Suggestion: Return early from collection partial rendering if blank.

[tylerjc]

I was messing around with making a project's Jbuilder renders more efficient the other day.

I noticed that even empty collections trigger partial renders and take milliseconds for each, although they end up just returning []. For the examples below (pulled from the README):

json.array! @posts, partial: 'posts/post', as: :post

# or
json.partial! 'posts/post', collection: @posts, as: :post

# or
json.partial! partial: 'posts/post', collection: @posts, as: :post

# or
json.comments @post.comments, partial: 'comments/comment', as: :comment

Originally, I had written a little helper method in our project to optionally include the { partial:, as: } hash to the json.comments(@post.comments) call, but that seemed cumbersome to include everywhere and I wondered why this wasn't somehow handled in Jbuilder code.

I just started messing around locally and found that this seems to take care of it, but figured I'd open a discussion and see what others think, since I'm extremely knew to Jbuilder and could be missing something obvious.

Screenshots (Console Output Differences)

• Before PR changes (same collection):

• After PR changes (same collection):