else : Schema
else
SchemaWhen if is present, and the instance fails to validate against its subschema, then validation succeeds if the instance successfully validates against this keyword’s subschema.
| Value |
This keyword must be set to a valid JSON Schema
Hint: Use the jsonschema metaschema and jsonschema lint commands to catch keywords set to invalid values
|
|---|---|
| Kind | Applicator |
| Applies To | Any |
| Base Dialect | 2019-09 |
| Changed In | None |
| Introduced In | Draft 7 |
| Vocabulary | Applicator |
| Specification | https://json-schema.org/draft/2019-09/draft-handrews-json-schema-02#rfc.section.9.2.2.3 |
| Metaschema | https://json-schema.org/draft/2019-09/meta/applicator |
| Official Tests | draft2019-09/if-then-else.json |
| Default |
{}
|
| Annotation | None |
| Affected By |
|
| Affects | None |
| Also See |
|
The else keyword restricts instances to validate against the given subschema if the if sibling keyword failed to validate against the instance.
Common Pitfall
This keyword has no effect if the if keyword is not declared within the same
subschema.
Best Practice
The if,
then, and else keywords can be thought of as imperative
variants of the anyOf keyword,
and both approaches are equally capable of describing arbitrary conditions.
Choose the one that more elegantly describes your desired
constraints.
Examples
A schema that constrains numeric instances to be positive when they are odd numbers
Schema
{
"$schema": "https://json-schema.org/draft/2019-09/schema",
"if": { "multipleOf": 2 },
"else": { "minimum": 0 }
}
Valid
An even number value that is positive is valid
Instance
10
Valid
An even number value that is negative is valid
Instance
-2
Valid
An odd number value that is positive is valid
Instance
7
Invalid
An odd number value that is negative is invalid
Instance
-3
Valid
A non-number value is valid
Instance
"Hello World"
A schema that emits a simple annotation when a numeric value is odd
Schema
{
"$schema": "https://json-schema.org/draft/2019-09/schema",
"if": { "multipleOf": 2 },
"else": { "title": "The value is an odd number" }
}
Valid
An odd number value is valid and emits an annotation
Instance
7
Annotations
{ "keyword": "/else/title", "instance": "", "value": [ "The value is an odd number" ] }
Valid
An even number value is valid but does not emit an annotation
Instance
6