Why are objects compared differently?

Question

JavaScript

'use strict';

function A (name, age) {
    this.name = name;
    this.age = age;

    return {
        name: this.name,
        age: this.age,

        toString () {
            return age;
        }
    };
}

function B (name, age) {
    this.name = name;
    this.age = age;

    return {
        name: this.name,
        age: this.age,

        toString () {
            return age;
        }
    };
}

let a = new A("Ben", 30);
let b = new B("Gray", 30);


console.log(a == b); //false
console.log(a >= b); //true

Why is that? How to make sure that the first log was also true?

Answer 1

Because objects are compared by reference, if two references lead to the same object, then you get true, otherwise - false. In order for the first and second cases to be true, the code must be seriously reworked, since it returns {...} each function call creates a new object, and returns. Using this inside functions A and B is not justified, it creates garbage. When comparing >= js tries to bring both operands to a number, and if memory serves, it first looks for the toValueOf method, and if it is not there, it leads to strings using the toString method, in your case there is a toString method, and since objects with the same field values ​​age >= gives true, since toString is implicitly called from objects.