javascript - generate 18 digit unique number - Stack Overflow

I want to create a function in my NodeJS application which generates unique 18 digit numbers. What I'm expecting is to get unique 18 digit numbers like below:

73306495056092753667  

I thought of using the below logic, by bining Date.now() with Math.random():

Date.now()+""+Math.floor(Math.random()*10000000)  

But in cases where my function is called exactly at the same millisecond, and if in the same cases, Math.random() returns the same value, the above logic wont return unique ID's.

In NodeJS/Javascript, is there any module like UUID which generates globally unique numerical values? Or can anyone help me create an algorithm that will generate unique ID's?

I want to create a function in my NodeJS application which generates unique 18 digit numbers. What I'm expecting is to get unique 18 digit numbers like below:

73306495056092753667  

I thought of using the below logic, by bining Date.now() with Math.random():

Date.now()+""+Math.floor(Math.random()*10000000)  

But in cases where my function is called exactly at the same millisecond, and if in the same cases, Math.random() returns the same value, the above logic wont return unique ID's.

In NodeJS/Javascript, is there any module like UUID which generates globally unique numerical values? Or can anyone help me create an algorithm that will generate unique ID's?

• javascript

Share Improve this question Follow edited May 7, 2020 at 5:38 codeandcloud 55.4k4747 gold badges168168 silver badges259259 bronze badges asked May 7, 2020 at 5:02 Tony MathewTony Mathew 91011 gold badge1313 silver badges4444 bronze badges 4

• You might want to look into how Mongo generates its ids (as an example). – ProgrammingLlama Commented May 7, 2020 at 5:03
• @John I checked that, Mongo generates alpha-numerical ids. What I want it strictly numerical – Tony Mathew Commented May 7, 2020 at 5:49
• I said how it generates its ids. I didn't say you should generate the same ids as Mongo. And it's alphanumeric because Mongo represents the number as hexadecimal. Anyway, it generates a 4-byte timestamp, a 5-byte random value, and a 3-byte incrementing counter. That way even if you generate 2 numbers at the exact same moment, you get two different ids. – ProgrammingLlama Commented May 7, 2020 at 8:18
• Please note that hexadecimal is just a representation of binary data, and as such you could also interpret that same binary data as numbers, for example. The Mongo ID 507f1f77bcf86cd799439011 could also be written as 24912482966938930280208240657 in decimal. – ProgrammingLlama Commented May 7, 2020 at 8:21

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3 Answers 3

Sorted by: Reset to default 12

Here is a solution using nanoid (npm install -S nanoid):

const { customAlphabet } = require('nanoid')
const nanoid = customAlphabet('1234567890', 18)
console.log(nanoid()) // sample outputs => 455712511712968405, 753952709650782495

Try appending a random number between 10000 and 99999 to new Date().valueOf()

const numbers = [...Array(90000).keys()].map(n => n + 10000);
let filteredNumbers = numbers;
let timeStamp = new Date().valueOf();
let rand = 0;
const generateRandomNumber = _ => {
  const currentTimeStamp = new Date().valueOf();
  if (timeStamp === currentTimeStamp && rand !== 0) {
    filteredNumbers = filteredNumbers.filter(n => n !== value)
  } else {
    timeStamp = currentTimeStamp;
    filteredNumbers = numbers;
  }
  rand = filteredNumbers[Math.floor(Math.random() * filteredNumbers.length)];
  return parseInt(new Date().valueOf() + "" + rand, 10);
};

document.querySelector('#generate')
  .addEventListener('click', _ => {
    const uuid = generateRandomNumber();
    console.log(uuid);
  });

<button id="generate">Generate UUID</button>

Exactly Same 18 Digits as my laravel Projects

Well In this case I Created that with 10 digiths Seconds + randomiser like 3+3+2 digits Maybe It Kind of what @Naveen did