One idea per line

Lately, I’m doing a weird thing when writing Ruby code. I’m trying to only put one idea or action per line. I’m not sure about it yet.

Here’s what a method to fetch item-y things might look like:

def fetch_items(options={})
  limit = options.fetch(:limit)
  timestamp = options.fetch(:timestamp)
  paged_helper = PagedHelper
  client = OurHttpClient

  responses = paged_helper.
    new(limit, timestamp).
    fetch_pages { |params| client.get(params) }

  responses.
    map { |r| JSON.parse(r) }.
    map { |h| ItemCollection.new(h) }.
    map { |ic| ic.items }.
    flatten
end

For the sake of comparison, here’s how I may have written that method a couple years ago:

def fetch_items(options={})
  helper = PagedHelper.new(limit, timestamp)
  responses = helper.fetch_pages { |params| OurHttpClient.get(params) }

  responses.map { |r| ItemCollection.new(JSON.parse(r)).items }.flatten
end

I like that the pace of reading the first example is even. You don’t arrive upon some monster line of code that does a multiple things. You don’t have to unpack what’s happening in a situation where you’re calling f(g(h(some_args))). It makes moving lines of code around much simpler because each one is only dependent on what comes before, and not what happens inside. It’s a little easier to write a three-part method, which I really like.

But still, I hesitate. My methods end up about 50% longer. Breaking up the Enumerable transformations into multiple loops instead of one loop doing a bunch of work is probably pretty slow. I have to come up with a lot of names (which is, I think a net good), some of which end up a little redundant.

I’ll let you know how it goes. It may not even survive code review, who knows!