UUID (UUID) JS generation

The globally unique identifier (guid,globally unique Identifier) is also known as the UUID (universally unique Identifier).

A GUID is a numeric identifier generated by the algorithm with a binary length of 128 bits. The format of the GUID is "Xxxxxxxx-xxxx-xxxx-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 will generate two identical GUIDs.

The total number of GUIDs reaches 2^128 (3.4x10^38), so the probability of randomly generating two identical GUIDs is very small, but not 0. The term GUID also sometimes refers to Microsoft's implementation of the UUID standard.

In the generation of some nodes need to be marked by a unique ID, the following high-ticket answers are available for reference

/* * Generate a random uuid. * * USAGE: Math.uuid(length, radix) * length - the desired number of characters * radix - the number of allowable values for each character. * * EXAMPLES: * // No arguments - returns RFC4122, version 4 ID * >>> Math.uuid() * "92329D39-6F5C-4520-ABFC-AAB64544E172" * * // One argument - returns ID of the specified length * >>> Math.uuid(15) // 15 character ID (default base=62) * "VcydxgltxrVZSTV" * * // Two arguments - returns ID of the specified length, and radix. (Radix must be <= 62) * >>> Math.uuid(8, 2) // 8 character ID (base=2) * "01001010" * >>> Math.uuid(8, 10) // 8 character ID (base=10) * "47473046" * >>> Math.uuid(8, 16) // 8 character ID (base=16) * "098F4D35" */ ( function () { // Private array of chars to use var CHARS =  ‘0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz‘ .split( ‘‘ ); Math.uuid =  function (len, radix) { var chars = CHARS, 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( ‘‘ ); }; // A more performant, but slightly bulkier, RFC4122v4 solution. We boost performance // by minimizing calls to random() Math.uuidFast =  function () { var chars = CHARS, uuid =  new Array(36), rnd=0, r; for ( var i = 0; i < 36; i++) { if (i==8 || i==13 || i==18 || i==23) { uuid[i] =  ‘-‘ ; }  else if (i==14) { uuid[i] =  ‘4‘ ; }  else { if (rnd <= 0x02) rnd = 0x2000000 + (Math.random()*0x1000000)|0; r = rnd & 0xf; rnd = rnd >> 4; uuid[i] = chars[(i == 19) ? (r & 0x3) | 0x8 : r]; } } return uuid.join( ‘‘ ); }; // A more compact, but less performant, RFC4122v4 solution: Math.uuidCompact =  function () { 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); }); }; })();There are several other ways to do it: 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 answer to the following comment cloud: The collision rate under this scheme 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( ‘‘ ); }

This can specify the length and cardinality. Like what

// 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, individual or recommended algorithm one, small partners can choose according to their own needs.

UUID (UUID) JS generation