Generate a random string in JavaScript In a short and fast way!

Random-string

 //http://stackoverflow.com/questions/105034/how-to-create-a-guid-uuid-in-javascript
 Math.random().toString(36).substring(2, 15) + Math.random().toString(36).substring(2, 15);

Silly oneliners:

[a-zA-Z0-9]:

for(var a = ''; a.length < 40;) a += "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz"[(Math.random() * 60) | 0]

[0-z]

String.fromCharCode.apply(0, Array(40).fill(0).map(() => Math.random() * 74 + 42) | 0)

[0-9a-z]

for(var a = '', b = 36; a.length < 40;) a += (Math.random() * b | 0).toString(b)

[0-9A-Z]

for(var a = ''; r = Math.random() * 42, a.length < 40;) a += r < 10 || r > 16 ? String.fromCharCode(48 + r | 0) : ''

Using crypto: crypto.randomBytes(32).toString('base64'), adjust the parameter to randomBytes for the length you need.

Perfect, thank you!

nice

[...Array(10)].map(i=>(~~(Math.random()*36)).toString(36)).join('')

this is a little better, you can specify any length 💪

where is the i being used? better off providing an empty function like this?

const randomString = (length) => [ ...Array(length) ].map(() => (~~(Math.random() * 36)).toString(36)).join('');

console.log(randomString(14));

that's good, thanks😊

So simple, so useful.

thank you so much 👍

Thank you

Array.from({length:10}, () => String.fromCharCode(String(parseInt(65 + Math.random() * (122 - 65))).replace(/9[1-6]/,'90'))).join('')

Is there any simple way to generate string without numbers in it?

Is there any simple way to generate string without numbers in it?

const randcharset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

const randchars = (function (R,M) {
    var L = R.length,r=M.random, f= M.floor;
    return function (len) {
        var i,s="";
        for (i=0;i<len;i++) s += R[f(r() * L)];
        return s;
    };
})(randcharset.split(''),Math);

for example

document.write("hello:"+randchars(4));

"doadiahdoiawd"

Of course you would have to type sporadically every time but I believe this is the fastest performing solution.

// only printable
Array(8).fill().map(_ => String.fromCharCode(33 + Math.random() * (127 - 33))).join('')

Noice. 👌 Thanks!!

Awesome!!!

Pretty cool!

Brilliant!

This is my version. Generate random string with numbers, lower and upper case.

const randomString=length=>Math.random().toString(36).substr(2,length).split("").map(e=>Math.random()<Math.random()?e.toUpperCase():e).join().replaceAll(",","");

console.log(randomString(10)); //8itPVoPBdU

Using recursion with the option of providing a prefix.

function randomStr(minLength = 0, acc = '') {
    if (acc.length <= minLength) {
        const str = Math.random().toString(36).slice(2);
        return randomStr(minLength, acc.concat(str))
    }

    return acc.slice(0, minLength);
}

randomStr(10) // => 'fvaj2hm2na'
randomStr(30, 'https://short.codes/') // => 'https://short.codes/jtmx66qr06'

  const idString = async (string_length) => {
    var random_str = "";
    var characters =
      "ABCDEFGHIJKLMNOPQRSTUVWXYZqeytrpolkadjsghfgmnbzxcvnQPOWEYRKASJHDGFMNBCVX--___-_jsfhrlg-_124903564576986483658fgh4sdfh687e4h897WETHJ68F7G4688471877GFHJFFGJ87469857468746hfghwrtiyj4598yhdjkhgnk";
    for (let index = 0; index < string_length; index++) {
      random_str += characters.charAt(
        Math.floor(Math.random() * characters.length)
      );
    }
    let string = `${random_str}`;
    console.log(string);
    return string;
  };

@zeelkakdiya constructive feedback to improve this code:

1. This is not an async function, it does not use promises
2. var is used rather than let and in some cases const are more appropriate
3. let string does not need ${}
4. console.log is not useful in production code and actually slows down this function
5. let string to return could be removed.
6. casing is inconsistent

const generateID = (stringLength = 20) => {
    let randomStr = "";
    const characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZqeytrpolkadjsghfgmnbzxcvnQPOWEYRKASJHDGFMNBCVX--___-_jsfhrlg-_124903564576986483658fgh4sdfh687e4h897WETHJ68F7G4688471877GFHJFFGJ87469857468746hfghwrtiyj4598yhdjkhgnk";
    for (let index = 0; index < stringLength; index++) {
      randomStr += characters.charAt(
        Math.floor(Math.random() * characters.length)
      );
    }
    return randomStr;
  };