Generate string/characters in JavaScript

Question

Now, I want to set the output generated in constant( first two in letters,last three in numeric). What code should I use? Thanks.

Javascript

function makeid() {
  var text = "";
  var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

  for (var i = 0; i < 5; i++)
    text += possible.charAt(Math.floor(Math.random() * possible.length));

  return text;
}
console.log(makeid());

score 3 · Accepted Answer · answered Aug 23 '17 at 00:31

3

You could try separating your 'possible' string into possibleNums and possibleChars

var possibleNums = "0123456789";
var possibleAlpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"

for (var i = 0; i < 2; i++) {
    text += possibleAlpha.charAt(Math.floor(Math.random() * possibleAlpha.length));
}

for (var i = 0; i < 3; i++) {
    text += possibleNums.charAt(Math.floor(Math.random() * possibleNums.length));
}

answered Aug 23 '17 at 00:31

Michael Horn

3,819
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22

was just about to post the same solution – TheRealMrCrowley Aug 23 '17 at 00:32

score 1 · Answer 2 · answered Aug 23 '17 at 00:32

Try this:

function makeid() {
  var text = "";
  var possibleLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  var possibleNumbers = "0123456789";

  for (var i = 0; i < 2; i++)
    text += possibleLetters.charAt(Math.floor(Math.random() * possibleLetters.length));
  for (var i = 0; i < 3; i++)
    text += possibleNumbers.charAt(Math.floor(Math.random() * possibleNumbers.length));

  return text;
}

solimanware · Answer 3 · 2017-08-23T00:51:20.647

Here you are -code in ES6-:

You need to separate numbers and characters,

But to generate random unique id you can refer to here

const makeid = () => {
  let id = '';
  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
  const nums = '0123456789'
  for (let i = 0; i < 2; i++) {
    id += chars[Math.floor(Math.random() * chars.length) + 1]
  }
  for (let i = 0; i < 3; i++) {
    id += nums[Math.floor(Math.random() * nums.length) + 1]
  }
  return id
}

And here's more functional and readable code:

const makeid = () => {
  let id = '';
  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
  const nums = '0123456789'
  id += generate(2, chars)
  id += generate(3, nums)
  return id
}
const generate = (number, string) => {
  let res = ''
  for (let i = 0; i < number; i++) {
    res += string[Math.floor(Math.random() * string.length) + 1]
  }
  return res
}
console.log(makeid())

score 0 · Answer 4 · answered Aug 23 '17 at 01:08

Actually you don't need the string "possible" you can use ascii values.

below is the code.

function makeid() {
  var text = "";
var x,y;
  for (var i = 0; i < 2; i++){
  x=(Math.floor(Math.random()*2))?( Math.floor(Math.random() * (26)) + 65):( Math.floor(Math.random() * (26)) + 97)
  text+=String.fromCharCode(x)
  }
  for (var i = 0; i < 3; i++){
 x=String.fromCharCode(Math.floor(Math.random() * (10)) + 48)
  text+=x
  } 
  return text;
}
console.log(makeid());

joopmicroop · Answer 5 · 2017-08-23T01:32:54.197

var randomBetween = (min,max)=> Math.floor(max-Math.random()*(max-min));
var randomLetter = ()=> String.fromCharCode(randomBetween(65,90)+(Math.round(Math.random())?32:0));
var makeId = pattern=> (pattern||'xx000').replace(/./g, v=>isNaN(v)?randomLetter():randomBetween(0,9));

console.log(makeId());

Or you can also make your own patterns for example:

makeId('aaaaaa11111');   //returns: lUmKUe07356
makeId('a1a1a1a1a1a1a'); //returns: b2N5U8J2m7r2C

Any matching letter will be replaced with a random one, any number with a random number.

score 0 · Answer 6 · answered Aug 23 '17 at 02:53

You can try the following:

function getRandomId() {
    return String.fromCharCode((Math.random() < 0.5 ? 65 : 97) + Math.floor(Math.random() * 26)) +
        String.fromCharCode((Math.random() < 0.5 ? 65 : 97) + Math.floor(Math.random() * 26)) +
        Math.random().toString(10).substring(2, 5);
}

for (var i = 0; i < 5; i++) {
    console.log(getRandomId());
}

/* Sample Output:
wc257
bR495
Li690
cF973
kf790
*/

Generate string/characters in JavaScript

6 Answers6