[](https://github.com/rudebono/absinthe_one_of/actions/workflows/ci.yaml)
# Absinthe one_of
Support an Input Union Type System Directive in Absinthe.
## Inspiration
This package was inspired by an article written by [Maarten Van Vliet](https://github.com/maartenvanvliet).
You can read the original article [Creating an Input Union Type System Directive in Absinthe](https://maartenvanvliet.nl/2022/04/28/absinthe_input_union/).
## Key Improvements
- **Nested Objects**: Allows for `one_of` validation within nested object structures.
- **Nested List Objects**: Supports `one_of` validation within nested lists of objects.
## Installation
Add `:absinthe_one_of` to your list of dependencies in `mix.exs`:
```elixir
def deps() do
[
{:absinthe_one_of, "~> 1.1"}
]
end
```
## Usage
### Step 1: Define Schema
Create a schema module and define your types, including the `@prototype_schema AbsintheOneOf.Directive`:
```elixir
defmodule YourWebApp.Schema do
use Absinthe.Schema
@prototype_schema AbsintheOneOf.Directive
query do
...
end
mutation do
...
end
subscription do
...
end
...
input_object(:one_of_input) do
directive(:one_of)
field(:a, :a_input)
field(:b, :b_input)
end
input_object(:a_input) do
...
end
input_object(:b_input) do
...
end
end
```
### Step 2: Setup Absinthe Pipeline
Configure the Absinthe pipeline to include the `absinthe_one_of` phase:
```elixir
defmodule YourWebApp.Endpoint do
use YourWebApp, :router
...
def pipeline(config, pipeline_opts) do
config.schema_mod
|> Absinthe.Pipeline.for_document(pipeline_opts)
|> Absinthe.Pipeline.insert_after(
Absinthe.Phase.Document.Validation.OnlyOneSubscription,
AbsintheOneOf.Phase
)
end
end
```
### Step 3: Testing
To write tests for your implementation, you can refer to the example tests provided in `test/absinthe_one_of_test.exs`. These tests demonstrate how to validate the functionality of the one_of directive and ensure that only one field is non-null among several options.
## License
This project is licensed under the MIT License - see the `LICENSE` file for details.
