Enumerated values

The enum keyword is used to restrict a value to a fixed set of values. It must be an array with at least one element, where each element is unique.

Below are several examples demonstrating its usage.

Basic Example: Street Light Colors

This example demonstrates how to validate that the color property of a street light is either "red", "amber", or "green".

schema

{ "properties": { "color": { "enum": ["red", "amber", "green"] } }}

data

{ "color": "red" }

compliant to schema

data

{ "color": "blue" }

not compliant to schema

Extended Example: Accepting Multiple Data Types

Enums can be used without explicitly setting a data type, allowing different types of values. In the following example, the schema is extended to include null (to represent an "off" state).

schema

{ "properties": { "color": { "enum": ["red", "amber", "green", null, 42] } }}

data

{ "color": null }

compliant to schema

data

{ "color": 42 }

compliant to schema

data

{ "color": 0 }

not compliant to schema

Additional Example: Mixed Types for Shape

schema

{ "properties": { "shape": { "enum": ["circle", "square", 1, null] } }}

data

{ "shape": "circle" }

compliant to schema

data

{ "shape": 1 }

compliant to schema

data

{ "shape": null }

compliant to schema

data

{ "shape": "triangle" }

not compliant to schema