How to validate string and number using json schema

I would like to validate a schema based on either its maximum/minimum (number) OR maximumLength/minimumLength (string). I have a json form:

[
  {
    "key":"foo",  
    "title":"Test",
    "type":"string" 
  }
]

and a json schema:

    {
 "type": "object",
  "properties": {
    "foo": {
        "type": ["number","string"],
        "maxLength":2,
        "minLength":0,
        "minimum":3,
        "maximum":10
    }
  }
}

and a json model:

{
  "foo": "bar"
}

Why does this example not work with validation? The model I have is not validated to false. According to this document it is possible to have different types defined in an array, but how can we do validation based on min/max values?

Your schema is correct. The validator you are using doesn't work properly. Here is an alternative that uses anyOf instead.

{
    "type": "object",
    "properties": {
        "foo": {
            "anyOf": [
                { "$ref": "#/definitions/boundedNumber" }
                { "$ref": "#/definitions/boundedString" }
            ]
        }
    },
    "definitions": {
        "boundedString": {
            "type": "string",
            "maxLength": 2,
            "minLength": 0
        },
        "boundedNumber": {
            "type": "number",
            "minimum": 3,
            "maximum": 10
        }
    }
}

Although it is quite a bit longer, some would argue that this is actually easier to read/maintain because of the separation of the type specific keywords.