@thi.ng/ksuid/aksuid.js

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

import { BASE62 } from "@thi.ng/base-n/62";
import { assert } from "@thi.ng/errors/assert";
import { randomBytes, randomBytesFrom } from "@thi.ng/random/random-bytes";
import { padLeft } from "@thi.ng/strings/pad-left";
class AKSUID {
  constructor(epochSize, opts) {
    this.epochSize = epochSize;
    this.base = opts.base || BASE62;
    this.rnd = opts.rnd;
    this.epoch = opts.epoch;
    this.size = this.epochSize + opts.bytes;
    this.encodedSize = this.base.size(2 ** (this.size * 8) - 1);
    this.pad = padLeft(this.encodedSize, this.base.base[0]);
    this.tmp = new Uint8Array(this.size);
  }
  size;
  encodedSize;
  base;
  epoch;
  tmp;
  rnd;
  pad;
  next() {
    return this.format(this.nextBinary(this.tmp));
  }
  nextBinary(buf) {
    return this.fromEpochBinary(void 0, buf);
  }
  timeOnly(epoch) {
    return this.format(
      this.timeOnlyBinary(epoch, this.tmp.fill(0, this.epochSize))
    );
  }
  fromEpoch(epoch) {
    return this.format(this.fromEpochBinary(epoch, this.tmp));
  }
  fromEpochBinary(epoch, buf) {
    buf = this.timeOnlyBinary(epoch, buf);
    return this.rnd ? randomBytesFrom(this.rnd, buf, this.epochSize) : randomBytes(buf, this.epochSize);
  }
  format(buf) {
    this.ensureSize(buf);
    return this.pad(this.base.encodeBytes(buf));
  }
  ensureSize(buf) {
    assert(
      buf.length == this.size,
      `illegal KSUID size, expected ${this.size} bytes`
    );
    return buf;
  }
  ensureTime(t, max) {
    assert(t >= 0, "configured base epoch must be in the past");
    max && assert(t <= max, `given epoch is out of range ([0...${max}])`);
    return t;
  }
  u32(buf, i = 0) {
    return (buf[i] << 24 | buf[i + 1] << 16 | buf[i + 2] << 8 | buf[i + 3]) >>> 0;
  }
}
export {
  AKSUID
};