Railway

Pipe result tuples {:ok, value} all the way. Noop if the first element differs from :ok

Installation & Usage

Simply add railway to your list of dependencies in your mix.exs:

def deps do
  [
    {:railway, "~> 1.0"}
  ]
end

run mix deps.get and use Railway in your Module

defmodule MyModule do
  use Railway

  def my_func do
    "https://www.example.com/api"
    ~>> Req.get()
    ~>> Map.get(:body)
    ~>> Jason.decode()
    ~>> Map.get("results")
  end
end

How does ~>> work?

The ~>> operator introduces the value of an {:ok, value} tuple on the left-hand side as the first argument to the function call on the right-hand side.

If the tuple on the left-hand side is anything different from {:ok, value} like {:error, reason} the ~>> operator will just return the left-hand side and not execute the function call on the right.

If the expression on the left-hand side is not a tuple, the ~>> operator will behave just like |> does.

Documentation can be found at https://hexdocs.pm/railway