Fix empty subscriptions page crash

Fix issue where when Twitch returns an empty page of subscribers, the
app crashes due to trying to get response.data[0].user_id where
response.data[0] is undefined

Also adds some debug logging

src/cronjobs/processSubscriptions.ts

@@ -35,9 +35,9 @@ export async function processSubscriptions(streamer: twitch.StreamerUserIdTokenP
 				var oldFirstUserid = response.data[0].user_id;
 				response = await twitch.streamerApiRequest(streamer,
 					`/subscriptions?broadcaster_id=${streamer.userid}&after=${response.pagination.cursor}&first=100`);
-				if (oldFirstUserid == response.data[0].user_id) break;
 				log(LogLevel.DEBUG,"Subscription API response:");
 				log(LogLevel.DEBUG,JSON.stringify(response,null,2));
+				if (response.data.length === 0 || oldFirstUserid === response.data[0].user_id) break;
 			} else {
 				break;
 			}
@@ -45,6 +45,7 @@ export async function processSubscriptions(streamer: twitch.StreamerUserIdTokenP
 		await dbconn.query("CALL update_scores()");
 		await dbconn.query('COMMIT');
 	} catch (e) {
+		log(LogLevel.ERROR,"cronjobs.processSubscriptions: Exception: " + e);
 		log(LogLevel.ERROR,"cronjobs.processSubscriptions: Exception thrown; rolling back");
 		await dbconn.query('ROLLBACK');
 		throw(e);

src/twitch.ts

@@ -53,6 +53,7 @@ export async function apiRequest(tokens: TokenPair, endpoint: string): Promise <
 	return fetch("https://api.twitch.tv/helix" + endpoint, { headers: headers })
 		.then(async (res: FetchResponse) => {
 			if (res.status == 200) {
+				log(LogLevel.DEBUG,"twitch.apiRequest: Request returned 200 for " + endpoint);
 				return res.json();
 			} else {
 				log(LogLevel.WARNING,"twitch.apiRequest: Failed API request (pre-refresh):");