time series cross validation

[newsagent]

I have seen the source code for

https://otexts.com/fpp3/tscv.html

I was wondering if you can provide a code example that would simplify the very nice but advanced R functions behind the calculation of CV; that is a simple R code for time series cross validation

[robjhyndman]

Older and simpler code can be seen in the forecast::tscv() function: https://github.com/robjhyndman/forecast/blob/master/R/tscv.R

[newsagent]

This is very helpful link. Thank you.