null

When a schema specifies a type of null, it has only one acceptable value: null.

OpenAPI 2.0 has no built-in support for null types. Redocly published a specification extension x-nullable which can be used to specify that a field value can be null.

In OpenAPI 3.0, a built-in nullable field was added.

In OpenAPI 3.1, the type accepts an array of types, and null can be added to the list of types.

Visuals

The following shows three examples for implementing null in OAS 2.0, 3.0, and 3.1.

type: object
properties:
  screen:
    type: string
    x-nullable: true

type: object
properties:
  screen:
    type: string
    nullable: true

type: object
properties:
  screen:
    type:
      - string
      - 'null'

The following image shows the schema with a string type of property that is also nullable.

Types

• SchemaProperties

const SchemaProperties: NodeType = {
  properties: {},
  additionalProperties: 'Schema',
};