Add feed validity checking before adding

app/commands/add-feed.js

@@ -1,5 +1,6 @@
 const Core = require("../../discord-bot-core");
 const GetUrls = require("get-urls");
+const FeedRead = require("feed-read");
 const FeedData = require("../models/feed-data.js");
 const GuildData = require("../models/guild-data.js");
 // @ts-ignore
@@ -29,16 +30,20 @@ function invoke({ message, params, guildData, client }) {
 		});
 
 	return new Promise((resolve, reject) => {
-		//ask the user if they're happy with the details they set up, save if yes, don't if no
-		Core.util.ask(client, message.channel, message.member, "Are you happy with this (yes/no)?\n" + feedData.toString())
-			.then(responseMessage => {
-				if (responseMessage.content.toLowerCase() === "yes") {
-					guildData.feeds.push(feedData);
-					guildData.cachePastPostedLinks(message.guild)
-						.then(() => resolve("Your new feed has been saved!"));
-				}
-				else
-					reject("Your feed has not been saved, please add it again with the correct details");
-			});
+		FeedRead(feedUrl, (err, articles) => {
+			if (err)
+				return reject(`Unable to add the feed due to the following error:\n${err.message}`);
+
+			Core.util.ask(client, message.channel, message.member, "Are you happy with this (yes/no)?\n" + feedData.toString())
+				.then(responseMessage => {
+					if (responseMessage.content.toLowerCase() === "yes") {
+						guildData.feeds.push(feedData);
+						guildData.cachePastPostedLinks(message.guild)
+							.then(() => resolve("Your new feed has been saved!"));
+					}
+					else
+						reject("Your feed has not been saved, please add it again with the correct details");
+				});
+		});
 	});
 }