postTransform would be more useful with schema information

[duncanbeevers]

Description

The postTransform option is handed the ts types as they're generated from each OpenAPI schema member in transformSchemaObject.
However, although there is a 1:1 mapping between calls to the postTransform, and OpenAPI schema members, postTransform has no access to the OpenAPI schema object associated with the generated ts node.

I think postTransform would be more useful if it gave access to the schema node, and it should be added to the options argument, passed to postTransform, along with path and ctx.

Checklist

• I’m willing to open a PR (see CONTRIBUTING.md)

[duncanbeevers]

I was able to reach the schema node a bit indirectly. Rather than change the postTransform signature or modify the TransformNodeOptions, I reached the schema node by resolving the path, already present on the TransformNodeOptions.

postTransform(type: ts.TypeNode, options: openapiTS.TransformNodeOptions): ts.TypeNode {
  const schema = options.path ?
    options.ctx.resolve<openapiTS.ReferenceObject | openapiTS.SchemaObject>(options.path) :
    undefined;

  if (
    schema &&
    !("$ref" in schema) &&
    Object.hasOwn(schema, "x-my-custom-property")
  ) {
    return ts.factory.createUnionTypeNode(…);
  }

  return type;
}

It was still a bit of a chore to discover this path, but since all the necessary pieces seem to be present, perhaps this issue should be closed.

[drwpow]

Ha that’s clever! But agreed we could make this easier. We’d accept adding anything onto options (e.g. options.schema). Thanks for suggesting!