JavaScript test for integer / string

I couldn’t find either of these functions that satisfied my edge cases or desire for simplicity so I wrote/adapted some of my own. Feel free to use, modify, distribute without attribution, but I’d be eternally grateful if you did ;)

The test for integer is adapted from this post, which is actually almost spot on, apart from their is_int([0]) returns true, as does any integer in a string.

I’m pretty sure I’ve seen this test for string a hundred times on the internet and in books. It is by far the most robust:

Please let me know if you can break it!