
  }
}






// you can then call it
var loremIpsum = new LoremIpsum ("dolor", null, "sed");

// at this point:
// loremIpsum = { propertyA: 'dolor',
//                propertyB: 'a default value',
//                propertyC: 'sed' }

loremIpsum.someMethod("amit");

// at this point:
// loremIpsum = { propertyA: 'a default value',
//                propertyB: 'amit',
//                propertyC: 'sed' }







.

Example 6: javascript classes

let Person = class {
  constructor(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }
}