res.Datas[i]interface{}
if t, ok := res.Datas[i].(time.Time); ok { 
    // it is of type time.Time 
    // t is of type time.Time, you can use it so 
} else { 
    // not of type time.Time, or it is nil 
} 
time.Timetime.Time
if _, ok := res.Datas[i].(time.Time); ok { 
    // it is of type time.Time 
} else { 
    // not of type time.Time, or it is nil 
} 
time.Time*time.Timetime.Time