function getRandomString(wishedIdLength) {
   var result           = '';
   var characters       = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789=-[]\|';
   var charactersLength = characters.length;
   for (let i = 0; i < wishedIdLength; i++ ) {
      result += characters.charAt(Math.floor(Math.random() * charactersLength));
   }
   return result;
}

console.log(getRandomString(8));