Check if you're on a development version or the live version of your site
A tiny script that displays a message if you're on the development version of a site, so you can visually distinguish it from the live version.
is-dev is on npm, so installing it is as easy as doing:
$ npm install --save is-dev
is-dev.js via a script tag, or
require('is-dev') in your script. After that you can call it like this (all options are optional):
IE9 and up (array.map).