Standalone UUID generator in Javascript

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Standalone UUID generator in Javascript

12 June 2020 (Updated: 15 June 2020)

Here is a simple and easy (no external dependencies) method to generate UUID in your Javascript applications.

// Author: Abhishek Dutta, 12 June 2020
// License: CC0 (https://creativecommons.org/choose/zero/)
function uuid() {
  var temp_url = URL.createObjectURL(new Blob());
  var uuid = temp_url.toString();
  URL.revokeObjectURL(temp_url);
  return uuid.substr(uuid.lastIndexOf('/') + 1); // remove prefix (e.g. blob:null/, blob:www.test.com/, ...)
}

The URL.createObjectURL() static method available in Javascript creates a unique URL to represent an object passed to it as a parameter. The uuid() method uses this property of URL.createObjectURL() to generate unique URL -- which is a random UUID in all the browsers that I have tested so far -- on empty objects. Here are some example UUID generated by this method:

for(var i=0; i<10; ++i) { console.log(uuid()); }

f6ca05c0-fad5-46fc-a237-a8e930e7cb49
6a88664e-51e1-48c3-a85e-7bf00467e9e6
e6050f4c-e86d-4081-9376-099bfbef2c30
bde3da3c-b318-4498-8a03-9a773afa84bd
ba0fda03-f806-4c2f-b6f5-1e74a299e603
62b2edc3-b09f-4bf9-8dbf-c4d599479a29
e70c0609-22ad-4493-abcc-0e3445291397
920255b2-1838-497d-bc33-56550842b378
45559c64-971c-4236-9cfc-706048b60e70
4bc4bbb9-1e90-432b-99e8-277b40af92cd

Note: The intended purpose of URL.createObjectURL() is not to generate random UUID. So, the above method of generating UUID may cause side effects that I am not yet aware of. If you can think of any issues, please let me know.

Updates:

• Michael J. R. reported via email that URL.createObjectURL() in Internet Explorer 11 returns a blob URL in the following format blob:f6976204-3976-4208-aadc-c2c4260883f7 and therefore suggested the following update to the uuid() method: return uuid.split(/[:\/]/g).pop().
• one800higgins : this works because generating a UUID for the blob URL is part of the spec.
• DrDuPont: Here's the file API working draft from 2010. The outputted URI was slated to be a UUID from the beginning.