Future proof JSON schema - json

Question

Is it possible to force known objects ("enemy" and "friend") to be defined while other objects are allowed?
I've added the last object {"type": "object"} to display the intended behaviour - but in reality the last object will overrule the two defined objects ("enemy" and "friend") causing any kind of object to be valid with this schema. If I remove the last object, it will allow the two objects but nothing else.
JSON schema (using array for faster testing):
{
"type": "array",
"items": {
"anyOf": [
{"$ref": "#/definitions/friend"},
{"$ref": "#/definitions/enemy"},
{"$ref": "#/definitions/future"}
]
},
"definitions": {
"friend": {
"type": "object",
"properties": {
"time": {"type": "string"},
"value": {"type": "number", "minimum": 100}
},
"required": ["time", "value"],
"additionalProperties": false
},
"enemy": {
"type": "object",
"properties": {
"enemy": {"type": "string"},
"color": {"type": "number"}
},
"required": ["enemy", "color"],
"additionalProperties": false
},
"future": {
"type": "object",
"properties": {
"time": {"type": "string"}
}, "required": ["time"],
"additionalProperties": true
}
}
}
Example JSON (top 3 should be OK, last 3 should not be OK):
[
{"time": "123", "value": 100}, <- should be valid
{"time": "1212", "value": 150}, <- should be valid
{"enemy": "bla", "color": 123}, <- should be valid
{"time": "1212", "value": 50}, <- should be invalid bcoz of "future"
{"enemy": "bla", "color": "123"}, <- shouldn't be valid bcoz of "enemy" schema
{"somethingInFuture": 123, "someFutProp": "ok"} <- should be valid
]

Answer 1

It's not very clear what you really want but you probably want to use a combination of dependencies and minProperties here. The two forms of this keyword are used here: property dependency and schema dependency. You also want at least one property to be defined, hence minProperties. So you can do something like this (note that I also factorized the common schema for color; it may, or may not, be what you want):
{
"type": "object",
"minProperties": 1,
"additionalProperties": {
"type": "string" // All properties not explicitly defined are strings
},
"properties": {
"color": { "type": "number" }
},
"dependencies": {
"enemy": "color", // property dependency
"friend": { // schema dependency
"properties": { "color": { "minimum": 50 } },
"required": [ "color" ]
}
}
}
Note that this schema still allows "enemy" and "friend" at the same time (so does your original schema). To do better, sample JSONs you want to deem valid and invalid should be provided.