How to use an "any" type with JSON Schema?

Question

I am looking at this:

https://json-schema.org/understanding-json-schema/reference/type.html

I have an object with a function property, but I don't want to set additionalProperties to true. So I want do something like:

      "properties": {
        "getHostNameSync": {
          "type": "any",   // << any
          "required": false
        }
      }

but it says my schema definition is invalid. Is there a way to include functions properties?

JSON schema cannot specify a function property - `JSON.stringify(() => {}) // => undefined` — Mulan, Jul 18 '19 at 01:44
JSON Schema is for validating JSON. How are you representing a function in JSON? — Relequestual, Jul 18 '19 at 08:07
In my case I am using a library that's using JSON schema to validate a JS object — Alexander Mills, Jul 18 '19 at 16:35
The library is very popular - AJV - https://github.com/epoberezkin/ajv — Alexander Mills, Jul 18 '19 at 16:46
@AlexanderMills why it looks like you have only 1 reputation?? — OhadR, Mar 30 '20 at 13:08

score 13 · Accepted Answer · answered Jul 18 '19 at 01:45

With JSON Schema, you don't have to specify things. The syntax is declarative and adds restrictions. So if you don't want a restriction on the type of value that's allowed, don't use the type keyword.

  "properties": {
    "getHostNameSync": {}
  }

This will allow the getHostNameSync property to be literally anything since no restrictions have been declared.

NOTE If you're using draft 6 or later, you can use true instead of {} and get the same effect.

How to use an "any" type with JSON Schema?

1 Answers1