access data inside of class javascript code example

Example 1: es6 class example

class Polygon { 
   constructor(height, width) { 
      this.height = height; 
      this.width = width; 
   } 
}

Example 2: es6 class example

var Polygon = class { 
   constructor(height, width) { 
      this.height = height; 
      this.width = width; 
   } 
}

Example 3: javascript classes

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