add main post content to all topic lists

mainpost.js

//use filter:topics.get in plugin.json
//{ "hook": "filter:topics.get", "method": "addMainPostContent"}


module.addMainPostContent = function(data, callback) {
	var topics = data.topics;
	var keys = topics.map(function(topic) {
		return topic && 'topic:' + topic.tid;
	});

	db.getObjectsFields(keys, ['mainPid'], function(err, mainPids) {
		if (err) {
			return callback(err);
		}

		mainPids = mainPids.map(function(topic) {
			return topic && topic.mainPid;
		});

		posts.getPostSummaryByPids(mainPids, data.uid, {stripTags: true}, function(err, posts) {
			if (err) {
				return callback(err);
			}
			for (var i=0; i<topics.length; ++i) {
				if (topics[i]) {
					topics[i].mainPost = posts[i];
				}
			}
			callback(null, data);
		});
	});
};