JavaScript equality between objects and strings

Question

According to Firebug console, we have the following in JavaScript:

>>> [''] == ''
true
>>> [''] == ['']
false

Finding Python to be much more logical here, I'd expect it to be the way round. Anyway, I can understand the second one — apparently two different objects never compare equal to each other, — but what is the reason for the first to give true? What string would ['', ''] compare equal to?

Answer 1

It's comparing the string representation of the array on the left to the string on the right.

alert(['', ''] == ','); // true

alert([1, 2] == '1,2'); // true

Of course you can use the strict comparison operator to avoid this...

alert([''] === ''); // false