Javascript method for generating globally unique identifiers (GUID UUID)

The global one-only identifier (GUID, Globally Unique Identifier) is also known as UUID(Universally Unique IDentifier).

ES11en is a 128 bit binary numeric identifier generated by an algorithm. The format of GUID is "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", where x is a 32-bit 106-base number in the range 0-9 or a-f. Ideally, no machine and no cluster of machines will ever generate two identical GUID.

The total number of GUID is 2^128 (3.4×10^38), so the probability of randomly generating two identical GUID is very small, but not zero. The term GUID1 is also sometimes used specifically to refer to Microsoft's implementation of the UUID standard.

When generating a number of nodes, it needs to be marked by only 1ID. There are the following answers for reference

function generateUUID() {
var d = new Date().getTime();
var uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
  var r = (d + Math.random()*16)%16 | 0;
  d = Math.floor(d/16);
  return (c=='x' ? r : (r&0x3|0x8)).toString(16);
});
return uuid;
};

The collision rate under this scheme is less than 1/2^ 122

In addition, I recommend several algorithms

Algorithm 2

function guid() {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
    var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
    return v.toString(16);
  });
}
 

Algorithm 3

function guid() {
  function S4() {
    return (((1+Math.random())*0x10000)|0).toString(16).substring(1);
  }
  return (S4()+S4()+"-"+S4()+"-"+S4()+"-"+S4()+"-"+S4()+S4()+S4());
}
 

Algorithm 4

function uuid(len, radix) {
  var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('');
  var uuid = [], i;
  radix = radix || chars.length;
 
  if (len) {
   // Compact form
   for (i = 0; i < len; i++) uuid[i] = chars[0 | Math.random()*radix];
  } else {
   // rfc4122, version 4 form
   var r;
 
   // rfc4122 requires these characters
   uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-';
   uuid[14] = '4';
 
   // Fill in random data. At i==19 set the high bits of clock sequence as
   // per rfc4122, sec. 4.1.5
   for (i = 0; i < 36; i++) {
    if (!uuid[i]) {
     r = 0 | Math.random()*16;
     uuid[i] = chars[(i == 19) ? (r & 0x3) | 0x8 : r];
    }
   }
  }
 
  return uuid.join('');
}

This can specify the length and cardinality. Such as

// 8 character ID (base=2)
uuid(8, 2) // "01001010"
// 8 character ID (base=10)
uuid(8, 10) // "47473046"
// 8 character ID (base=16)
uuid(8, 16) // "098F4D35"

Algorithm 5

function uuid() {
  var s = [];
  var hexDigits = "0123456789abcdef";
  for (var i = 0; i < 36; i++) {
    s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);
  }
  s[14] = "4"; // bits 12-15 of the time_hi_and_version field to 0010
  s[19] = hexDigits.substr((s[19] & 0x3) | 0x8, 1); // bits 6-7 of the clock_seq_hi_and_reserved to 01
  s[8] = s[13] = s[18] = s[23] = "-";
 
  var uuid = s.join("");
  return uuid;
}
 

Of course, the individual or recommended algorithm 1, friends can according to their own needs to choose.