defmodule BridgeEx.Graphql.LanguageConventions do
@moduledoc """
This defines an adapter that supports GraphQL query documents in their
conventional (in JS) camelcase notation, while allowing the schema to be
defined using conventional (in Elixir) underscore (snakecase) notation, and
tranforming the names as needed for lookups, results, and error messages.
For example, this document:
```
{
myUser: createUser(userId: 2) {
firstName
lastName
}
}
```
Would map to an internal schema that used the following names:
* `create_user` instead of `createUser`
* `user_id` instead of `userId`
* `first_name` instead of `firstName`
* `last_name` instead of `lastName`
Likewise, the result of executing this (camelcase) query document against our
(snakecase) schema would have its names transformed back into camelcase on the
way out:
```
%{
data: %{
"myUser" => %{
"firstName" => "Joe",
"lastName" => "Black"
}
}
}
```
Note variables are a client-facing concern (they may be provided as
parameters), so variable names should match the convention of the query
document (eg, camelCase).
"""
use Absinthe.Adapter
@doc """
Converts a camelCase to snake_case
iex> to_internal_name("test", :read)
"test"
iex> to_internal_name("testTTT", :read)
"test_t_t_t"
iex> to_internal_name("testTest", :read)
"test_test"
iex> to_internal_name("testTest1", :read)
"test_test_1"
iex> to_internal_name("testTest11", :read)
"test_test_11"
iex> to_internal_name("testTest11Pippo", :read)
"test_test_11_pippo"
iex> to_internal_name("camelCase23Snake4344", :read)
"camel_case_23_snake_4344"
"""
def to_internal_name(nil, _role) do
nil
end
def to_internal_name("__" <> camelized_name, role) do
"__" <> to_internal_name(camelized_name, role)
end
def to_internal_name(camelized_name, :operation) do
camelized_name
end
def to_internal_name(camelized_name, _role) do
~r/([A-Z]|\d+)/
|> Regex.replace(camelized_name, "_\\1")
|> String.downcase()
end
defdelegate to_external_name(underscored_name, role), to: Absinthe.Adapter.LanguageConventions
end