A JavaScript implementation of UUID version 7
npm install uuidv7
``javascript
import { uuidv7 } from "uuidv7";
const result = uuidv7(); // e.g., "017fe537-bb13-7c35-b52a-cb5490cce7be"
`
On browsers and Deno:
`javascript
import { uuidv7 } from "https://unpkg.com/uuidv7@^1";
const result = uuidv7(); // e.g., "017fe537-bb13-7c35-b52a-cb5490cce7be"
`
Command-line interface:
`bash`
$ npx uuidv7
0189f7e5-c883-7106-8272-ccb7fcba0575
$
$ npx uuidv7 -n 4
0189f7ea-ae2c-7809-8aeb-b819cf5e9e7f
0189f7ea-ae2f-72b9-9be8-9c3c5a60214f
0189f7ea-ae2f-72b9-9be8-9c3d224082ef
0189f7ea-ae2f-72b9-9be8-9c3e3e8abae8
See RFC 9562.
This implementation produces identifiers with the following bit layout:
`text`
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| unix_ts_ms |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| unix_ts_ms | ver | counter |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|var| counter |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rand |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where:
- The 48-bit unix_ts_ms field is dedicated to the Unix timestamp inver
milliseconds.
- The 4-bit field is set at 0111.counter
- The 42-bit field accommodates a counter that ensures the increasingunix_ts_ms
order of IDs generated within a millisecond. The counter is incremented by one
for each new ID and is reset to a random number when the changes.var
- The 2-bit field is set at 10.rand
- The remaining 32 bits are filled with a cryptographically strong random
number.
The 42-bit counter is sufficiently large, so you do not usually need to worryunix_ts_ms
about overflow, but in an extremely rare circumstance where it overflows, this
library increments the field to continue instant monotonicunix_ts_ms
generation. As a result, the may have a greater value than that of
the system's real-time clock. (See also [Why so large counter? (42bits)]).
UUIDv7, by design, relies on the system clock to guarantee the monotonically
increasing order of generated IDs. A generator may not be able to produce a
monotonic sequence if the system clock goes backwards. This library ignores a
clock rollback and reuses the previous unix_ts_ms unless the clock rollback is
considered significant (by default, more than ten seconds). If such a
significant rollback takes place, this library resets the generator by default
and thus breaks the increasing order of generated IDs.
[Why so large counter? (42bits)]: https://github.com/LiosK/uuidv7/issues/13#issuecomment-2306922356
This library also supports the generation of UUID version 4:
`javascript
import { uuidv4 } from "uuidv7";
const result = uuidv4(); // e.g., "83229083-75c3-4da5-8378-f88ef1a2bcd1"
`
uuidv7obj() and uuidv4obj() return an object that represents a UUID as a
16-byte byte array:
`javascript
import { uuidv7obj } from "uuidv7";
const object = uuidv7obj();
console.log(object.bytes); // Uint8Array(16) [ ... ]
console.log(String(object)); // e.g., "017fea6b-b877-7aef-b422-57db9ed15e9d"
console.assert(object.getVariant() === "VAR_10");
console.assert(object.getVersion() === 7);
console.assert(object.clone().equals(object));
console.assert(object.compareTo(uuidv7obj()) < 0);
`
The V7Generator primitive allows to utilize a separate counter state from that
of the global generator. It also provides a fallible variant of the generator
function to give an absolute guarantee of the increasing order of UUIDs despite
a significant rollback of the system timestamp source.
`javascript
import { V7Generator } from "uuidv7";
const g = new V7Generator();
const x = g.generate();
const y = g.generateOrAbort();
if (y === undefined) {
throw new Error("The clock went backwards by ten seconds!");
}
console.assert(x.compareTo(y) < 0);
`
See the API documentation for details.
The CommonJS entry point is deprecated and provided for backward compatibility
purposes only. The entry point is no longer tested and will be removed in the
future.
Licensed under the Apache License, Version 2.0.
Uuid25 provides the conversion to/from a
condensed, sortable, case-insensitive, 25-digit Base36 representation of UUID as
well as other well-known textual representations. Uuid25 is available in several
languages including Go, JavaScript, Python, Rust, and Swift.
`javascript
import { uuidv7obj } from "uuidv7";
import { Uuid25 } from "uuid25";
const uuid25 = Uuid25.fromBytes(uuidv7obj().bytes);
console.log(uuid25.value);
// e.g., "03a2s63x4x0b9mev9e88i7gpm"
console.log(uuid25.toHex());
// e.g., "0189f8068f1a79b6bb21123c6accc25a"
console.log(uuid25.toHyphenated());
// e.g., "0189f806-8f1a-79b6-bb21-123c6accc25a"
console.log(uuid25.toBraced());
// e.g., "{0189f806-8f1a-79b6-bb21-123c6accc25a}"
console.log(uuid25.toUrn());
// e.g., "urn:uuid:0189f806-8f1a-79b6-bb21-123c6accc25a"
``