Lee Machin

"Don't alter your history once it's published."

I think you're alright to do this if you're working in your own feature branch and are, say, tidying up a pull request you've been working on after making further changes.

When using a for loop you'd probably cache the length inline and do this:

for (var i = 0, l = ary.length; i < l; i++) {
  ...
}

http://pryrepl.org/ - Pry allows you to drop into a full on REPL - inside the scope it was invoked in - during your tests by using binding.pry instead of debugger.

Ah, this is good to know! Shame MySQL doesn't have it.

Don't overuse $(this), but do understand this and what it scopes to when you do use it :)