Thank you for your time.
Consider if my data shows seasonal behavior, then I must pass Alpha(Base), beta(Smoothing) and gamma(Seasonality) parameter inside the holtwinder function for a better forecast. So I wanted to forecast this kind data with proper explanation in my app not just like that.
Any explanation on it isn't working will be much helpful.
So far, the Integration works well. There are two possible reasons for this error,
1) The forecasting data should be in the class of ts().
2) The forecasting data should have at least two years of data.
R.ScriptEval('library(TTR);library(forecast);data.frame(forecast(HoltWinters(ts(q$sumRain,start=c(1813), end=c(1912), frequency = 1), alpha = 0.598, beta=0, gamma=0.904), h=$(RainNumberOfYears)))[,1]', Sum(rain) as sumRain)