How to generate unique ID with node js

Question

function generate count        var founded   false           sym    abcdefghijklmnopqrstuvwxyz1234567890           str           while  founded            for var i   0  i  lt  count  i                  str     sym parseInt Math random       sym length                       base getID string  function err  res                if  res length                    founded   true     How to do it                                      return str      How to set a variable value with database query callback  How I can do it

User · Answer

The solutions here are old and now deprecated: https://github.com/uuidjs/uuid#deep-requires-now-deprecated

Use this:

npm install uuid

//add these lines to your code
const { v4: uuidv4 } = require('uuid');
var your_uuid = uuidv4();
console.log(your_uuid);

User · Answer

Install NPM uuid package  sources  https   github com kelektiv node-uuid    npm install uuid   and use it in your code   var uuid   require  uuid      Then create some ids         Generate a v1  time-based  id uuid v1       - gt   6c84fb90-12c4-11e1-840d-7b25c5ee775a      Generate a v4  random  id uuid v4       - gt   110ec58a-a0f2-4ac4-8393-c866d813b8d1         UPDATE 3 1 0 The above usage is deprecated  so use this package like this     const uuidv1   require  uuid v1    uuidv1       - gt   6c84fb90-12c4-11e1-840d-7b25c5ee775a    const uuidv4   require  uuid v4    uuidv4       - gt   110ec58a-a0f2-4ac4-8393-c866d813b8d1          UPDATE 7 x And now the above usage is deprecated as well  so use this package like this     const   v1  uuidv1     require  uuid    uuidv1       - gt   6c84fb90-12c4-11e1-840d-7b25c5ee775a    const   v4  uuidv4     require  uuid    uuidv4       - gt   6c84fb90-12c4-11e1-840d-7b25c5ee775a

User · Answer

Extending from YaroslavGaponov s answer  the simplest implementation is just using Math random    Math random    Mathematically  the chances of fractions being the same in a real space  0  1  is theoretically 0  Probability-wise it is approximately close to 0 for a default length of 16 decimals in node js  And this implementation should also reduce arithmetic overflows as no operations are performed  Also  it is more memory efficient compared to a string as Decimals occupy less memory than strings  I call this the  quot Fractional-Unique-ID quot   Wrote code to generate 1 000 000 Math random   numbers and could not find any duplicates  at least for default decimal points of 16   See code below  please provide feedback if any   random numbers       for  i   0  i  lt  1000000  i          random numbers push Math random           random numbers push Math random   toFixed 13     depends decimals default 16      if  i     1000000        console log  quot Before checking duplicate quot        console log random numbers length       console log  quot After checking duplicate quot        random set   new Set random numbers      Set removes duplicates    console log     random set  length      length is still the same after removing

User · Answer

used https   www npmjs com package uniqid in npm   npm i uniqid   It will always create unique id s based on the current time  process and machine name    With the current time the ID s are always unique in a single process  With the Process ID the ID s are unique even if called at the same time from multiple processes  With the MAC Address the ID s are unique even if called at the same time from multiple machines and processes    Features -   Very fast Generates unique id s on multiple processes and machines even if called at the same time  Shorter 8 and 12 byte versions with less uniqueness

User · Answer

If some one needs cryptographic-strong UUID  there is solution for that as well   https   www npmjs com package generate-safe-id  npm install generate-safe-id      Why not UUIDs       Random UUIDs  UUIDv4  do not have enough entropy to be universally   unique  ironic  eh    Random UUIDs have only 122 bits of entropy    which suggests that a duplicate will occur after only 2 61 IDs    Additionally  some UUIDv4 implementations do not use a   cryptographically strong random number generator       This library generates 240-bit IDs using the Node js crypto RNG    suggesting the first duplicate will occur after generating 2 120 IDs    Based on the current energy production of the human race  this   threshold will be impossible to cross for the foreseeable future    var generateSafeId   require  generate-safe-id     var id   generateSafeId       id     zVPkWyvgRW-7pSk0iRzEhdnPcnWfMRi-ZcaPxrHA

User · Answer

More easy and without addition modules  Math random   toString 26  slice 2

User · Answer

to install uuid npm install --save uuid  uuid is updated and the old import const uuid  require  uuid v4     is not working and we should now use this import const  v4 uuid    require  uuid     and for using it use as a funciton like this const  createdPlace         id  uuid        title      description      location coordinates      address      creator

User · Answer

I am using the following and it is working fine plus without any third-party dependencies   const     randomBytes     require  crypto     const uid   Math random   toString 36  slice 2    randomBytes 8  toString  hex     new Date   getTime

User · Answer

The fastest possible way to create random 32-char string in Node is by using native crypto module   const crypto   require  crypto     const id   crypto randomBytes 16  toString  hex     console log id        gt  f9b327e70bbcf42494ccb28b2d98e00e

User · Answer

edit  shortid has been deprecated  The maintainers recommend to use nanoid instead   Another approach is using the shortid package from npm  It is very easy to use  var shortid   require  shortid    console log shortid generate        e g  S1cudXAF  and has some compelling features   ShortId creates amazingly short non-sequential url-friendly unique ids  Perfect for url shorteners  MongoDB and Redis ids  and any other id users might see   By default 7-14 url-friendly characters  A-Z  a-z  0-9   - Non-sequential so they are not predictable  Can generate any number of ids without duplicates  even millions per day  Apps can be restarted any number of times without any chance of repeating an id

User · Answer

Simple  time based  without dependencies    new Date    getTime   toString 36    Output  jzlatihl    plus random number  Thanks to  Yaroslav Gaponov s answer    new Date    getTime   toString 36    Math random   toString 36  slice 2    Output jzlavejjperpituute

User · Answer

nanoid achieves exactly the same thing that you want  Example usage  const   nanoid     require  quot nanoid quot    console log nanoid        gt   quot n340M4XJjATNzrEl5Qvsh quot

User · Answer

node-uuid is deprecated so please use uuid  npm install uuid --save    Generate a v1 UUID  time-based   const uuidV1   require  uuid v1    uuidV1       - gt   6c84fb90-12c4-11e1-840d-7b25c5ee775a       Generate a v4 UUID  random   const uuidV4   require  uuid v4    uuidV4       - gt   110ec58a-a0f2-4ac4-8393-c866d813b8d1     Npm link

User · Answer

It s been some time since I used node js  but I think I might be able to help   Firstly  in node  you only have a single thread and are supposed to use callbacks  What will happen with your code  is that base getID query will get queued up by for execution  but the while loop will continusouly run as a busy loop pointlessly   You should be able to solve your issue with a callback as follows   function generate count  k        var  sym    abcdefghijklmnopqrstuvwxyz1234567890       var str            for var i   0  i  lt  count  i              str     sym parseInt Math random       sym length               base getID str  function err  res            if  res length              k str                       use the continuation           else generate count  k      otherwise  recurse on generate             And use it as such  generate 10  function uniqueId        have a uniqueId      I haven t coded any node js in around 2 years and haven t tested this  but the basic idea should hold      don t use a busy loop  and use callbacks  You might want to have a look at the node async package

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