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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.


              <div id="node">
  <div class="content"
    Lorem Ipsum Dolor Sit Amet




  width: 140,
  height: 50

var resizer = (() => {
  // we save observers so they don't get garbage collected
  var resizers = [];
  return (node, callback) => {
    if (window.ResizeObserver) {
      var resizer = new ResizeObserver((entries) => {
        var rect = entries[0].contentRect;
      return () => {
        resizers = resizers.filter(r => r != resizer);
    } else {
      return () => undefined;

// ES Next Observable code taken from proposal repo and run through babel
// (+ removed exports)
var resizeObserable = new Observable(observe => {
  //resizeObserver supported only by Google Chrome behind the flag
  if (window.ResizeObserver) {
    return resizer(document.querySelector("#node div"), (entry) => {{
        width: entry.contentRect.width,
        height: entry.contentRect.height
  } else {
    return () => undefined;
  next({width, height, target}) {
    target.dispatchEvent(new CustomEvent('resize', {detail: {width,height}}));
    console.log(width + 'x' + height);
document.querySelector('.content').addEventListener('resize', (e) => {

var mutations = new MutationObserver(function(mutations) {
   console.log('coś zmodyfikowało element');
var node = document.querySelector('#node');
mutations.observe(node, {
   childList: true,
   subtree: true,
   attributes: true

// aby wyłączyć obsweratora
// observer.disconnect();
// obserwator wywoła się gdy np. wywołamy
node.setAttribute('data-foo', 'bar');