maxItems : Integer
maxItems
IntegerAn array instance is valid if its size is less than, or equal to, the value of this keyword.
| Value | This keyword must be set to a zero or positive integer |
|---|---|
| Kind | Assertion |
| Applies To | Array |
| Base Dialect | 2020-12 |
| Changed In | None |
| Introduced In | Draft 1 |
| Vocabulary | Validation |
| Specification | https://json-schema.org/draft/2020-12/json-schema-validation.html#section-6.4.1 |
| Metaschema | https://json-schema.org/draft/2020-12/meta/validation |
| Official Tests | draft2020-12/maxItems.json |
| Default | None |
| Annotation | None |
| Affected By | None |
| Affects | None |
| Also See |
|
The maxItems keyword restricts array instances to consists of an inclusive
maximum numbers of items.
Best Practice
To restrict array instances to the empty array, prefer using the
const keyword instead of
setting this keyword to 0.
Remember that JSON Schema is a constraint-driven language.
Therefore, non-array instances successfully validate against this
keyword. If needed, make use of the type keyword to constraint
the accepted type accordingly.
Examples
A schema that constrains array instances to contain at most 3 items
Schema
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"maxItems": 3
}
Invalid
An array value with more than 3 items is invalid
Instance
[ 1, 2, 3, 4 ]
Valid
An array value with 3 items is valid
Instance
[ 1, true, "hello" ]
Valid
An array value with less than 3 items is valid
Instance
[ false, "foo" ]
Valid
A non-array value is valid
Instance
"Hello World"