Ruby's new yield_self

Ever wrote some Elixir and loved what |> a.k.a. “the pipe” does?

Then Ruby 2.5 might be what you alway waited for. Victor Shepelev (on GitHub) wrote a genius blog post about yield_self.

Michał Łomnicki article is also very good, it helps getting a bit deeper into it.

Check out yield_self in the official Ruby docs.

# Example taken from:
# http://zverok.github.io/blog/2018-01-24-yield_self.html

# before
url = construct_url
response = Faraday.get(url)
data = JSON.parse(response.body)
id = data.dig('object', 'id') || '<undefined>'
return "server:#{id}"
# or, short yet less readable form:
return "server:" +
  (JSON.parse(Faraday.get(construct_url)).dig('object', 'id') || '<undefined>')

# after:
construct_url
  .yield_self { |url| Faraday.get(url) }
  .yield_self { |response| JSON.parse(response) }
  .dig('object', 'id').yield_self { |id| id || '<undefined>' }
  .yield_self { |id| "server:#{id}" }

Of course it takes a while to get used to. But I think this can bring some light in an otherwise complex public API of an Object.

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