Random alpha-numeric string in JavaScript? [duplic

Question

This question already has an answer here:

• Generate random string/characters in JavaScript 59 answers

What's the shortest way (within reason) to generate a random alpha-numeric (uppercase, lowercase, and numbers) string in JavaScript to use as a probably-unique identifier?

Answer 1

This is cleaner

Math.random().toString(36).substr(2, length)

Example

Math.random().toString(36).substr(2, 5)

Answer 2

I just came across this as a really nice and elegant solution:

Math.random().toString(36).slice(2)

Answer 3

Or to build upon what Jar Jar suggested, this is what I used on a recent project (to overcome length restrictions):

var randomString = function (len, bits)
{
    bits = bits || 36;
    var outStr = "", newStr;
    while (outStr.length < len)
    {
        newStr = Math.random().toString(bits).slice(2);
        outStr += newStr.slice(0, Math.min(newStr.length, (len - outStr.length)));
    }
    return outStr.toUpperCase();
};

Use:

randomString(12, 16); // 12 hexadecimal characters
randomString(200); // 200 alphanumeric characters

Answer 4

for 32 characters:

for(var c = ''; c.length < 32;) c += Math.random().toString(36).substr(2, 1)

Answer 5

Another variation of answer suggested by JAR.JAR.beans

(Math.random()*1e32).toString(36)

By changing multiplicator 1e32 you can change length of random string.

Answer 6

Nice and simple, and not limited to a certain number of characters:

let len = 20, str = "";
while(str.length < len) str += Math.random().toString(36).substr(2);
str = str.substr(0, len);