Generate a random string of ASCII characters

randomAsciiGenerator.js

const generateRandomAsciiString = (len, cap=false, lower=false, num=false, special=false) => {
  let str = '';
  const includesCap = str => !![...Array(26)]
    .map((n, i) => String.fromCharCode(i + 65))
    .filter(c => str.includes(c)).length;
  const includesLower = str => !![...Array(26)]
    .map((n, i) => String.fromCharCode(i + 97))
    .filter(c => str.includes(c)).length;
  const includesNum = str => !![...Array(10)]
    .map((n, i) => String.fromCharCode(i + 48))
    .filter(c => str.includes(c)).length;
  const includesSpecial = str => !![
    ...[...Array(15)].map((n, i) => String.fromCharCode(i + 33)),
    ...[...Array(7)].map((n, i) => String.fromCharCode(i + 58)),
    ...[...Array(4)].map((n, i) => String.fromCharCode(i + 123)),
  ].filter(c => str.includes(c)).length;
  while (
    !str.length ||
    !((includesCap(str) || !cap)
    && (includesLower(str) || !lower)
    && (includesNum(str) || !num)
    && (includesSpecial(str) || !special))
  ) {
    str = [...Array(90)]
      .map((n, i) => String.fromCharCode(i + 37))
      .sort(() => 0.5 - Math.random())
      .slice(0,len)
      .join('');
  }
  return str;
};

generates an ASCII string of random length.

inputs

name	type	description
len	integer	length of output string, in number of characters
cap	boolean	whether or not the output string must contain capital letters
lower	boolean	whether or not the output string must contain lower case letters
num	boolean	whether or not the output string must contain numerals
special	boolean	whether or not the output string must contain special characters

example usage

generateRandomAsciiString(10, true, false, true, false);
=> "$0<l#CYv]s"

[...Array(10)].forEach(() => console.log(generateRandomAsciiString(10, true, false, true, false)));
=>
`)(:6<3FKLA`
`V!"/3D6B%E`
`<1jM\h;ABy`
`@3mPVLJ+_q`
`No/0IH4Q>u`
`^o]N)P#7"q`
`Z'(@"%LNr0`
`m#[ReG.6FI`
`s@"MG')4H/`
`!p#S5UKndF`