demo/lazy_load.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Lazy loading demo</title>

  <link rel="stylesheet" href="demo.css"/>
  <script src="../dist/gridstack-all.js"></script>
</head>
<body>
  <div>
    <h1>Lazy loading + renderCB demo</h1>
    <p>New V11 GridStackWidget.lazyLoad feature. open console and see widget content (or angular components) created as they become visible.</p>
    <div style="height: 300px; overflow-y: auto">
      <div class="grid-stack"></div>
    </div>
  </div>
  <script type="text/javascript">
    // print when widgets are created, verify dragging by newly added content
    GridStack.renderCB = function(el, w) {
      const title = document.createElement('h3');
      title.textContent = 'Drag me by title';
      title.className = 'card-header';
      el.appendChild(title);
      const div = document.createElement('div');
      div.textContent = w.id;
      el.appendChild(div);
      console.log('created node id ', w.id);
    };

    let children = [];
    for (let y = 0; y <= 5; y++) children.push({x:0, y, id:String(y), content: String(y)});
    
    let grid = GridStack.init({
      cellHeight: 200,
      children,
      lazyLoad: true,  // delay creation until visible
      handle: '.card-header',
    });
  </script>
</body>
</html>