CODEWITHSUNDEEP
jsonvalidationjsonschema
Ben Afleek
Ben Afleek

Reputation: 103

How to make a required property if another property is empty and vice versa, in the JSON Schema

My current json schema definition is like this

{
    "type": "object",
    "properties": {
        "name": {
            "type": "string",
            "minLength": 1
        },
        "description": {
            "type": "string",
            "minLength": 1
        },
        "input": {
            "type": "array",
            "items": {
                "type": "object",
                "properties": {
                    "name": {
                        "type": "string"
                    },
                    "description": {
                        "type": "string"
                    },
                    "type": {
                        "type": "string"
                    }
                },
                "required": ["name", "description", "type"]
            }
        },
        "output": {
            "type": "array",
            "maxItems": 1,
            "items": {
                "type": "object",
                "properties": {
                    "description": {
                        "type": "string",
                        "minLength": 1
                    },
                    "type": {
                        "type": "string"
                    }
                },
                "required": ["description", "type"]
            }
        }
    },
    "required": ["name", "description"]
}

So I need to validate the scheme for the following conditions:

  1. If input array and output array are empty, both must be required;
  2. If the input array is not empty, then the output array should not be required;
  3. If the output array is not empty, then the input array should not be required;

Thank you in advance.

Upvotes: 1

Views: 1029

Answers (2)

Ethan
Ethan

Reputation: 725

it seems like all three of your requirements are self-fulfilling in json schema.

If input array and output array are empty, both must be required

if input and output are empty arrays, they are already present, so saying they are required is redundant. sort of, "if x is present with the value [], then x must be present". Jason's schema correctly expresses the way you've phrased this, but I don't think there's any way for that schema to cause a validation error.

and Jason's answer is correct on points 2 and 3.

I'd suggest you think about some example instances you would expect to fail validation (and add them to your question here), and that will help to construct a schema that adds the proper constraints.

Upvotes: 1

Jason Desrosiers
Jason Desrosiers

Reputation: 24409

Your first condition is the only one that we need to deal with. All properties are optional by default, so your conditions 2 and 3 translate to something like, "if the input array is not empty, then do nothing".

There are a couple of ways to achieve the first condition, but I suggest the following.

"allOf": {
  "if": {
    "properties": {
      "input": { "const": [] },
      "output": { "const": [] }
    }
  },
  "then": { "required": ["input", "output"] }
}

Upvotes: 1

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