what is constructors in javascript code example

Example 1: 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 2: constructors javascript

function Bird() {
  this.name = "Albert";
  this.color = "blue";
  this.numLegs = 2;
}
/*
This constructor defines a Bird object with properties name, color, and
numLegs set to Albert, blue, and 2, respectively.
Constructors follow a few conventions:
-Constructors are defined with a capitalized name to distinguish them from
other functions that are not constructors.

-Constructors use the keyword this to set properties of the object they will
create. Inside the constructor, this refers to the new object it will create.

-Constructors define properties and behaviors instead of returning a value as
other functions might.
*/