docs: function fromCharCode(code, fromBase, toBase) {
    let char = -1;
    for (let i = 0; i < fromBase; i++) {
      let okCode = consts.alphabet[i].charCodeAt(0);
      if (code == okCode || (!consts.caseSensitive && code == changeCase(okCode))) {
        char = i;
        break;
      }
    }
  
    if (char < 0) throw new Error('invalid character detected');
  
    return fromNumber(char, toBase);
  }