Mapáil

Convert maps with string keys to an elixir struct.

Features

String keyed maps: Convert maps with string keys to a corresponding struct.
Transformations: Optionally, string manipulations can be applied to the string of the map so as to attempt to force the key to match the key of the struct. Currently, the only transformation option is conversion to snake_case.
Residual maps: Optionally, the part of the map leftover after the struct has been built can be retrieved or merged back into the returned struct.

Examples

Example (1)

Converting a map using the default settings which include coercions of keys into the snake_case format and discarding any unmatching key-value pairs.

user = %{
        "FirstName" => "John",
        "Username" => "john",
        "password" => "pass",
        "age" => 30
        }

defmodule User, do: defstruct [:first_name, :username, :password]

Mapail.map_to_struct(user, User)

{:ok, %User{
  first_name: "John",
  username: "john",
  password: "pass"
  }
}

Example (2)

Converting a map without applying any transformations so that only exact matches on key-value pairs will be used and unmatching key-value pairs will be discarded.

user = %{
        "FirstName" => "John",
        "Username" => "john",
        "password" => "pass",
        "age" => 30
        }

defmodule User, do: defstruct [:first_name, :username, :password]

Mapail.map_to_struct(user, User, transformations: [])

{:ok, %User{
  first_name: nil,
  password: "pass",
  username: nil
  }
}

Example (3)

Converting a map without applying any transformations so that only exact matches on key-value pairs will be used and unmatching key-value pairs will be returned as a separate map.

user = %{
        "FirstName" => "John",
        "Username" => "john",
        "password" => "pass",
        "age" => 30
        }

defmodule User, do: defstruct [:first_name, :username, :password]

Mapail.map_to_struct(user, User, transformations: [], rest: :true)

{:ok, %User{
  first_name: nil,
  password: "pass",
  username: nil
  },
  %{
  "FirstName" => "John",
  "Username" => "john",
  "age" => 30
  }
}

Example (4)

Converting a map using the default settings which include coercions of keys into the snake_case format and unmatching key-value pairs will be merged back into the original map under the :mapail key.

user = %{
        "FirstName" => "John",
        "Username" => "john",
        "password" => "pass",
        "age" => 30
        }

defmodule User, do: defstruct [:first_name, :username, :password]

Mapail.map_to_struct(user, User, rest: :merge)

{:ok, %{
    __struct__: User,
    first_name: "John",
    password: "pass",
    username: "john",
    mapail: %{
      "FirstName" => "John",
      "Username" => "john",
      "age" => 30
    }
  }
}

Example (5)

Converting a map without applying any transformations so that only exact matches on key-value pairs will be used and unmatching key-value pairs will be merged back into the original map under the :mapail key.

user = %{
        "FirstName" => "John",
        "Username" => "john",
        "password" => "pass",
        "age" => 30
        }

defmodule User, do: defstruct [:first_name, :username, :password]

Mapail.map_to_struct(user, User, transformations: [], rest: :merge)

{:ok, %{
    __struct__: User,
    first_name: nil,
    password: "pass",
    username: nil,
    mapail: %{
      "FirstName" => "John",
      "Username" => "john",
      "age" => 30
    },
  }
}

Documentation

Documentation can be found in the hex package manager.

Installation

The package can be installed as follows:

Add mapail to your list of dependencies in mix.exs:

def deps do
  [{:mapail, "~> 0.2"}]
end

Ensure mapail is started before your application:

def application do
  [applications: [:mapail]]
end

The package can be found in hex.

Credit

This library has a dependency on the following libraries:

Licence

MIT Licence