Determining what schema an array element should validate against - sgpinkus/json-schema GitHub Wiki

NOTE: This algorithm was included in Draft 04. Adding the more verbose wording to the web site is tracked at https://github.com/json-schema-org/json-schema-org.github.io/issues/25

For one array element, the schema which this element must validate against depends on its index in the array and the following keywords:

• items,
• additionalItems.

NOTE: array indices start at 0.

If items is absent, its default value is the empty schema. Which means all elements are valid. The end ;)

In this case, all elements of the array instance MUST be valid against the items keyword value, which is a JSON Schema.

If this is an array, then the schema is determined by the index of the array element to validate. There are two possibilities:

In this case, the element MUST be valid against the schema found at the given index in the items array.

In this case, it depends on the value of additionalItems:

This is equivalent to additionalItems being an empty schema, which means the element always validates successfully.

If it is an object, then by the rules, it is a valid JSON Schema. In this case, the element MUST validate successfully against that schema.