JavaScript Pseudo-Random ID Generator

Simple Random Id Generator for JavaScript

Sometimes you might need a Random ID generator. The following generator takes an integer from which it will generate a string of that length. Longer string means more permutations and increased uniqueness. The following function was tested with input 15. A sample space of 5,000,000 IDs was generated and all were tested unique.

function generateRandomId(length) {

    "use strict";

    var chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890", returnValue = "", x, i;

    for (x = 0; x < length; x += 1) {

        i = Math.floor(Math.random() * 62);

        returnValue += chars.charAt(i);

    }

    return "ID_" + returnValue;

}

NB: Increase length for increased uniqueness

GenerateRandomId Java Permutation Tester

(Simple test for the function above written in java)

import java.util.*;

public class Main {

   

    public static void main(String[] args) {

       

        int perm = 5000000;

        int counter = 0;

       

        //start time

        System.out.println(new Date().toString());

       

        ArrayList <String> str = new ArrayList<String>();

       

       

        for (int i = 0; i < perm; i++) {

            String temp = generateRandomId(15);

            str.add(temp);

        }

       

        System.out.println("done generating IDs");

       

        System.out.println("Checking for uniqueness ....");

       

        for(Object y : GetUniqueValues(str)){

            counter++;

        }

           

        System.out.println("unique " + counter);

        System.out.println(perm==counter);

       

        System.out.println("done ....");

       

        //end time

        System.out.println(new Date().toString());

               

    }

   

   

    public static String generateRandomId(int length) {

        String chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890", returnValue = "";

        int x, i=0;

        for (x = 0; x < length; x += 1) {

            i = (int) Math.floor(Math.random() * 62);

            returnValue += chars.charAt(i);

        }

        return "JS_" + returnValue;

    }

   

    public static ArrayList<String> GetUniqueValues(Collection<String> values)

    {

        return new ArrayList<String>(new HashSet<String>(values));

    }

}