This is my first post on a series regarding code reading; read this for more information. I picked up Dotenv to start with this adventure.

I started with the dotenv.rb

require 'dotenv/parser'
require 'dotenv/environment'

module Dotenv
  def self.load(*filenames)
    with(*filenames) { |f| if File.exist?(f) }

  # same as `load`, but raises Errno::ENOENT if any files don't exist
  def self.load!(*filenames)
    with(*filenames) { |f| }

  # same as `load`, but will override existing values in `ENV`
  def self.overload(*filenames)
    with(*filenames) { |f|! if File.exist?(f) }


  def self.with(*filenames, &block)
    filenames << '.env' if filenames.empty?

    filenames.inject({}) do |hash, filename|
      filename = File.expand_path filename
      hash.merge( || {})

What did I learn from this piece of code?

The most tricky part would be the method with the inject code, but reading it closer was easy to figure out. It’s creating a new hash with the executed code from the blocks above. Also it have a good trick for guarding against nil using the || {} construct.

How was the experience?

Actually at it was so small piece of code, I ended up feeling good about doing this and wanted to keep on it, but I just thought to myself that I think is better to start small and keep moving into a bigger amount of time later on; I really don’t want to spoil the habit before starting on it ;-)