Better error messages when oneOf/anyOf doesn't match

Consider this example:

var schema = {
    "type": "object",
    "required": ["foo", "bar"],
    "additionalProperties": false,
    "properties": {
        "foo": {
            "type": "integer"
        },
        "bar": {
            "oneOf": [{
                "type": "object",
                "required": ["id"],
                "additionalProperties": false,
                "properties": {
                    "id": {
                        "type": "integer"
                    }
                }
            }, {
                "type": null,
                "additionalProperties": false
            }]
        }
    }
};

var candidate = {
    "foo": 123,
    "bar": {
        "id": 456
    }
};

Based on the schema the candidate is valid. However, if I change the id to a string value (e.g “456”), I will get this error:

[ { field: 'data.bar',
    message: 'no (or more than one) schemas match' } ]

While the error message is not wrong, it can be more informative by saying which field has issue. The same thing can apply for missing required fields or having additional properties when it’s not allowed.

[mafintosh]

@skilledDeveloper would something like the following work:

{
  field: 'data.bar.id',
  schema: 'data.bar#anyOf[1]',
  message: 'is the wrong type'
}

Then we could add a schema identifier to subschemas as well to solve stuff like #22 as well

[adrai]

+1