fix(types): use CloudEvent<unknown> for typed events (#137)

* fix(types): use parameterized types for CloudEvent functions

Fixes type incompatibility with typed CloudEvent functions.

Also, sometimes `instanceof` is not enough. Also check the constructor name to ensure we're getting a CloudEvent back. (This appears to happen primarily when a function returns a `Promise<CloudEvent>` instead of a plain `CloudEvent`.

/kind fix

Signed-off-by: Lance Ball <lball@redhat.com>

lib/invoker.js

@@ -26,7 +26,7 @@ module.exports = function invoker(func) {
 
  // If the response is a CloudEvent, we need to convert it
  // to a Message first and respond with the headers/body
- if (fnReturn instanceof CloudEvent) {
+ if (fnReturn instanceof CloudEvent || fnReturn.constructor?.name === 'CloudEvent') {
  try {
  const message = HTTP.binary(fnReturn);
  payload.headers = {...payload.headers, ...message.headers};

lib/types.d.ts

@@ -5,12 +5,12 @@ import { CloudEvent } from 'cloudevents';
 /**
  * CloudEventFunction describes the function signature for a function that accepts CloudEvents.
  */
- export interface CloudEventFunction {
- (context: Context, event: CloudEvent): CloudEventFunctionReturn;
+export interface CloudEventFunction<I=never, R=unknown> {
+ (context: Context, event?: CloudEvent<I>): CloudEventFunctionReturn<R>;
 }
 
 // CloudEventFunctionReturn is the return type for a CloudEventFunction.
-export type CloudEventFunctionReturn = Promise<CloudEvent> | CloudEvent | HTTPFunctionReturn;
+export type CloudEventFunctionReturn<T=unknown> = Promise<CloudEvent<T>> | CloudEvent<T> | HTTPFunctionReturn;
 
 /**
  * HTTPFunction describes the function signature for a function that handles
@@ -50,7 +50,7 @@ export interface Context {
  httpVersion: string;
  httpVersionMajor: number;
  httpVersionMinor: number;
- cloudevent: CloudEvent;
+ cloudevent: CloudEvent<unknown>;
  cloudEventResponse(data: string|object): CloudEventResponse;
 }
 

test/types/context.test-d.ts

@@ -18,7 +18,7 @@ expectType<string>(context.method);
 expectType<string>(context.httpVersion);
 expectType<number>(context.httpVersionMajor);
 expectType<number>(context.httpVersionMinor);
-expectType<CloudEvent>(context.cloudevent);
+expectType<CloudEvent<unknown>>(context.cloudevent);
 expectAssignable<Record<string, any>|string|undefined>(context.body);
 
 // CloudEventResponse

test/types/index.test-d.ts

@@ -6,10 +6,10 @@ import { CloudEvent } from 'cloudevents';
 
 const fn: Invokable = function(
  context: Context,
- cloudevent?: CloudEvent
+ cloudevent?: CloudEvent<unknown>
 ) {
  expectType<Context>(context);
- expectType<CloudEvent|undefined>(cloudevent);
+ expectType<CloudEvent<unknown>|undefined>(cloudevent);
  return undefined;
 };