Framework7 Architecture and Lifecycle Considerations

Virtual DOM vs DOM Injection

Framework7 supports both traditional page loading (via router.navigate) and component-based virtual DOM with dynamic routing. However, in hybrid apps using custom events or third-party plugins, developers frequently mix static HTML, JavaScript-injected pages, and component routing, which results in memory bloat or duplicate event bindings.

Page and View Lifecycle

Each Framework7 page follows a defined lifecycle: pageInit, pageBeforeIn, pageAfterIn, and pageBeforeRemove. Failing to clean up resources in pageBeforeRemove (e.g., custom timers, event listeners, media instances) can leave memory and DOM artifacts that accumulate over time.

Symptoms and Diagnostic Clues

Identifying the Problem

• App slows down after multiple view navigations
• Media players or modals persist after view change
• DevTools timeline shows increasing JS heap
• Event handlers fire multiple times

Memory Snapshot Analysis

Use Chrome DevTools or Safari's Web Inspector to capture memory snapshots. Look for detached DOM nodes, retained closures, or zombie components. Pay attention to objects linked to page-content or f7-page classes.

// Inspect retained listeners
window._listeners = getEventListeners(document.querySelector('.f7-page'));
console.log(window._listeners);

Root Causes and Pitfalls

1. Improper Cleanup in pageBeforeRemove

Framework7 does not auto-remove all resources. If timers, intervals, media, or event listeners are set up during pageInit, they must be explicitly cleaned.

// Inside pageBeforeRemove callback
on: {
  pageBeforeRemove() {
    clearInterval(this.myTimer);
    videoEl.pause();
    videoEl.src = '';
    videoEl.load();
    app.off('custom-event', handler);
  }
}

2. Event Handler Duplication Across Views

Registering global events like app.on('custom-event') in multiple pages without unbinding them leads to duplicated logic and memory leaks.

3. Cached Pages Holding DOM References

By default, Framework7 caches pages. This means DOM and JS context are preserved unless explicitly disabled. For memory-sensitive apps, consider disabling page caching for dynamic views.

{
  path: '/page/',
  componentUrl: './pages/memory-heavy.html',
  options: {
    reloadCurrent: true,
    ignoreCache: true
  }
}

Step-by-Step Remediation

1. Properly Use Lifecycle Hooks

Always attach heavy resource cleanup in pageBeforeRemove and initialization logic in pageInit.

2. Disable Page Caching Selectively

For memory-intensive or third-party dependent views, disable caching in router definitions using ignoreCache: true.

3. Use app.off() for Event Unbinding

Always keep a reference to event handlers so they can be cleanly removed on view teardown.

4. Manage DOM References Explicitly

Ensure any dynamically created DOM elements are manually detached or nulled in pageBeforeRemove.

Best Practices for Enterprise Applications

• Encapsulate all page-specific logic inside the page lifecycle handlers
• Monitor and audit retained DOM via memory snapshots regularly
• Avoid using global state unless managed via a store like Store7 or Vuex
• Use router hooks to trigger cleanup logic outside component scope when needed
• Test on both iOS and Android, as memory behavior differs between platforms

Conclusion

Framework7 remains a top-tier choice for building native-like hybrid apps, but its flexibility also opens the door for subtle memory leaks and lifecycle mismatches. Proper management of dynamic views, event bindings, and page lifecycle is vital for long-term app performance. With disciplined use of hooks like pageBeforeRemove and conscious memory management, enterprise developers can harness Framework7's power without compromising reliability or performance.

FAQs

1. Why is my Framework7 app slow after navigating multiple views?

It's likely due to retained DOM elements or duplicate event listeners not cleaned during page transitions. Use memory tools to verify and cleanup in pageBeforeRemove.

2. How do I detect if event handlers are duplicated?

Use browser DevTools' getEventListeners() or set custom logging flags on event bindings to detect multiple firings.

3. Should I always disable page caching?

No, only disable it for pages that load heavy resources, media, or third-party plugins. For static content, caching improves performance.

4. Can I use Vue components inside Framework7?

Yes, Framework7-Vue allows Vue-based routing and component use. However, be extra cautious about Vue's lifecycle coexisting with Framework7's page lifecycle.

5. What's the best way to manage global events?

Centralize global event registration in a service or store, and ensure proper unbinding when the event's lifecycle ends or the page is removed.