Why? 🤷

We found ourselves copy-pasting a few useful "helper" functions across our Elixir projects ...
it wasn't "DRY", so we created this library.

What? 💭

A library of useful functions that we reach for when building Elixir Apps.

Who? 👤

This library is used in our various Elixir / Phoenix apps.
As with everything we do it's Open Source, Tested and Documented so that anyone can benefit from it.

How? 💻

Install ⬇️

Install by adding useful to your list of dependencies in mix.exs:

def deps do
  [
    {:useful, "~> 1.0.8"}
  ]
end

Function Reference

atomize_map_keys/1

Converts a Map that has strings as keys (or mixed keys) to have only atom keys. e.g:

# map that has different types of keys:
my_map = %{"name" => "Alex", id: 1}
Useful.atomize_map_keys(my_map)
%{name: Alex, id: 1}

Works recursively for deeply nested maps:

person = %{"name" => "Alex", id: 1, details: %{"age" => 17, height: 185}}
Useful.atomize_map_keys(person)
%{name: Alex, id: 1, details: %{age: 17, height: 185}}

flatten_map/1

Flatten a Map of any depth/nesting:

iex> map = %{name: "alex", data: %{age: 17, height: 185}}
iex> Useful.flatten_map(map)
%{data__age: 17, data__height: 185, name: "alex"}

Note: flatten_map/1 converts all Map keys to Atom as it's easier to work with atoms as keys e.g: map.person__name instead of map["person__name"]. We use the __ (double underscore) as the delimiter for the keys of nested maps, because if we attempt to use . (period character) we get an error:

iex(1)> :a.b
** (UndefinedFunctionError) function :a.b/0 is undefined (module :a is not available)
    :a.b()

stringify_tuple/1

Stringify a tuple of any length; useful in debugging.

iex> tuple = {:ok, :example}
iex> Useful.stringify_tuple(tuple)
"ok: example"

typeof/1

Returns the type of a variable, e.g: "function" or "integer" Inspired by typeof from JavaScript land.

iex> myvar = 42
iex> Useful.typeof(myvar)
"integer"

empty_dir_contents/1

Empties the directory (+deletes all files and any nested directories_) recursively, but does not delete the actual directory. This is useful when you want to reset a directory, e.g. when testing.

iex> dir = "tmp" # contains lots of sub directories and files
iex> Useful.empty_dir_contents(dir)
{:ok, dir}

Docs 📜

Detailed docs available at: https://hexdocs.pm/useful/Useful.html

Help Us Help You! 🙏

If you need a specific helper function or utility (e.g: something you found useful in a different programming language), please open an issue so that we can all benefit from useful functions.

Thanks!