uuidv7

An experimental implementation of the proposed UUIDv7

import { uuidv7 } from "uuidv7";

const result = uuidv7(); // e.g. "0619786f-54be-78f3-9a02-b3376dac11d7"

See draft-peabody-dispatch-new-uuid-format-02.

Field and bit layout

This implementation produces identifiers with the following bit layout:

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                            unixts                             |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|unixts |        subsec         |  ver  |        subsec         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|var|                         rand                              |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                             rand                              |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Where:

• The 36-bit unixts field is dedicated to the Unix timestamp in seconds.
• Two 12-bit subsec fields are filled with the 24-bit sub-second fraction, which is derived from the millisecond precision timestamp and randomly chosen pseudo-sub-millisecond fraction. The pseudo-sub-millisecond fraction is incremented by a certain unit for a new UUID generated within the same millisecond and is reset to a new random number whenever the millisecond timestamp changes.
• The 4-bit ver field is set at 0111.
• The 2-bit var field is set at 10.
• The remaining 62 rand bits are filled with a cryptographically strong random number.