Struct v1.0.0 Struct.Cast View Source

Module to make struct instance from provided params.

You can use it standalone, without defining struct, by providing types and params to make/3.

Link to this section Summary

Types

options()

type()

types()

Functions

make(struct_or_types, params, opts \\ [])

Function to compose struct instance from params

Link to this section Types

options()

options() :: [make_map: boolean(), empty_values: [term()]]

type()

type() :: {Struct.Type.t(), Keyword.t()}

types()

types() :: %{required(atom()) => type()}

Link to this section Functions

make(struct_or_types, params, opts \\ [])

make(atom() | types(), map(), options()) ::
  {:ok, struct()} |
  {:error, term()}

Function to compose struct instance from params:

defmodule User do
  use Struct

  structure do
    field :name
  end
end

iex> make(User, %{name: "john doe"})
{:ok, %User{name: "john doe"}}

Also you can use it as standalone complex type-coercion by providing types and params:

iex> make(%{name: {:string, []}}, %{"name" => "john doe"})
{:ok, %{name: "john doe"}}

iex> make(%{age: {:integer, [default: 18]}}, %{"age" => "42"})
{:ok, %{age: 42}}

iex> make(%{age: {:integer, [default: 18]}}, %{})
{:ok, %{age: 18}}

iex> types = %{title: {:string, []}, comments: {{:array, :string}, default: []}}
iex> make(types, %{title: "article", comments: ["awesome", "great!", "whoa!"]})
{:ok, %{title: "article", comments: ["awesome", "great!", "whoa!"]}}

Options:

make_map — return result as map instead of struct, defaults to false;
empty_values — list of terms indicates empty values, defaults to [].

Example of empty_values:

iex> make(%{name: {:string, []}}, %{name: ""}, empty_values: [""])
{:error, %{name: :missing}}

iex> make(%{name: {:string, []}}, %{name: "john"}, empty_values: ["john"])
{:error, %{name: :missing}}