function allUnique(str) {
  const chars = str.split("").reduce((acc, next, i, arr) => {
    return acc.includes(next) ? arr.splice(1) : (acc = acc + next);
  }, "");
  return str.length === chars.length;
}


allUnique("abcdefghijklmnopqrstuvwxyz 1234567890");
allUnique("Jan Honza Pozivil");
allUnique("`1234567890-=qwertyuiop[]\asdfghjkl;'zxcvbnm,./ ~!@#$%^&*()_+QWERTYUIOP{}|ASDFGHJKL:\"ZXCVBNM<>?");
allUnique("`1234567890-=qwertyuiop[]\asdfghjkl;'zxcvbnm,./ ~!@#$%^&*()_+QWERTYUIOP{}|ASDFGHJKL:\"ZXCVBNM<>? ");

function allUnique(str) {
  const chars = str.split("");
  let uniques = [];
  while (chars.length > 0) {
    const letter = chars.pop();
    if (uniques.indexOf(letter) >= 0) {
      return false;
    }
    uniques.push(letter);
  }
  return true;
}

allUnique("abcdefghijklmnopqrstuvwxyz 1234567890");
allUnique("Jan Honza Pozivil");
allUnique("`1234567890-=qwertyuiop[]\asdfghjkl;'zxcvbnm,./ ~!@#$%^&*()_+QWERTYUIOP{}|ASDFGHJKL:\"ZXCVBNM<>?");
allUnique("`1234567890-=qwertyuiop[]\asdfghjkl;'zxcvbnm,./ ~!@#$%^&*()_+QWERTYUIOP{}|ASDFGHJKL:\"ZXCVBNM<>? ");

function allUnique(str) {
  const iterator = str[Symbol.iterator]();
  let char = iterator.next();
  let uniques = "";
  while (!char.done) {
    if (uniques.includes(char.value)) {
      break;
    }
    uniques = uniques + char.value;
    char = iterator.next();
  }
  return str.length === uniques.length;
}

allUnique("abcdefghijklmnopqrstuvwxyz 1234567890");
allUnique("Jan Honza Pozivil");
allUnique("`1234567890-=qwertyuiop[]\asdfghjkl;'zxcvbnm,./ ~!@#$%^&*()_+QWERTYUIOP{}|ASDFGHJKL:\"ZXCVBNM<>?");
allUnique("`1234567890-=qwertyuiop[]\asdfghjkl;'zxcvbnm,./ ~!@#$%^&*()_+QWERTYUIOP{}|ASDFGHJKL:\"ZXCVBNM<>? ");