hide /Star Wars/-related posts on Facebook

hideStarWars.user.js

// ==UserScript==
// @match https://www.facebook.com/*
// ==/UserScript==

// My very first user script!
// @see https://www.chromium.org/developers/design-documents/user-scripts
// @see http://wiki.greasespot.net/Metadata_Block
// Note that match patterns require a path component.  I ran into trouble earlier by leaving off the trailing slash.
// @see https://developer.chrome.com/extensions/match_patterns

var searches = [
  'Star Wars',
  'The Force Awakens',
  'Episode VII'
  // et c.
].map(function(search) { return new RegExp(search, 'i') });

// 'There is no way to stop or break a forEach() loop other than by throwing an exception. . . . If you are testing the array elements for a predicate and need a [B]oolean return value, you can use every() or some() instead.'
// @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach#Description
function isStarWarsRelated(postText) {
  return searches.some(function(search) {
    return ( postText.match(search) !== null );
  });
}

function getStoryNode(contentNode) {
  var node = contentNode;

  while(node) {
    var attribute = node.attributes.getNamedItem('data-ft') || null;

    if( (attribute !== null) && ( Object.keys( JSON.parse(attribute.value) ).indexOf('fbfeed_location') !== -1 ) ) {
      break;
    } else {
      node = node.parentNode;
    }
  }

  return (node.tagName !== 'HTML')
    ? node
    : null;
}

function filterPosts() {
  // @see https://coderwall.com/p/jcmzxw/iterate-over-queryselectorall-result
  [].forEach.call(
    document.querySelectorAll('.userContentWrapper'),
    function(post) {
      if( isStarWarsRelated(post.textContent) ) {
        var storyNode = getStoryNode(post);

        // Note that this merely hides posts; it doesn't remove them from the DOM.
        if(storyNode !== null) { storyNode.style.display = 'none' }
      }
    }
  );
}

// Filter initially, on page load.
document.addEventListener('DOMContentLoaded', filterPosts);

// @see https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver
var observer = new MutationObserver(function(mutations) {
  // Filter whenever Facebook loads new content asynchronously.
  mutations.forEach(function(mutation) { filterPosts() })
});

observer.observe(document, {
  childList: true,
  subtree: true
});

Well, it only took 14 revisions, but it's much prettier now --- and it targets all content blocks, not just those on the News Feed.