Add more case functions

[philshafer]

upper-case(), lower-case() and maybe some fancier options in a simple: case() function:

var $x = “tHe eNd”;
case($x, “upper”) == “THE END”
case($x, “lower”) == “the end”
case($x, “cap”) == “The end”
case($x, “caps”) == “The End”
case($x, “camel”) == “theEnd”
case($x, “snake”) == “the_end”