Browser memory leak detection

Summary

Heap snapshot diff — detached DOM, growing listeners, closures holding large graphs. Performance monitor JS heap trend over SPA navigations. Common: charts, maps, global caches without eviction. Fix teardown in useEffect return and route leave.

Code example

const baseline = performance.memory?.usedJSHeapSize;

function checkLeak() {
  const current = performance.memory?.usedJSHeapSize;
  if (baseline && current - baseline > 5_000_000) {
    console.warn('Heap grew by', current - baseline, 'bytes');
  }
}

Key points

• Heap snapshot diff — detached DOM, growing listeners, closures holding large graphs.
• Performance monitor JS heap trend over SPA navigations.
• Common: charts, maps, global caches without eviction.
• Fix teardown in useEffect return and route leave.

Further reading

• Memory management
• performance.memory

Related concepts

• Long Tasks API
• Accessibility tree