Javascript string to Guid

Cleanest way?

Shortest:

var txt = shift.employee.id;
txt.replace(/([0-z]{8})([0-z]{4})([0-z]{4})([0-z]{4})([0-z]{12})/,"$1-$2-$3-$4-$5");
//"79820548-6e95-4fa8-80a0-b366e6725f71"

or if you don't care about the acceptable characters, it can be be even shorter (and cleaner):

txt.replace(/(.{8})(.{4})(.{4})(.{4})(.{12})/,"$1-$2-$3-$4-$5");  //boom!

Some don't like using regex for everything, but I liked it.

You could use an regular expression:

var rxGetGuidGroups = /(\w{8})(\w{4})(\w{4})(\w{4})(\w{12})/,
    employeeId = shift.employee.id.replace(rxGetGuidGroups, '$1-$2-$3-$4-$5');

jsFiddle

I did it in string manipulation

var str = "798205486e954fa880a0b366e6725f71";
var parts = [];
parts.push(str.slice(0,8));
parts.push(str.slice(8,12));
parts.push(str.slice(12,16));
parts.push(str.slice(16,20));
parts.push(str.slice(20,32));
var GUID = parts.join('-'); 

console.log(GUID) // prints expected GUID

I did it this way because I don't like inserting characters between strings. If there is any problem tell me.

Or you could use a for loop like bellow

var str = "798205486e954fa880a0b366e6725f71";
var lengths = [8,4,4,4,12];
var parts = [];
var range = 0; 
for (var i = 0; i < lengths.length; i++) {
    parts.push(str.slice(range,range+lengths[i]));
    range += lengths[i];
};
var GUID = parts.join('-');
console.log(GUID);