How to define an object with a veriable name in JSON Schema?

Question

I want to create a JSON schema for this JSON "pseudo-code" example:

{
    "xyz": {
        "$something": {
            "property_a": "...",
            "property_b": "...",
            "property_c": "..."
        }
    }
}

$something can be one of the following strings: foo , bar , or buz . My current schema looks like this:

{
  "xyz": {
    "id": "xyz",
    "type": "object",
    "properties": {
      "foo": {
        "id": "foo",
        "type": "object",
        "additionalProperties": false,
        "required": ["property_a"],
        "properties": {
          "property_a": {
            "id": "property_a",
            "type": "string"
          },
          "property_b": {
            "id": "property_b",
            "type": "string"
          },
          "property_c": {
            "id": "property_a",
            "type": "string"
          }
        }
      },
      "bar": {
        ... copy&paste foo
      },
      "buz": {
        ... copy&paste foo
      }
    }
  }
}

It's working, but it's a lot duplicated code. So I'm looking for a more elegant way for implementing it.

How to define a list of values (lie enum ) allowed as name for a property in JSON Schema?

Answer 1

patternProperties works like properties, except the keys of the object are regular expressions.

https://tools.ietf.org/html/draft-handrews-json-schema-validation-01#section-6.5.5

An example from the Understanding JSON Schema site

{
  "type": "object",
  "patternProperties": {
    "^S_": { "type": "string" },
    "^I_": { "type": "integer" }
  },
  "additionalProperties": false
}

In this example, any additional properties whose names start with the prefix S_ must be strings, and any with the prefix I_ must be integers. Any properties explicitly defined in the properties keyword are also accepted, and any additional properties that do not match either regular expression are forbidden.