Support pattern properties in object schemas

[dmosorast]

JSON Schema supports object schemas having the keys additionalProperties and patternProperties described in the Draft 4 validation document here.

Maintained

• Empty object schemas still validate against anything

Added

patternProperties

PatternProperties are a JSON object of the form {"regex_pattern": {...schema...}}. For example, a simple "catch-all" schema would look like this:

{
    "type": "object",
    "patternProperties": {
        ".+": {},
        ...
    }
}

This is useful in the event that you want the schema to validate against all keys, but override using properties for more specific types (like date-times).

Principles

• properties takes precedence
• An empty properties and patternProperties is treated as an empty schema and validates against all
• Regex ordering cannot be guaranteed (since the JSON Schema spec says "object" explicitly), so regexes should be distinct as possible for mixing types, to be deterministic