Referring inner properties in the IF condition - JSON Schema - jsonschema

Question

The following is a sample schema to depict the issue
{
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object",
"definitions": {
"person": {
"type": "object",
"properties": {
"age": {
"type": "string"
}
}
}
},
"properties": {
"child": {
"$ref": "#/definitions/person"
}
},
"required": [
"child"
],
"if": {
"properties": {
"person/age": {
"const": "3"
}
}
},
"then": {
"properties": {
"guardian": {
"$ref": "#/definitions/person"
}
},
"required": [
"guardian"
]
}
}
Is there a way to refer age inside the person object?
{"child":{"age":"3"}}. Should fail as guardian tag is missing
The above data should fail as the guardian object is missing.

Answer 1

Remember that if is just a regular schema validating against the instance. Just nest your properties like you would with any nested object structure.
{
"type": "object",
"properties": {
"child": {
"type": "object",
"properties": {
"age": { "const": "3" }
},
"required": ["age"]
}
},
"required": ["child"]
}
Note that the type and required keywords are necessary to not inadvertently trigger the then schema. For example, with out them, these would cause the then to trigger when you probably didn't want it to.
{}
{ "child": null }
{ "child": {} }