


How to generate globally unique identifiers (GUID, UUID) in Javascript_javascript tips
Globally unique identifier (GUID, Globally Unique Identifier) is also called UUID (Universally Unique IDentifier).
GUID is an algorithmically generated numeric identifier with a binary length of 128 bits. The format of the GUID is "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", where x is a 32-digit hexadecimal number in the range of 0-9 or a-f. In an ideal world, no two computers or clusters of computers will generate the same GUID.
The total number of GUIDs reaches 2^128 (3.4×10^38), so the possibility of randomly generating two identical GUIDs is very small, but it is not 0. The term GUID sometimes refers specifically to Microsoft's implementation of the UUID standard.
When generating some nodes, they need to be marked by unique IDs. The following top-voted answers are available 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; };
Comments below the answer: The collision rate under this solution is less than 1/2^^122
In addition, I recommend several algorithms to everyone
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 base. 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, I still recommend Algorithm 1. Friends can choose according to their own needs.

Python is more suitable for data science and automation, while JavaScript is more suitable for front-end and full-stack development. 1. Python performs well in data science and machine learning, using libraries such as NumPy and Pandas for data processing and modeling. 2. Python is concise and efficient in automation and scripting. 3. JavaScript is indispensable in front-end development and is used to build dynamic web pages and single-page applications. 4. JavaScript plays a role in back-end development through Node.js and supports full-stack development.

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JavaScript's application in the real world includes front-end and back-end development. 1) Display front-end applications by building a TODO list application, involving DOM operations and event processing. 2) Build RESTfulAPI through Node.js and Express to demonstrate back-end applications.

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Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

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