group join/leave controls in groups list page (+ helper!)

public/src/helpers.js

@@ -17,6 +17,19 @@
 		return '<meta ' + name + property + content + '/>';
 	};
 
+	// Groups helpers
+	helpers.membershipBtn = function(groupObj) {
+		if (groupObj.isMember) {
+			return '<button class="btn btn-danger" data-action="leave" data-group="' + groupObj.name + '"><i class="fa fa-times"></i> Leave Group</button>';
+		} else {
+			if (groupObj.pending) {
+				return '<button class="btn btn-warning disabled"><i class="fa fa-clock-o"></i> Invitation Pending</button>';
+			} else {
+				return '<button class="btn btn-success" data-action="join" data-group="' + groupObj.name + '"><i class="fa fa-plus"></i> Join Group</button>';
+			}
+		}
+	};
+
 	if ('undefined' !== typeof window) {
 		$(document).ready(module.exports);
 	}
@@ -26,6 +39,7 @@
 
 		templates.registerHelper('displayUsersLink', helpers.displayUsersLink);
 		templates.registerHelper('buildMetaTag', helpers.buildMetaTag);
+		templates.registerHelper('membershipBtn', helpers.membershipBtn);
 	};
 
 })('undefined' === typeof module ? {

src/controllers/groups.js

@@ -9,7 +9,8 @@ var groups = require('../groups'),
 groupsController.list = function(req, res, next) {
 	groups.list({
 		truncateUserList: true,
-		expand: true
+		expand: true,
+		uid: req.user ? req.user.uid : 0
 	}, function(err, groups) {
 		if (err) {
 			return next(err);

src/groups.js

@@ -71,7 +71,25 @@ var async = require('async'),
 			groupNames = groupNames.concat(ephemeralGroups);
 
 			async.map(groupNames, function (groupName, next) {
-				Groups.get(groupName, options, next);
+				async.waterfall([
+					async.apply(Groups.get, groupName, options),
+					function(groupObj, next) {
+						// Retrieve group membership state, if uid is passed in
+						if (!options.uid) {
+							return next(null, groupObj);
+						}
+
+						Groups.isMember(options.uid, groupName, function(err, isMember) {
+							if (err) {
+								winston.warn('[groups.list] Could not determine membership in group `' + groupName + '` for uid `' + options.uid + '`: ' + err.message);
+								return next(null, groupObj);
+							}
+
+							groupObj.isMember = isMember;
+							next(null, groupObj);
+						});
+					}
+				], next);
 			}, function (err, groups) {
 				callback(err, internals.filterGroups(groups, options));
 			});