Javascript - deepEqual Comparison

Question

Question (From Eloquent Javascript 2nd Edition, Chapter 4, Exercise 4):

Write a function, deepEqual, that takes two values and returns true only if th

Answer 1

Feel that this version is a bit more readable (easier to comprehend). The logic is very similar with the top answer though. (ES6 this time)

function deepEqual(obj1, obj2) {

    if(obj1 === obj2) // it's just the same object. No need to compare.
        return true;

    if(isPrimitive(obj1) && isPrimitive(obj2)) // compare primitives
        return obj1 === obj2;

    if(Object.keys(obj1).length !== Object.keys(obj2).length)
        return false;

    // compare objects with same number of keys
    for(let key in obj1)
    {
        if(!(key in obj2)) return false; //other object doesn't have this prop
        if(!deepEqual(obj1[key], obj2[key])) return false;
    }

    return true;
}

//check if value is primitive
function isPrimitive(obj)
{
    return (obj !== Object(obj));
}

By the way, there is a cheater version of deep equal which works like a charm)) However, it's approximately 1.6 times slower.

As noticed by zero298, this approach is sensitive to the properties ordering and shouldn't be taken seriously

function cheatDeepEqual(obj1, obj2)
{
    return JSON.stringify(obj1) === JSON.stringify(obj2);
}