Add support for `t.intersection` and `t.keyof` Types

[kevin-btc]

Describe the bug
When using t.intersection and t.keyof from the io-ts library (version 2.2.20) with the polyfact SDK (version 0.1.7) in a Node.js (v19.4.0) environment, an error message saying "Unsupported type '[object Object]'." is thrown.

To Reproduce
The error can be reproduced by using the following code:

const TReference = t.type({
  name: t.string,
    category: t.keyof({
      function: null,
      method: null,
      class: null,
      type: null,
      structure: null,
      enum: null,
    }),
});

const TReferenceWithSubreferences = t.intersection([
  TReference,
  t.type({
    subreferences: t.array(TReference),
  }),
]);

Expected behavior
The expected behavior is that the types t.intersection and t.keyof should be handled without any error.

Actual behavior
The actual behavior is that an error is thrown:

Error: Unsupported type "[object Object]".
Please use one of:
        - InterfaceType (t.type)
        - ArrayType (t.array)
        - NumberType (t.number)
        - StringType (t.string)
        - BooleanType (t.boolean)

Proposed Fix

Based on the error message and provided code, it seems the internalTsio2JSON function currently doesn't support the IntersectionType and KeyofType from io-ts. A potential fix could involve adding additional checks to handle these types within the function.

Here's a preliminary suggestion on how this could be approached:

function internalTsio2JSON(type: any): any {
    // ... Existing conditions ...

    // Additional handlers for IntersectionType and KeyofType
    if (type._tag === "IntersectionType") {
        return type.types.map(internalTsio2JSON);
    }
    if (type._tag === "KeyofType") {
        return Object.keys(type.keys);
    }

    throw new Error(
        `Unsupported type "${type}".\nPlease use one of:\n\t- InterfaceType (t.type)\n\t- ArrayType (t.array)\n\t- NumberType (t.number)\n\t- StringType (t.string)\n\t- BooleanType (t.boolean)\n\t- IntersectionType (t.intersection)\n\t- KeyofType (t.keyof)\n`,
    );
}

Additional context
My project is written in TypeScript and uses io-ts for static type checking at runtime.

Thank you for looking into this issue.

[lowczarc]

#7 Resolves this issue