今天由于要寫一個工具轉碼處理字符串，于是就沒有導入自己的pod，結果字符串一直出現<object returned empty description>，各種判斷沒有效果，也不想導入自己的pod，因為項目太小了用pods太小題大做了，于是就在網上找了找，結果真的是都不管用，，于是還是秒自己之前給NSString寫的一個分類，分分鐘見效

/// 是否為空或者是空格
- (BOOL)isEmpty ///< 是否為空或者是空格
{
    
    NSString * newSelf = [self stringByReplacingOccurrencesOfString:@" " withString:@""];
    if(nil == self
       || self.length ==0
       || [self isEqualToString:@""]
       || [self isEqualToString:@"<null>"]
       || [self isEqualToString:@"(null)"]
       || [self isEqualToString:@"null"]
       || newSelf.length ==0
       || [newSelf isEqualToString:@""]
       || [newSelf isEqualToString:@"<null>"]
       || [newSelf isEqualToString:@"(null)"]
       || [newSelf isEqualToString:@"null"]
       || [self isKindOfClass:[NSNull class]] ){
        
        return YES;
        
    }else{
        // <object returned empty description> 會來這里
        NSCharacterSet *set = [NSCharacterSet whitespaceAndNewlineCharacterSet];
        NSString *trimedString = [self stringByTrimmingCharactersInSet:set];
        
        return [trimedString isEqualToString: @""];
    }
    
    return NO;
}