Running a block code only with a specific Mix.env

elixir_run_for_envs.md

Ever found yourself writing code like this?

case Mix.env() do
  :prod -> do_something1()
  :dev  -> do_something2()
  :test -> do_something3()
end

I wrote a macro to solve this annoying use case:

MyApp.MyModule do
  import RunForEnvs, only: [run_for_envs: 2]
  
  run_for_envs [:dev] do
    do_something2()
  end
end

run_for_envs.ex

defmodule RunForEnvs do
  @doc """
  A macro that runs the `block` if the current `Mix.env` is inside passed `envs`.
  """
  defmacro run_for_envs(envs, block) do
    quote do
      if (Mix.env in unquote(envs)), do: unquote(block)
    end
  end
end