Elixir Tips & Tricks: Part 1

During my dwelling in Elixir I've gathered quite a few nifty tips and tricks.
I'm writing them down for a personal cookbook, but I hope it will help to spark interest in a platform. Here we go.

Ecto Datetime Helpers #

Let's start with Ecto. Not so long ago, I've discovered
Ecto's datetime query api.

I'm talking about next functions:

Date/time intervals: datetime_add/3, date_add/3, from_now/2, ago/2

What one can do with them:

from s in Subscriptions, where s.expires_at < from_now(1, "week")
# or
from p in Post, where: p.published_at > ago(3, "month")

Complete list of supported intervals: year, month, week, day, hour,
minute, second, millisecond, and microsecond.

It definitely should save a couple of keystrokes which in turn makes requests easier to grasp.

Interpolation in docs #

Nobody likes outdated documentation. One trick to keep docs up to date is to reduce the amount of copy-pasting with docs interpolation:

defmodule HTTPClient do
  @timeout 60_000

  @doc """
  Times out after #{@timeout} seconds
  """
  def get(url) do
  end
end

As you can see, I've directly used #{@timeout} in doc comment.

IO.ANSI #

If you ever wondered where iex got its stylish colors from, wonder no more.
The source of it is IO.ANSI module.

It's quite easy to colorize our own logs with it:

IO.puts(IO.ANSI.bright() <> "hello" <> IO.ANSI.red() <> " world")

Or one can proceed further and build reusable styles like in IO.ANSI.Docs.
Try and mimic h formatting:

IO.ANSI.Docs.print_heading("Yokoso into Elixir Documentation")

Summary #

It's not that hard to stumble upon peculiar things, even in everyday APIs. You need to be curious in the first place. That's it for today.
Share your finding with me at twitter.

You can make anything, till next time :)