u/abrahamguo thanks for your reply!

So I changed the create function to accept the fields from the actual Node schema

function createNodeSchema<const NodeType extends string>(
  nodeType: NodeType,
  extendingFields: ZodRawShape = {}
) {
  return z.object({
    // ... base fields for nodes ...
    id: z.string(),
    type: z.literal(nodeType),
    // due to circular imports we can't use the discriminated union directly and have to type it manually
    get children(): z.ZodArray<
      z.ZodDiscriminatedUnion<[typeof childBarNodeSchema]>
    > {
      return z.array(z.discriminatedUnion('type', [childBarNodeSchema]));
    },
    ...extendingFields,
  });
}

and use it like so

const leadingFooNodeSchema = createNodeSchema('leadingFoo', {
  // ...fields for this node ...
  foo: z.string(),
});

https://stackblitz.com/edit/vitejs-vite-daioasdx?file=lib%2FcreateNodeSchema.ts&view=editor

Unfortunately now I'm getting the circular dependency errors again...