Toples quiz Meizu

const rusToEng = {'а':'f','б':',','в':'d','г':'u','д':'l','е':'t','ё':'`','ж':';','з':'p','и':'b','й':'q','к':'r','л':'k','м':'v','н':'y','о':'j','п':'g','р':'h','с':'c','т':'n','у':'e','ф':'a','х':'[','ц':'w','ч':'x','ш':'i','щ':'o','ъ':']','ы':'s','ь':'m','э':'\'','ю':'.','я':'z','А':'F','Б':'<','В':'D','Г':'U','Д':'L','Е':'T','Ё':'~','Ж':':','З':'P','И':'B','Й':'Q','К':'R','Л':'K','М':'V','Н':'Y','О':'J','П':'G','Р':'H','С':'C','Т':'N','У':'E','Ф':'A','Х':'{','Ц':'W','Ч':'X','Ш':'I','Щ':'O','Ъ':'}','Ы':'S','Ь':'M','Э':'"','Ю':'>','Я':'Z',' ':' '};
const engToRus = {'f':'а',',':'б','d':'в','u':'г','l':'д','t':'е','`':'ё',';':'ж','p':'з','b':'и','q':'й','r':'к','k':'л','v':'м','y':'н','j':'о','g':'п','h':'р','c':'с','n':'т','e':'у','a':'ф','[':'х','w':'ц','x':'ч','i':'ш','o':'щ',']':'ъ','s':'ы','m':'ь','\'':'э','.':'ю','z':'я','F':'А','<':'Б','D':'В','U':'Г','L':'Д','T':'Е','~':'Ё',':':'Ж','P':'З','B':'И','Q':'Й','R':'К','K':'Л','V':'М','Y':'Н','J':'О','G':'П','H':'Р','C':'С','N':'Т','E':'У','A':'Ф','{':'Х','W':'Ц','X':'Ч','I':'Ш','O':'Щ','}':'Ъ','S':'Ы','M':'Ь','"':'Э','>':'Ю','Z':'Я',' ':' '};

const YanCode = 'ПЗМКЦ ОЦЪЫЛМ ТСЖГУСН РГ РСЕЮМ ЁСЖ';

const decode = (plaintext, shiftAmount) => {
    return [].reduce.call(plaintext, (result, current, index) => {
        let plainCharacter = plaintext.charCodeAt(index);
        return result + String.fromCharCode(plainCharacter + shiftAmount);
    }, '');
};

const changeKeyboardLayout = (code, keyboardCharMap) => {
    return [].reduce.call(code, (result, current) => {
        return result + keyboardCharMap[current];
    }, '');
};

// for (let i = 1; i < 50; i++) {
//     console.log(decode(YanCode, i));
//     console.log(decode(YanCode, -i));
// }
console.log(decode(YanCode, -3));