How to define an array with a fixed set of valid values?

Question

I'm having trouble defining this field in OpenAPI. I've got a schema with a field that can hold an array of zero or more strings, like this { "daysOfWeek": ["Monday", "Wednesday", "Friday"] } or this { "daysOfWeek": ["Sunday", "Monday", "Tuesday", "Wednesday"] } or this { "daysOfWeek": []}.

The following schema definition yields this warning in SwaggerHub for each enum element: enum value should conform to its schema's type.

        "SampleSchema": {
            "type": "object",
            "properties": {
                "daysOfWeek": {
                    "description": "An array of zero or more days of the week",
                    "type": "array",
                    "items": {
                        "type": "string"
                    },
                    "enum": [
                        "Sunday",
                        "Monday",
                        "Tuesday",
                        "Wednesday",
                        "Thursday",
                        "Friday",
                        "Saturday"
                    ]
                }
            }
        }

Changing items.type to "array" produces the same warning.

What is the correct way to describe a field like this in OpenAPI?

Answer 1

The enum field refers to the array items, so it should be a part of the items object:

  "SampleSchema": {
    "type": "object",
    "properties": {
      "daysOfWeek": {
        "description": "An array of zero or more days of the week",
        "type": "array",
        "items": {
          "type": "string",
          "enum": [
            "Sunday",
            "Monday",
            "Tuesday",
            "Wednesday",
            "Thursday",
            "Friday",
            "Saturday"
          ]
        }
      }
    }
  }