| 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495 | import rng from './rng.js';import { unsafeStringify } from './stringify.js'; // **`v1()` - Generate time-based UUID**//// Inspired by https://github.com/LiosK/UUID.js// and http://docs.python.org/library/uuid.htmllet _nodeId;let _clockseq; // Previous uuid creation timelet _lastMSecs = 0;let _lastNSecs = 0; // See https://github.com/uuidjs/uuid for API detailsfunction v1(options, buf, offset) {  let i = buf && offset || 0;  const b = buf || new Array(16);  options = options || {};  let node = options.node || _nodeId;  let clockseq = options.clockseq !== undefined ? options.clockseq : _clockseq; // node and clockseq need to be initialized to random values if they're not  // specified.  We do this lazily to minimize issues related to insufficient  // system entropy.  See #189  if (node == null || clockseq == null) {    const seedBytes = options.random || (options.rng || rng)();    if (node == null) {      // Per 4.5, create and 48-bit node id, (47 random bits + multicast bit = 1)      node = _nodeId = [seedBytes[0] | 0x01, seedBytes[1], seedBytes[2], seedBytes[3], seedBytes[4], seedBytes[5]];    }    if (clockseq == null) {      // Per 4.2.2, randomize (14 bit) clockseq      clockseq = _clockseq = (seedBytes[6] << 8 | seedBytes[7]) & 0x3fff;    }  } // UUID timestamps are 100 nano-second units since the Gregorian epoch,  // (1582-10-15 00:00).  JSNumbers aren't precise enough for this, so  // time is handled internally as 'msecs' (integer milliseconds) and 'nsecs'  // (100-nanoseconds offset from msecs) since unix epoch, 1970-01-01 00:00.  let msecs = options.msecs !== undefined ? options.msecs : Date.now(); // Per 4.2.1.2, use count of uuid's generated during the current clock  // cycle to simulate higher resolution clock  let nsecs = options.nsecs !== undefined ? options.nsecs : _lastNSecs + 1; // Time since last uuid creation (in msecs)  const dt = msecs - _lastMSecs + (nsecs - _lastNSecs) / 10000; // Per 4.2.1.2, Bump clockseq on clock regression  if (dt < 0 && options.clockseq === undefined) {    clockseq = clockseq + 1 & 0x3fff;  } // Reset nsecs if clock regresses (new clockseq) or we've moved onto a new  // time interval  if ((dt < 0 || msecs > _lastMSecs) && options.nsecs === undefined) {    nsecs = 0;  } // Per 4.2.1.2 Throw error if too many uuids are requested  if (nsecs >= 10000) {    throw new Error("uuid.v1(): Can't create more than 10M uuids/sec");  }  _lastMSecs = msecs;  _lastNSecs = nsecs;  _clockseq = clockseq; // Per 4.1.4 - Convert from unix epoch to Gregorian epoch  msecs += 12219292800000; // `time_low`  const tl = ((msecs & 0xfffffff) * 10000 + nsecs) % 0x100000000;  b[i++] = tl >>> 24 & 0xff;  b[i++] = tl >>> 16 & 0xff;  b[i++] = tl >>> 8 & 0xff;  b[i++] = tl & 0xff; // `time_mid`  const tmh = msecs / 0x100000000 * 10000 & 0xfffffff;  b[i++] = tmh >>> 8 & 0xff;  b[i++] = tmh & 0xff; // `time_high_and_version`  b[i++] = tmh >>> 24 & 0xf | 0x10; // include version  b[i++] = tmh >>> 16 & 0xff; // `clock_seq_hi_and_reserved` (Per 4.2.2 - include variant)  b[i++] = clockseq >>> 8 | 0x80; // `clock_seq_low`  b[i++] = clockseq & 0xff; // `node`  for (let n = 0; n < 6; ++n) {    b[i + n] = node[n];  }  return buf || unsafeStringify(b);}export default v1;
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