Union as endpoint output

[jakub-msqt]

I've been looking for a similar discussion but haven't found any. Sorry if there's some already.

I need to return 304 response from an endpoint in case nothing changed, otherwise a regular object response. I can handle the logic in ResultHandler, but I'm not sure what to return from the endpoint as output. It forces object return value which is fine but it doesn't let me return e.g. empty object and non-empty object.

z.union([z.object(), z.object({ ...fields })])

[RobinTail]

@jakub-msqt , Consider either:

factory.build({
  output: z.object({
    hasNoChanges: z.literal(true),
  }).or(z.object(fields)),
});

OR

factory.build({
  output: z.object(fields).partial(), // <— makes all props optional
});

and then handle it accordingly in a ResultHandler.
First variant might be easier to handle thanx to explicit hasNoChanges in output.

Your z.union() is also fine.

but it doesn't let me return e.g. empty object and non-empty object.

I'm not sure I get this. How exactly it does not let you? I didn't have any issues with your code sample.

[jakub-msqt]

@RobinTail any idea, please? This one is quite annoying.

[RobinTail]

@RobinTail any idea, please? This one is quite annoying.

z.looseObject({}).or(z.object(fields))

[jakub-msqt]

Well, I need to somehow match the response to the status code in ResultHandler. Empty object can be a valid 2xx response, not 304. Therefore, z.looseObject({ notModified: z.literal(true) }).or(z.object(fields)) makes more sense but TS gives error in this case.

[jakub-msqt]

z.union doesn't work either even with looseObjects.

[RobinTail]

@jakub-msqt