contructor javascript code example

Example 1: metodo constructor javascript

//CREAR UNA CLASE
class miClase {
    constructor(primero, segundo) {
        this.uno = primero;
        this.dos = segundo;
        this.tres = "Hola a todos";
    };
    miMetodoUno() {
        return this.dos;
    }
    miMetodoDos(parametroUno, parametroDos) {
        console.log(
            "El parametro UNO es: " + parametroUno +
            "<br>El parametro DOS es: " + parametroDos
        )
    }
}
//CREAR UN OBJETO - instanciar
var objetoUno = new miClase("Antonio", 56);
//RECUPERAR DATOS
objetoUno.miMetodoDos("Manuel", 44);

Example 2: constructor in js

A constructor is a function that creates an instance of a class
  which is typically called an “object”. In JavaScript, a constructor gets 
  called when you declare an object using the new keyword.
  The purpose of a constructor is to create an object and set values if 
  there are any object properties present.

Example 3: why do we use Object Constructors

function Tree(name) {
  this.name = name
}

let theTree = new Tree('Redwood')
console.log('theTree.constructor is ' + theTree.constructor)