Applies a function to every value of a series keeping the time stamps
TimeSeriesMap[f, tes]
TimeSeriesMap[{ncom1 -> f1, ncom2 -> f2, …}, tes]
ts = TimeSeries[{23, 34, 56}, {0}, ComponentKeys -> {"a"}]; TimeSeriesMap[f, ts]//Tabular
→ Tabular[TimeSeries[{{0, f[23]}, {1, f[34]}, {2, f[56]}}]]