JSON schema-based constraint specification.

Defines field types, required fields, enums, and validation rules.

Supported Types

• :string - String values
• :integer - Integer values (supports :positive constraint)
• :boolean - Boolean values (true/false)
• :number - Numeric values (integer or float)
• {:enum, values} - Enumerated values from a list
• {:array, item_spec} - Array/list of items with validation

Field Specification

Each field can have:

• type - The field type (required)
• required - Whether the field must be present (default: false)
• description - Documentation for the field (optional)
• positive - For integers, must be > 0 (optional, default: false)
• min_length - For strings, minimum length in characters (optional)
• max_length - For strings, maximum length in characters (optional)
• min - For integers/numbers, minimum value (optional)
• max - For integers/numbers, maximum value (optional)
• min_items - For arrays, minimum number of items (optional)
• max_items - For arrays, maximum number of items (optional)
• unique_items - For arrays, whether items must be unique (default: false)
• pattern - For strings, custom regex pattern (Regex.t() or string)
• format - For strings, built-in format (:email, :url, :uuid, :phone, :date)

Example

address_schema = %ExOutlines.Spec.Schema{
  fields: %{
    city: %{type: :string, required: true},
    zip_code: %{type: :string, required: true, min_length: 5}
  }
}

schema = %ExOutlines.Spec.Schema{
  fields: %{
    name: %{type: :string, required: true, description: "User's full name"},
    age: %{type: :integer, required: true, positive: true},
    role: %{type: {:enum, ["admin", "user"]}, required: false},
    active: %{type: :boolean, required: false},
    tags: %{type: {:array, %{type: :string, max_length: 20}}, max_items: 10},
    address: %{type: {:object, address_schema}, required: true}
  }
}

# Valid input with nested object
ExOutlines.Spec.validate(schema, %{
  "name" => "Alice",
  "age" => 30,
  "tags" => ["elixir"],
  "address" => %{"city" => "NYC", "zip_code" => "10001"}
})
# => {:ok, %{name: "Alice", age: 30, tags: ["elixir"], address: %{city: "NYC", zip_code: "10001"}}}

# Invalid input (missing required field)
ExOutlines.Spec.validate(schema, %{"name" => "Bob"})
# => {:error, %Diagnostics{...}}