anyof.json

{
  "type": "object",
  "properties": {
    "age": {
      "type": "integer",
      "title": "Age"
    },
    "items": {
      "type": "array",
      "items": {
        "type": "object",
        "anyOf": [
          {
            "properties": {
              "foo": {
                "type": "string"
              }
            }
          },
          {
            "properties": {
              "bar": {
                "type": "string"
              }
            }
          }
        ]
      }
    }
  },
  "anyOf": [
    {
      "title": "First method of identification",
      "properties": {
        "firstName": {
          "type": "string",
          "title": "First name",
          "default": "Chuck"
        },
        "lastName": {
          "type": "string",
          "title": "Last name"
        }
      }
    },
    {
      "title": "Second method of identification",
      "properties": {
        "idCode": {
          "type": "string",
          "title": "ID code"
        }
      }
    }
  ]
}