 3/28/2013 - 12:45 PM

``````{
"name": "UUID",

"description": "Generates random UUIDs",

"keywords": [
"UUID",
"ID",
"random"
]
}``````
``a=(function(c,b,e){c=[],b=function(a){return a?(a^Math.random()*16>>a/4).toString(16):([1e7]+-1e3+-4e3+-8e3+-1e11).replace(//g,b)};return function(){while(~c.indexOf(e=b()));return c.push(e),e}}())``
``````a = function(c,b,e){
c=[],                // list of known uuids
b=function(
a                  // placeholder
){
return a           // if the placeholder was passed, return
? (              // a random number from 0 to 15
a ^            // unless b is 8,
Math.random()  // in which case
* 16           // a random number from
>> a/4         // 8 to 11
: (              // or otherwise a concatenated string:
[1e7] +        // 10000000 +
-1e3 +         // -1000 +
-4e3 +         // -4000 +
-8e3 +         // -80000000 +
-1e11          // -100000000000,
).replace(     // replacing
//g,    // zeroes, ones, and eights with
b            // random hex digits
)
};
return function(){
while(
~c.indexOf(e=b())// create uuids which are not in the list of known ids yet
);
return c.push(e),e;// push the new id in array of known ids and return it
}
}())``````

# UUID

Returns a random v4 UUID of the form `xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx`, where each `x` is replaced with a random hexadecimal digit from 0 to f, and `y` is replaced with a random hexadecimal digit from 8 to b.

There's also @LeverOne's approach using iteration, which is one byte shorter.

``````            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
Version 2, December 2004

Copyright (C) 2011 Jed Schmidt <http://jed.is>

Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.

DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

0. You just DO WHAT THE FUCK YOU WANT TO.``````