How do I create a GUID or UUID?

⬅️ Web Development 🔗 Stack Overflow

• UUIDs (Universally Unique IDentifier), also known as GUIDs (Globally Unique IDentifier), according to RFC 4122, are identifiers designed to provide certain uniqueness guarantees.

• UUIDS, are 128 bit numbers, composed of 16 octets and represented as 32 base-16 characters, that can be used to identify information across a computer system

• It’s a 36-character alphanumeric string that can be used to identify information

• crypto.randomUUID() is now standard on all modern browsers and JS runtimes. However, because new browser APIs are restricted to secure contexts, this method is only available to pages served locally (localhost or 127.0.0.1) or over HTTPS.

• for generating UUIDs on legacy platforms or in non-secure contexts, there is the uuid module. It is well-tested and supported.

If everything else fails, then use this one

function uuidv4() {
  return "10000000-1000-4000-8000-100000000000".replace(/[018]/g, c =>
    (+c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> +c / 4).toString(16)
  );
}
 
console.log(uuidv4());

Note: solutions based on Math.random() do not provide good uniqueness guarantees.

Uuid Format

• UUIDs must be of the form “xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx”, where x is one of [0-9, a-f] M is one of [1-5], and N is [8, 9, a, or b]