6 Interesting finding about JavaScript
I found curios things about JavaScript and decided to share.
1. [1,2] + [3,4]?
Yes, “1,23,4”… And that is why — [1,2] + [3,4] = [1,2].toString() + [3,4].toString() OR [1,2].concat([3,4]). So addition of arrays works like addition of strings. This is related link.
2. a = {}; a+a
And the result will be “[object Object][object Object]”, because an object has toString method that by default returns [object Object].
3. {} + 2
Yes, this one also is interesting and the answer is 2.
4. [] + 2
Here the answer is similar and related to the 1st point, which is “2”. Because all concatenations or additions of arrays.
5. {} + []
This one will result in Zero (0), because the first element is an object and not an array (that converted to string).
6. {} + {}
This one will result in NaN.
P.S. Don’t use such question in job interviews :) They are nasty.
