Support boolean values for additionalProperties

[cyco130]

The additionalProperties property of an object should be either a boolean value or a schema that additional object properties will be validated against. While trying out as-typed npm package as a potential replacement for json-schema-to-typescript package, I've noticed that as-typed doesn't currently support additionalProperties: false. This PR implements partial support for such usage.

Actually, the default value for additionalProperties should be true and json-schema-to-typescript types the following schema:

{
	type: "object",
	properties: {
		s: { type: "string" },
		n: { type: "number" },
	},
}

like this:

{
	s: string,
	n: number,
	[k: string]: any;
}

and removes the [k: string] key only if additionalProperties is false which is technically more correct. But implementing it this way breaks almost all tests so I believe what I've done is an acceptable middle ground for the time being.

[cyco130]

PS: I can fix the linting problems if you're interested in this idea at all. Awesome work BTW.

[lbguilherme]

Hi @cyco130, thanks for this.

I believe additionalProperties should default to false for us (as you did) even if it deviates from the specification. I agree with your changes as they are.

Could you fix the linter?

[cyco130]

@lbguilherme Thanks for the feedback. I will fix the linting errors as soon as I got the time (this weekend probably).

[lbguilherme]

@cyco130 Thanks for this. I ended up merging as-is and fixing with a followup commit.

[cyco130]

@lbguilherme Sorry I failed to finish it up before you did. Thank you for merging.