uuid-with-v6

uuid-with-v6

UUID Version 6 for Node.js

Quickstart

const uuid = require('uuid-with-v6');

console.log(uuid.v6())

API

This module extends uuid and is intended to serve as a drop-in replacement with added "Version 6" functionality.

uuid#v1

See the uuid documentation.

uuid#v4

See the uuid documentation.

uuid#v6

Definition

uuid.v6()

Parameters

None

Returns

A UUIDv6 String.

Example

const uuid = require('uuid-with-v6');

console.log(uuid.v6());
// 1e7126af-f130-6780-adb4-8bbe7368fc2f

uuid#v6setup

Definition

uuid.v6setup([options])

Parameters

options parameters

Parameter	Type	Description	Default
disableRandom	Boolean	Disable the use of UUIDv4 to populate the non-timestamp portion of the identifier	'false'

Returns

A UUIDv6 id generator.

Example

const uuid = require('uuid-with-v6');

const v6 = uuid.v6setup();

console.log(v6());
// 1e7126af-f130-6780-adb4-8bbe7368fc2f

const v6WithMAC = uuid.v6setup({ disableRandom: true });

console.log(v6WithMAC());
// '1e7126cb-6914-60b0-8c07-8a41b327fae3'

Why

Inspired by UUID "Version 6", The version RFC 4122 forgot, this module extends uuid by adding the ability to generate UUIDv6 identifiers.

"Version 6" UUIDs arrange the timestamp from high to low bytes (with some bit-shifting to account for the version parameter) resulting in identifiers where lexicographic sorting yields time-based sorting. The non-timestamp portion of the UUID is filled with random bits (similar to Version 4); consequently, ids generated within the same clock tick are not guaranteed to be lexicographically sorted into time-based order.

Internally, this module implements the "Version 6" specification by first creating a UUIDv1, rearranging the timestamp, then generating eight cryptographically-strong bytes to populate the remaining portion of the identifier. Similar to Version 1, clock sequence and MAC address information can be retained by constructing a UUIDv6 generator with the disableRandom option (see the example below).

UUIDv1 versus UUIDv6

Below are 20 UUIDv1 ids and the corresponding UUIDv6 ids generated at 30 second intervals. Note the critical differences:

• The "high" portion of the timestamp is at the beginning, followed by the "medium" and "low"
• xxxxxxxx-xxxx-1xxx-xxxx-xxxxxxxxxxxx → xxxxxxxx-xxxx-6xxx-xxxx-xxxxxxxxxxxx
• Each identifier ends with cryptographically-strong randomness

UUIDv1                               UUIDv6
------------------------------------ ------------------------------------
5714f720-1268-11e7-a24b-96d95aa38c32 1e712685-714f-6720-a23a-c90103f70be6
68f820c0-1268-11e7-a24b-96d95aa38c32 1e712686-8f82-60c0-ac07-7d6641ed230d
7ada38f0-1268-11e7-a24b-96d95aa38c32 1e712687-ada3-68f0-93f8-c1ebf8e6fc8c
8cc06fd0-1268-11e7-a24b-96d95aa38c32 1e712688-cc06-6fd0-a828-671acd892c6a
9ea6a6b0-1268-11e7-a24b-96d95aa38c32 1e712689-ea6a-66b0-910c-dbcdb07df7a4
b08d04a0-1268-11e7-a24b-96d95aa38c32 1e71268b-08d0-64a0-bdce-21e3f9808705
c2733b80-1268-11e7-a24b-96d95aa38c32 1e71268c-2733-6b80-adf0-9f593e581a80
d455eff0-1268-11e7-a24b-96d95aa38c32 1e71268d-455e-6ff0-976d-54b9f0c63f24
e63b8a90-1268-11e7-a24b-96d95aa38c32 1e71268e-63b8-6a90-a002-1d1879d81eae
f81e8d20-1268-11e7-a24b-96d95aa38c32 1e71268f-81e8-6d20-b821-f70737f271b4
0a04eb10-1269-11e7-a24b-96d95aa38c32 1e712690-a04e-6b10-ac1f-c595b047b488
1beb21f0-1269-11e7-a24b-96d95aa38c32 1e712691-beb2-61f0-a993-9f20a401adda
2dd158d0-1269-11e7-a24b-96d95aa38c32 1e712692-dd15-68d0-b27d-3284b0309687
3fb7b6c0-1269-11e7-a24b-96d95aa38c32 1e712693-fb7b-66c0-9a9e-961ce88c3c37
519cb520-1269-11e7-a24b-96d95aa38c32 1e712695-19cb-6520-b122-851273f81332
637fb7b0-1269-11e7-a24b-96d95aa38c32 1e712696-37fb-67b0-accd-25b4845fe457
7563a4a0-1269-11e7-a24b-96d95aa38c32 1e712697-563a-64a0-9f9c-7d1b93251fb4
8748ca10-1269-11e7-a24b-96d95aa38c32 1e712698-748c-6a10-9d2a-210067965cb6
992b3060-1269-11e7-a24b-96d95aa38c32 1e712699-92b3-6060-aeed-faaed151443a
ab116740-1269-11e7-a24b-96d95aa38c32 1e71269a-b116-6740-a694-68c004266291

Why not

Performance

By default, this module generates a UUIDv1 as well as a series of random bytes to compose a single UUIDv6. As a result, id generation is slower than some alternatives. Using the disableRandom option improves performance but leaks MAC information.

uuid
  generate UUIDv1 ................................ 1,862,245 op/s
  generate UUIDv4 ................................ 436,730 op/s

uuid-with-v6
  generate UUIDv6 ................................ 280,226 op/s
  generate UUIDv6 without randomness ............. 813,677 op/s

uniqid
  generate UNIQID ................................ 2,619,573 op/s

scuid
  generate SCUID ................................. 920,816 op/s

uild
  generate ULID .................................. 32,165 op/s

The above statistics represent performance on a 2nd-generation Lenovo Carbon X1 (i5 2.90GHz, 8GB DDR3) running Ubuntu 16 LTS (16.04.2). Your mileage may vary. If interested, read more about ulid and scuid, the later of which is a faster version of cuid.

Collision risk

By default, each UUIDv6 ends with 8 hex-encoded random bytes. If your application generates more than 4,294,967,296 ids per 100 nano-second interval you will certainly experience id collision. Furthermore, following the logic of the birthday paradox,the probability of a collision is greater than 50% when generating approximately 78,000 ids per interval:

assert((1 - Math.pow(Math.E, ((-1 * (78000 * (78000 - 1))) / (2 * 4294967296)))) > .5)

Development

Environment

Node.js 4.x (LTS) is required.

Tests

To run the full test suite, including unit tests, collision checks, and linting:

npm test

To run the only the unit test suite:

npm run test-unit

This project maintains 100% coverage of statements, branches, and functions. To determine unit test coverage:

npm run coverage

To run the performance benchmark suite:

npm run benchmark

Contribute

PRs are welcome! PRs must pass unit tests, collision checks, and linting prior to merge. For bugs, please include a failing test which passes when your PR is applied. To enable a git hook that runs npm test prior to pushing, cd into your repo and run:

touch .git/hooks/pre-push
chmod +x .git/hooks/pre-push
echo "npm test" > .git/hooks/pre-push

Versioning

This project follows semantic versioning.

References

• RFC 4122

License

• This module is licensed under the ISC License
• The underlying uuid module is licensed under the MIT License