This project is part of the @thi.ng/umbrella monorepo.

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Configurable K-sortable unique IDs, ULIDs, binary & base-N encoded, 32/48/64bit time resolutions.

Idea based on segmentio/ksuid, though the added flexibility in terms of configuration & implementation also enables the creation of ULIDs:

• ⁽¹⁾ See @thi.ng/base-n for alternatives
• ⁽²⁾ Default: window.crypto, Math.random as fallback

IDs generated w/ this package are composed of a 32, 48 or 64 bit Unix epochs (by default time shifted to free up bits for future timestamps) and N additional bits of a random payload (from a configurable source). IDs can be generated as byte arrays or base-N encoded strings. For the latter, the JS runtime MUST support BigInt.

STABLE - used in production

Search or submit any issues for this package

• @thi.ng/base-n - Arbitrary base-n conversions w/ presets for base16/32/36/58/62/64/85, support for arrays & bigints
• @thi.ng/idgen - Generator of opaque numeric identifiers with optional support for ID versioning and efficient re-use
• @thi.ng/random - Pseudo-random number generators w/ unified API, distributions, weighted choices, ID generation

yarn add @thi.ng/ksuid

ES module import:

<script type="module" src="https://cdn.skypack.dev/@thi.ng/ksuid"></script>

Skypack documentation

For Node.js REPL:

# with flag only for < v16
node --experimental-repl-await

> const ksuid = await import("@thi.ng/ksuid");

Package sizes (gzipped, pre-treeshake): ESM: 827 bytes

• @thi.ng/base-n
• @thi.ng/errors
• @thi.ng/random
• @thi.ng/strings

Generated API docs

import { defKSUID32, defKSUID64, defULID } from "@thi.ng/ksuid";

// init 32bit epoch (resolution: seconds) w/ defaults
const id = defKSUID32();
// init 64bit epoch (resolution: milliseconds), same API
const id = defKSUID64();
// init 48bit epoch (resolution: milliseconds), same API
const id = defULID();

id.next();
// '05XCWbXa3akRqLDBUw4ogCVKGkd'

const a = id.nextBinary()
// Uint8Array(20) [
//     0, 160,  48, 77, 101, 251,
//   244,  17, 155, 97,  24, 101,
//    70,  71, 207, 23,  32,  21,
//   244, 116
// ]

// format a binary KSUID
id.format(a);
// '05XCZ32AaDZfZt0SWE2C22o6cqK'

id.parse("05XCZ32AaDZfZt0SWE2C22o6cqK")
// {
//   epoch: 1610498125000,
//   id: Uint8Array(16) [
//     101, 251, 244,  17, 155, 97,
//      24, 101,  70,  71, 207, 23,
//      32,  21, 244, 116
//   ]
// }

new Date(1610498125000).toISOString()
// '2021-01-13T00:35:25.000Z'

Creating custom IDs:

import { BASE36 } from "@thi.ng/base-n";

// no time shift, 64bit random
const id36 = defKSUID32({ base: BASE36, epoch: 0, bytes: 8 });
// '2VOUKH4K59AG0RXR4XH'

yarn bench

benchmarking: b62, 128bit, n=10000
        warmup... 659.22ms (10 runs)
        executing...
        total: 6402.18ms, runs: 100
        mean: 64.02ms, median: 63.50ms, range: [59.98..96.15]
        q1: 62.64ms, q3: 64.41ms
        sd: 6.93%
benchmarking: b62, 64bit, n=10000
        warmup... 363.35ms (10 runs)
        executing...
        total: 3469.28ms, runs: 100
        mean: 34.69ms, median: 34.41ms, range: [32.61..56.58]
        q1: 33.35ms, q3: 35.41ms
        sd: 7.47%
benchmarking: b62, 32bit, n=10000
        warmup... 218.78ms (10 runs)
        executing...
        total: 2118.93ms, runs: 100
        mean: 21.19ms, median: 20.95ms, range: [20.20..25.74]
        q1: 20.71ms, q3: 21.30ms
        sd: 4.14%

Karsten Schmidt

If this project contributes to an academic publication, please cite it as:

@misc{thing-ksuid,
  title = "@thi.ng/ksuid",
  author = "Karsten Schmidt",
  note = "https://thi.ng/ksuid",
  year = 2020
}

© 2020 - 2021 Karsten Schmidt // Apache Software License 2.0