how-to-connect-discourse-to-slack

function.js

var result = {
  newPost: null,
  newPostId: null
};

// If this is the first time through, lastID will be undefined.
// Set it to the most recent post and return.
if(!payload.data.lastId) {
  if(payload.data.latest.body.latest_posts.length) {
    result.newPostId = payload.data.latest.body.latest_posts[0].id;
    return result;
  }
}

result.newPostId = Number.MAX_VALUE;

// Find the oldest post that is still newer than lastId.
payload.data.latest.body.latest_posts.forEach(function(post) {
  if(post.id > payload.data.lastId) {
    if(post.id < result.newPostId) {
      result.newPost = post;
      result.newPostId = post.id;
    }
  }
});

// If it didn't find one newer, set it back to lastId.
result.newPostId = result.newPost ? result.newPost.id : payload.data.lastId;

return result;