CODEWITHSUNDEEP
jsonjsonschema
CyberMew
CyberMew

Reputation: 1421

How to specify JSON Schema if array is not required when there are no items in it?

Say I have some json data like this:

{
    "quantity": 3,
    "modifiers": [{}]
}

I do not want modifiers to be present if there is no intent of adding objects into modifiers.

This should be the correct way if there are no modifiers:

{
    "quantity": 3,
}

and this should be correct with modifiers:

{
    "quantity": 3,
    "modifiers": [{
        "testing": "some data here"
    }]
}

How would I structure the JSON Schema to validate the above-most example to be incorrect?

edit: Example of JSON Schema for the above examples:

{
    "type": "object",
    "properties": {
        "quantity": {
            "type": "integer",
            "minimum": 1
        },
        "modifiers": {
            "type": "array",
            "items": {
                "type": "object",
                "properties": {
                    "testing": {
                        "type": "string"
                    }
                }
            },
            "minItems": 1
        }
    },
    "required": [
        "quantity"
    ]
}

Upvotes: 2

Views: 1676

Answers (2)

Jason Desrosiers
Jason Desrosiers

Reputation: 24479

You're only missing one thing. Just add "minProperties": 1 at /properties/modifiers/items.

{
    "type": "object",
    "properties": {
        "quantity": {
            "type": "integer",
            "minimum": 1
        },
        "modifiers": {
            "type": "array",
            "items": {
                "type": "object",
                "properties": {
                    "testing": {
                        "type": "string"
                    }
                },
                "minProperties": 1
            },
            "minItems": 1
        }
    },
    "required": [
        "quantity"
    ]
}

Upvotes: 2

CyberMew
CyberMew

Reputation: 1421

(Draft 7 only) To not allow an array to be empty if present, do this:

  "if": {
    "required": [
      "modifiers"
    ]
  },
  "then": {
    "properties": {
      "modifiers": {
        "minItems": 1
      }
    }
  }

This will ensure that this is invalid:

{
    "quantity" : 1,
      "modifiers":[]
}

However note that the following json would be valid:

{
    "quantity" : 1,
      "modifiers":[{}]
}

If you don't want that, then make sure to include the appropriate required field. This would be how the final schema look like based on the given example/schema above:

{
  "type": "object",
  "properties": {
    "quantity": {
      "type": "integer",
      "minimum": 1
    },
    "modifiers": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "testing": {
            "type": "string"
          }
        },
        "required": [
          "testing"
        ]
      },
      "minItems": 1
    }
  },
  "required": [
    "quantity"
  ],
  "if": {
    "required": [
      "modifiers"
    ]
  },
  "then": {
    "properties": {
      "modifiers": {
        "minItems": 1
      }
    }
  }
}

Now, this would also be invalid:

{
    "quantity" : 1,
      "modifiers":[{}]
}

And this would be valid:

{
    "quantity" : 1,
      "modifiers":[{"testing":"343"}]
}

Upvotes: 2

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