Detached DOM nodes

Summary

Nodes removed from document but referenced in JS prevent GC — classic memory leak in SPAs (closures holding elements, forgotten listeners). WeakMap patterns or explicit cleanup in effects. DevTools Memory heap snapshot → Detached nodes count. Common in chart libraries, modals, infinite scroll without teardown.

Code example

const cache = new WeakMap();

function mountWidget(container) {
  const widget = createWidget(container);
  cache.set(container, widget);
  return () => {
    widget.destroy();
    cache.delete(container);
  };
}

Key points

• Nodes removed from document but referenced in JS prevent GC — classic memory leak in SPAs (closures holding elements, forgotten listeners).
• WeakMap patterns or explicit cleanup in effects.
• DevTools Memory heap snapshot → Detached nodes count.
• Common in chart libraries, modals, infinite scroll without teardown.

Further reading

• Memory management
• WeakMap

Related concepts

• Subpixel rendering
• Garbage collection timing