rxjs - Example of Pull vs Push

rxjs-pull-vs-push.js

//Traditional imperative pull based
window.setInterval(() => {
  const tweets = getNewTweets();
  for(let tweet of tweets){
    if(!tweet.message.contains("Greetings!")) continue;
    
    getUserAvatar(tweet.user)
     .then(avatar => {
      const $avatar  = $(`<img />`);
      $avatar.attr('src', avatar.url);
      $avatars.append($avatar);
    });
  }
}, 5000);

// Reactive push based 
observeTweets()
 .filter(s => s.message.contains('Greetings!'))
 .flatMap(s => getUserAvatar(s.user))
 .map( a => $('< img/>').attr('src', a.url))
 .subscribe($avatar => {
  $avatars.append($avatar);
 });