Custom News feed web part for SharePoint site feed app.

Use the below code to populate and post the feed in site feed app in SharePoint 2013.

Note :Enable/Activate Site feed feature in the list of available features

var clientContext;
var feedManager;
var allfeeds;
var website;
var websiteurl = "";
function populatePosts() {
    try {
        SP.SOD.executeFunc('sp.js', 'SP.ClientContext', sharePointReady);
    }
    catch (ex) {
        alert(ex);
    }
}

function sharePointReady() {
    clientContext = SP.ClientContext.get_current();
    website = clientContext.get_web();
    clientContext.load(website);
    clientContext.executeQueryAsync(onRequestSucceeded, onRequestFailed);
}
function onRequestSucceeded() {
    // Ensure that the SP.UserProfiles.js file is loaded before the custom code runs.

    websiteurl = website.get_url();
    SP.SOD.executeOrDelayUntilScriptLoaded(GetFeeds, 'SP.UserProfiles.js');
}
function onRequestFailed(sender, args) {
    alert('Error: ' + args.get_message());
}


function GetFeeds() {

    // Initialize the current client context and the SocialFeedManager instance.
    clientContext = SP.ClientContext.get_current();

    feedManager = new SP.Social.SocialFeedManager(clientContext);

    // Set parameters for the feed content that you want to retrieve.
    var feedOptions = new SP.Social.SocialFeedOptions();
    feedOptions.set_maxThreadCount(10); // default is 20
    // debugger;
    subsiteurl = $('.microblog_projectsdl option:selected').val();
    // Get all feed types for current site and get the Personal feed
    allfeeds = feedManager.getFeedFor(websiteurl + "/" + subsiteurl + "/newsfeed.aspx", feedOptions);
    clientContext.load(feedManager);
    clientContext.executeQueryAsync(CallIterateFunctionForFeeds, RequestFailed);
}
function CallIterateFunctionForFeeds() {
    IterateThroughFeed(allfeeds, "News", false);
}
function IterateThroughFeed(feed, feedType, isCurrentUser) {
    var unreadcnt = feedManager.getUnreadMentionCount().get_value();
    if (unreadcnt > 0) {
        document.getElementById("spnunreadpstcnt").innerHTML = unreadcnt;
    }
    else {

    }
    var threads = feed.get_threads();
    var divfeeds = "<div class=\"post-divfeeds\">";
    for (var i = 0; i < threads.length ; i++) {
        var thread = threads[i];
        var actors = thread.get_actors();

        if (thread.get_threadType() == 0) {


            // Get the root post's author, content, and number of replies.
            var post = thread.get_rootPost();
            var authorName = actors[post.get_authorIndex()].get_name();
            var postContent = post.get_text();
            var totalReplies = thread.get_totalReplyCount();
            var picURL = actors[post.get_authorIndex()].get_imageUri();
            var attachment = post.get_attachment();
            if (attachment != null) {
                var previewuri = attachment.get_uri();
                var attachmentname = attachment.get_name();
            }
            else {
                previewuri = null;
                attachmentname = null;
            }
            if (picURL == null || picURL == '') {
                picURL = "/_layouts/15/images/PersonPlaceholder.42x42x32.png";

            }
            divfeeds = divfeeds + "<div class=\"post-divfeed\"><img class=\"post-person\" src=\"" + picURL + "\" alt=\"" + authorName + "\"><span class=\"post-authorname\">" + authorName + "</span><div class=\"post-content\">" + postContent + "</div> ";

            if (previewuri != null && previewuri != '') {
                divfeeds = divfeeds + "<div class=\"post-Preview\"><img class=\"post-person\" src=\"" + previewuri + "\" alt=\"" + attachmentname + "\"></div> "
            }

            // If there are any replies, iterate through the array and
            // get the author and content. 
            // If a thread contains more than two replies, the server
            // returns a thread digest that contains only the two most
            // recent replies. To get all replies, call the 
            // SocialFeedManager.getFullThread method.
            if (totalReplies > 0) {
                divfeeds = divfeeds + "<div class=\"replypost-divfeed\">";
                var replies = thread.get_replies();

                for (var j = 0; j < replies.length; j++) {

                    var r_post = replies[j];
                    var r_authorName = actors[r_post.get_authorIndex()].get_name();
                    var r_postContent = r_post.get_text();
                    var r_picURL = actors[r_post.get_authorIndex()].get_imageUri();
                    var r_attachment = r_post.get_attachment();
                    if (r_attachment != null) {
                        var r_previewuri = r_attachment.get_uri();
                        var r_attachmentname = r_attachment.get_name();
                    }
                    else {
                        var r_previewuri = null;
                        var r_attachmentname = null;

                    }


                    if (picURL == null || picURL == '') {
                        picURL = "/_layouts/15/images/PersonPlaceholder.42x42x32.png";
                    }
                    divfeeds = divfeeds + "<div class=\"post-divfeed\"><img class=\"post-person\" src=\"" + r_picURL + "\" alt=\"" + r_authorName + "\"><span class=\"post-authorname\">" + r_authorName + "</span><div class=\"post-content\">" + r_postContent + "</div> ";

                    if (previewuri != null && previewuri != '') {
                        divfeeds = divfeeds + "<div class=\"post-Preview\"><img class=\"post-person\" src=\"" + r_previewuri + "\" alt=\"" + r_attachmentname + "\"></div> "
                    }
                    divfeeds = divfeeds + "</div>";
                }
                divfeeds = divfeeds + "</div>";
            }

            divfeeds = divfeeds + "</div>";
        }
        divfeeds = divfeeds + "</div>";
    }
    document.getElementById("newsfeedSection").innerHTML = divfeeds;
}
function RequestFailed(sender, args) {
    $get("spanMessage").innerText = 'Request failed: ' + args.get_message();
}


//Publish

var resultThread;

function PublishPost() {
    // Initialize the current client context and the SocialFeedManager instance.
    clientContext = SP.ClientContext.get_current();
    feedManager = new SP.Social.SocialFeedManager(clientContext);
    //var socialDataItems = [linkDataItem];
    var content = document.getElementById("txtPost").innerText;
    // Create the post content.
    var postCreationData = new SP.Social.SocialPostCreationData();
    postCreationData.set_contentText(content);
    subsiteurl = $('.microblog_projectsdl option:selected').val();
    // Publish the post. Pass null for the "targetId" parameter because this is a root post.
    resultThread = feedManager.createPost(websiteurl + "/" + subsiteurl + "/newsfeed.aspx", postCreationData);
    clientContext.executeQueryAsync(PublishReply, PostFailed);
}
function PublishReply(sender, args) {
    GetFeeds();
    document.getElementById("txtPost").innerText = '';
}

function PostFailed(sender, args) {
    alert('Error: ' + args.get_message());
}