Json Schema dependency on outer field - jsonschema

Question

Given a json structure like this
{
"name": "John Doe",
"billing_address": "123 main st",
"payment_details":{"credit_card": 55555555}
}
I need to make 'billing_address' a required field if payment_details.credit_card exists.
I've started from this example that achieves so if both fields were at the same level of nesting
{
"type": "object",
"properties": {
"name": { "type": "string" },
"credit_card": { "type": "number" }
},
"required": ["name"],
"dependencies": {
"credit_card": {
"properties": {
"billing_address": { "type": "string" }
},
"required": ["billing_address"]
}
}
}
However, what is the syntax to require this field that is one level above the dependant field?

Answer 1

That's too complicated for 'dependencies', so we go back to an if/then/else clause for that. We place these keywords at the top level, where the required field needs to be. In pseudocode: "if there is a payment_details property present, and it has a credit_card property, then require billing_address."
{
...,
"if": {
"type": "object",
"required": [ "payment_details" ],
"properties": {
"payment_details": {
"type": "object",
"required": [ "credit_card" ]
}
},
"then": {
"type": "object",
"required": [ "billing_address" ]
}
}
Note that the "type" and "required" keywords are required here -- as data of different types (for example an array) will cause object-specific keywords like "properties" and "required" to always evaluate to true.

Answer 2

thanks Ether! this worked, but only after adding the credit card as a property, in the if section.
the full if statement looks like this
"if": {
"type": "object",
"required": ["payment_details"],
"properties": {
"payment_details": {
"type": "object",
"properties": {
"credit_card": {}
},
"required": ["credit_card"]
}}},
the full json schema looks like this
{
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object",
"properties": {
"name": {
"type": "string"
},
"billing_address": {
"type": "string"
},
"payment_details": {
"type": "object",
"properties": {
"credit_card": {
"type": "integer"
}
}
}
}
,
"if": {
"type": "object",
"required": ["payment_details"],
"properties": {
"payment_details": {
"type": "object",
"properties": {
"credit_card": {}
},
"required": ["credit_card"]
}}},
"then": {
"type": "object",
"required": [ "billing_address" ]
}
}