I am somewhat confused here, I primarily do C# so I am used to IEnumerable and Linq for doing this kind of stuff and you would just do .Where().Select().Average

I am somewhat confused here, I primarily do C# so I am used to IEnumerable and Linq for doing this kind of stuff and you would just do .Where().Select().Average() without worrying about intermediate memory usage. In C# you do this stuff with millions of results from a database (although you would do in the db if you can, but might be a flat file too). Linq with IEnumerable doesn't necessarily create intermediate list (js arrays) in memory unless it has to like say .OrderBy() So I basically assumed js was the same since it has generators but its seems map and filter etc don't support them yet?: https://dev.to/nestedsoftware/lazy-evaluation-in-javascript-with-generators-map-filter-and-reduce--36h5 https://dev.to/nestedsoftware/lazy-evaluation-in-javascript-... So then you get a solution like this that looks to me very confusing vs a fluent style. Please tell me I am missing something