How to generate a globally unique identifier (GUID, UUID) using Javascript _ javascript skills

This article provides a summary of five methods to implement globally unique identifiers (UUID) using javascript. This method is comprehensive. If you need it, you can refer to the following global unique identifiers (GUID, globally Unique Identifier) is also called UUID (Universally Unique IDentifier ).

GUID is a 128-bit numeric identifier generated by an algorithm. The GUID format is "xxxxxxxx-xxxx-xxxxxxxxxxxx", where x is a 32-bit hexadecimal number in the range of 0-9 or a-f. Ideally, no computer or computer cluster generates two identical guids.

The total number of guids reaches 2 ^ 128 (3.4 × 10 ^ 38), so the probability of randomly generating two identical guids is very small, but not 0. The term GUID sometimes refers to Microsoft's UUID standard implementation.

When generating some nodes, You need to mark them with a unique ID. There are the following high-pass answers for your 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 following comments: the collision rate in this solution is less than 1/2 ^ 122

In addition, we 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('');}

You can specify the length and base number. For example

// 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, we recommend algorithm 1 for individuals. Our friends can make choices based on their own needs.