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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.

HTML

              
                <h1>CSS Flex: Smooth Wrapping</h1>
<div class="title">(no dependency libraries)</div>
<div class="title-link"><a href="https://codepen.io/KeithDC/post/css-flex-smooth-wrapping-success-no-dep-libs">CodePen Post (the backstory)</a></div>

<div class="wrapper">
  <div class="options">
    <button class="button">Change Width</button>
    <p>Although the 'Change Width' button works, the transitons are cleaner when resizing the window/frame.</p>
  </div>

  <div class="container">
    <div class="item item-node">1</div>
    <div class="item item-node">2</div>
    <div class="item item-node">3</div>
    <div class="item item-node">4</div>
    <div class="item item-node">5</div>
    <div class="item item-node">6</div>
  </div>
</div>
              
            
!

CSS

              
                body {
  margin: 0 auto;
}
.wrapper {
  margin: 1rem auto;
  padding: 0 0 1rem;
  position: relative;
  text-align: center;
  width: 95%;
}
.container {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  justify-content: space-around;
  margin: 0 auto;
  padding: 0 0.5rem 1rem;
  position: relative;
  transition: all 2s;
}
.container > div.item {
  align-items: center;
  background-color: hsl(133, 100%, 80%);
  display: flex;
  flex: 0 1 auto;
  justify-content: center;
  outline: 3px solid green;
  margin: 0.5rem;
  padding: 0.5rem;
  position: relative;
    min-height: 100px;
    width: 150px;
  transition: top 0.5s, left 0.5s;
}
.container > div.item-node {
  visibility: hidden;
}
.container > div.item-dupe {
  position: absolute;
  visibility: visible;
}

/*  Superfluous  */

h1,
h2,
h3 {
  color: green;
  margin: 1rem auto 0;
  padding: 0;
  text-align: center;
}
.title,
.title-link {
  color: green;
  margin: 0.75rem auto 0;
  text-align: center;
}
.title-link {
  margin: 0.5rem auto 0;
}
.title-link a {
  color: orange;
  text-decoration: none;
  transition: all 0.25s;
}
.title-link a:hover {
  color: maroon;
  text-decoration: none;
  transition: all 0.25s;
}
.container.switch {
  transition: all 2s;
  width: 50%;
}
div.options {
  margin: 0 auto;
  padding: 1rem 0 0;
  text-align: center;
  width: 400px;
}
  button {
    cursor: pointer;
  }
  div.options p {
    opacity: 0.5;
  }
.no-bold {
  font-weight: normal;
}
              
            
!

JS

              
                const nodes = document.querySelectorAll(".item-node"),
      totalNodes = nodes.length,
      boxes = [];

let nodeCnt = 0,      // Node count: Loop through nodes[]
    resizeWaitID = 0, // setTimeout ID for window.resize()
    node = {},
    dupe = {};

for (nodeCnt = 0; nodeCnt < totalNodes; nodeCnt++) {
  node = nodes[nodeCnt];

  dupe = node.cloneNode(true);        // We'll clone each node so it can "follow" its sibling `node` element around the UI.
  dupe.classList.remove("item-node"); // .item-node | visibility: hidden - Will move natively with Flex wrapping (snappy!).
  dupe.classList.add("item-dupe");    // .item-dupe | visibility: visible - Will smoothly follow sibling .item-node around.

  node.parentNode.appendChild(dupe);  // Position: `absolute` - Each clone stays relative to their shared parent container.

  dupe.style.top = node.offsetTop + 'px';   // Establish each dupe's `absolute` position.
  dupe.style.left = node.offsetLeft + 'px'; // <--^

  boxes[nodeCnt] = { node, dupe };
}

function moveNodes() {
  clearTimeout(resizeWaitID);
  resizeWaitID = setTimeout(() => {
    for (nodeCnt = 0; nodeCnt < totalNodes; nodeCnt++) {
      boxes[nodeCnt].dupe.style.left = boxes[nodeCnt].node.offsetLeft + 'px';
      boxes[nodeCnt].dupe.style.top = boxes[nodeCnt].node.offsetTop + 'px';
    }
  }, 101);
}

window.addEventListener("resize", moveNodes);

const divSwitch = document.querySelector('.container');

document.querySelector('.button').addEventListener('click', e => {
  moveNodes();
  divSwitch.classList.toggle('switch');
});

              
            
!
999px

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