Step 15.1: Add a party invitation method

both/methods/parties.methods.ts

@@ -0,0 +1,47 @@
+import {Parties} from '../collections/parties.collection';
+import {Email} from 'meteor/email';
+import {check} from 'meteor/check';
+import {Meteor} from 'meteor/meteor';
+
+function getContactEmail(user:Meteor.User):string {
+  if (user.emails && user.emails.length)
+    return user.emails[0].address;
+
+  return null;
+}
+
+Meteor.methods({
+  invite: function (partyId:string, userId:string) {
+    check(partyId, String);
+    check(userId, String);
+
+    let party = Parties.collection.findOne(partyId);
+
+    if (!party)
+      throw new Meteor.Error('404', 'No such party!');
+
+    if (party.public)
+      throw new Meteor.Error('400', 'That party is public. No need to invite people.');
+
+    if (party.owner !== this.userId)
+      throw new Meteor.Error('403', 'No permissions!');
+
+    if (userId !== party.owner && (party.invited || []).indexOf(userId) == -1) {
+      Parties.collection.update(partyId, {$addToSet: {invited: userId}});
+
+      let from = getContactEmail(Meteor.users.findOne(this.userId));
+      let to = getContactEmail(Meteor.users.findOne(userId));
+
+      if (Meteor.isServer && to) {
+        Email.send({
+          from: 'noreply@socially.com',
+          to: to,
+          replyTo: from || undefined,
+          subject: 'PARTY: ' + party.name,
+          text: `Hi, I just invited you to ${party.name} on Socially.
+                        \n\nCome check it out: ${Meteor.absoluteUrl()}\n`
+        });
+      }
+    }
+  }
+});