A module to convert a simple schema to JSON Schema

Basic:

iex> schema = %{name: :string,
...>            value: {:integer, optional: true},
...>            array: [:string],
...>            map: {%{x: :integer, y: :integer}, optional: true},
...>            param: {:any, optional: true}}
iex> SimpleSchema.Schema.to_json_schema(schema)
%{
  "type" => "object",
  "required" => ["array", "name"],
  "additionalProperties" => false,
  "properties" => %{
    "name" => %{"type" => "string"},
    "value" => %{"type" => "integer"},
    "array" => %{
      "type" => "array",
      "items" => %{"type" => "string"},
    },
    "map" => %{
      "type" => "object",
      "required" => ["x", "y"],
      "additionalProperties" => false,
      "properties" => %{
        "x" => %{"type" => "integer"},
        "y" => %{"type" => "integer"},
      },
    },
    "param" => %{
      "type" => ["array", "boolean", "integer", "null", "number", "object", "string"],
    },
  },
}

With restrictions:

iex> schema = %{name: {:string, min_length: 8},
...>            value: {:integer, optional: true, nullable: true, maximum: 10},
...>            array: {[{:string, enum: ["aaa", "bbb"]}], min_items: 1}}
iex> SimpleSchema.Schema.to_json_schema(schema)
%{
  "type" => "object",
  "required" => ["array", "name"],
  "additionalProperties" => false,
  "properties" => %{
    "name" => %{
      "type" => "string",
      "minLength" => 8,
    },
    "value" => %{
      "type" => ["integer", "null"],
      "maximum" => 10,
    },
    "array" => %{
      "type" => "array",
      "minItems" => 1,
      "items" => %{
        "type" => "string",
        "enum" => [
          "aaa",
          "bbb",
        ],
      }
    },
  },
}