I'm wondering about this:
NOTE: be careful about when you use partial collections, as rendering an array with a length of 100 means we have to render 100 views. For simple collections you may inline the iteration instead of using partial collection support to decrease overhead.
So it`s not a good idea to do it like this?
<%- partial('overall_header.ejs') %>
<!-- Content of the website -->
<%- partial('overall_footer.ejs') %>
Or shouldn't I use variables and arrays in partial?
"Note" that you metioned refers to rendering partial for large arrays, as in guide:
partial('comment', comments);
Where "comments" is large array.
In your example overall_header and overall_footer are rendered just once, which is fine. No considerable overhead.