Parsing a little endian hex string to decimal

I have an little endian hex string that needs to be converted to a decimal in JavaScript.

Example hex string: "12AB34CD" To get the correct value it need to swap the bytes to this: "CD34AB12"

Currently I just swap the bytes using substring and then use parseInt().

var string = "12AB34CD";
var parsedInt = parseInt("0x" + string.substring(6,8) + string.substring(4,6)+ string.substring(2,4) + string.substring(0,2);

I have lots of data with unknown lenght to parse, so I was wondering if there is a better way.