Add "objectIncluding" / additionalProperties support

I’ve just read in https://github.com/aldeed/meteor-simple-schema/issues/407 that I can define an object as blackbox and add fields that should be required.

Has this behavior changed lately? Because according to the ticket I referenced above, the following code should throw an error, right?

new SimpleSchema({
  test: {
    type: Object,
    blackbox: true,
  },
  'test.foo': {
    type: String,
  },
}).validate({
  test: { bar: 'bar' },
});

[aldeed]

@SimonSimCity Here’s what I’m thinking:

Borrowing from JSONSchema, add an additionalProperties option for the SimpleSchema constructor. Unlike JSONSchema, it would be false by default for backwards compatibility.

Example of schema requiring a string name and allowing anything else unvalidated:

new SimpleSchema({ name: String }, {
  additionalProperties: true
});

Example of this as a subschema:

const itemSchema = new SimpleSchema({ name: String }, {
  additionalProperties: true
});

new SimpleSchema({
  foo: String,
  items: [itemSchema]
});

Example where all of the additional props have to have string values with at least 2 characters:

new SimpleSchema({ name: String }, {
  additionalProperties: {
    type: String,
    min: 2
  }
});

I think this is the best combination of flexibility and easy implementation.

The proposal in aldeed/meteor-simple-schema#244 goes beyond this and is much harder to implement. I think the additionalProperties approach should be fairly easy, but won’t know for sure until someone gives it a shot.

[SimonSimCity]

I mentioned this here because you were borrowing a property from JSON Schema, but your implementation would be quite different from it. If you say that you’d borrow it for this use-case I’d also rather use it the way it’s used there in order to avoid confusion. Another option would be not to link it to the JSON Schema.