Add complete handler to Subscription, to handle the case when the ser…

[sujeetsr]

Handle finite subscriptions
(apollographql/subscriptions-transport-ws#471)

Depends on
apollographql/apollo-client#4290

@hwillson - please review.

[sujeetsr]

Sample client and server app to test this: https://github.com/sujeetsr/subscriptions-example

[hwillson]

Thanks for this @sujeetsr! Just a few small changes, then we should be pretty close here. If you're up for adding a test, similar to

react-apollo/test/client/Subscription.test.tsx

Lines 101 to 131 in 8204605

	it('calls onSubscriptionData if given', done => {
	jest.useFakeTimers();
	let count = 0;
	const Component = () => (
	<Subscription
	subscription={subscription}
	onSubscriptionData={opts => {
	expect(opts.client).toBeInstanceOf(ApolloClient);
	const { data } = opts.subscriptionData;
	expect(data).toEqual(results[count].result.data);
	if (count === 3) done();
	count++;
	}}
	/>
	);
	wrapper = mount(
	<ApolloProvider client={client}>
	<Component />
	</ApolloProvider>,
	);
	const interval = setInterval(() => {
	link.simulateResult(results[count]);
	if (count >= 3) clearInterval(interval);
	}, 10);
	jest.runTimersToTime(40);
	});

that would be great as well. If not, not worries - just let me know and I'll add it in (and add onSubscriptionComplete to the docs). Thanks!

[hwillson]

Thanks for working on this @sujeetsr!

[sujeetsr]

@hwillson thanks for merging!