Major issues

In JS everything are seen as objects. You typeof x to check for object will also return true for functions, arrays etc. And you cant use Object.keys on them.

There are no support for circular references either so you can risk that your code throws.

And if this is strict not loose also note that two objects with different instances are not equal.

[ashaffer]

In JS everything are seen as objects. You typeof x to check for object will also return true for functions, arrays etc. And you cant use Object.keys on them.

This library isn't using any typeof checks...is it? Am I missing something? It's relying on isObject, which checks for 'objectness' like this:

function isObject (val) {
  return !!val && (val.constructor === Object || isObjectString(val.constructor))
}

There are no support for circular references either so you can risk that your code throws.

That's true. Adding support for circular references requires maintaining a reference stack and somewhat substantial increase in complexity. I'm not sure if I want to add that in here or not, it's something to think about though.

And if this is strict not loose also note that two objects with different instances are not equal.

I'm not sure what you mean by this. Can you elaborate?

var a = new String('abc');
var b = new String('abc');

This two looks identical? But they are not and a comparison between them should return false. Different instance. If it should have returned true, you need to compare with same reference:

var a = new String('abc');
eq(a, a,) // true

This for strict mode only, because two object references are different. In the NodeJS core assert module both of this are seen as equal simply because that module is shallow.

You could use getPrototypeOf for this.

I'm experimenting with a similar module as this so you can also see it there with instances.

@ashaffer You see a good example here: https://github.com/zubuzon/kewlr/blob/master/test/specs/objects.ts#L250-L271

[ashaffer]

This two looks identical? But they are not and a comparison between them should return false. Different instance. If it should have returned true, you need to compare with same reference:

I believe this library currently returns false for deepEqual(new String('abc'), new String('abc')). Is that not what you're seeing?