Items object should have equal property - json

Question

I have a JSON like this:
{
"result": [
{
"name": "Adam",
"age": 22
},
{
"name": "John"
},
{
"name": "Justin",
"age": 25
}
]
}
and schema:
{
"definitions": {},
"$schema": "http://json-schema.org/draft-07/schema#",
"$id": "https://example.com/object1607582431.json",
"title": "Root",
"type": "object",
"required": [
"result"
],
"properties": {
"result": {
"$id": "#root/result",
"title": "Result",
"type": "array",
"default": [],
"items": {
"$id": "#root/result/items",
"title": "Items",
"type": "object",
"required": [
"name"
],
"properties": {
"name": {
"$id": "#root/result/items/name",
"title": "Name",
"type": "string",
"default": "",
"pattern": "^.*$"
},
"age": {
"$id": "#root/result/items/age",
"title": "Age",
"type": "integer",
"default": 0
}
}
}
}
}
}
Here age is an optional property. I am struggling to apply a rule if an optional property is present in one object then it should present in all the objects in that collection. Is there any option available for this?

Answer 1

This is actually a really good use case for the if/then construct that really can't be replicated by using a oneOf like a switch statement. (Well done.)
You're going to want to add the if/then construct to the results property subschema. If the if passes, then the then MUST also apply.
"result": {
...,
"if": {
"contains": { "required": [ "age" ] } // 1
},
"then": {
"items": { "required": [ "age" ] } // 2
}
}
If the the result object contains an item that has an age property,
Require all items to have an age property.
Edit
Full schema:
{
"definitions": {},
"$schema": "http://json-schema.org/draft-07/schema#",
"$id": "https://example.com/object1607582431.json",
"title": "Root",
"type": "object",
"required": [
"result"
],
"properties": {
"result": {
"$id": "#root/result",
"title": "Result",
"type": "array",
"default": [],
"if": { "contains": { "required": [ "age" ] } },
"then": { "items": { "required": [ "age" ] } },
"items": {
"$id": "#root/result/items",
"title": "Items",
"type": "object",
"required": [
"name"
],
"properties": {
"name": {
"$id": "#root/result/items/name",
"title": "Name",
"type": "string",
"default": "",
"pattern": "^.*$"
},
"age": {
"$id": "#root/result/items/age",
"title": "Age",
"type": "integer",
"default": 0
}
}
}
}
}
}
Instance:
{
"result": [
{
"name": "one"
},
{
"name": "two",
"age": 5
},
{
"name": "three"
}
]
}
Remove the age property or add it to the other items to get the schema to pass.