Object Comparison

books.js

var assert = require('assert');

class Book{
    constructor(title, author, year, publisher){
        this.title = title;
        this.author = author;
        this.year = year;
        this.publisher = publisher;
    }
}


let book = new Book('The Old Man and the Sea', 'Earnest Hemingway', 1952, "Scribner's Sons");
let sameBook = new Book('The Old Man and the Sea', 'Earnest Hemingway', 1952, "Scribner's Sons");
let cloneBook = book;


describe('Book', function() {
  describe('object comparison', function() {
    it('should return true for comparison', function() {
      assert.equal(book !== sameBook, true, "These books are not the same as their reference is different");
    });

    it('should return true for json stringify comparison', function(){
        assert.equal(JSON.stringify(book)===JSON.stringify(sameBook), true, "These json string literals are not the same.")
    });

    it('should return true for json object comparison', function(){
        assert.equal(cloneBook === book, true); 
    });
    
  });

});

Using the mocha test framework to show the nature of object comparison. Same type of an object does not equate to the same reference. Only the last one is the actual comparison of the same object to object comparison.