Show HN: Flynt.js – 2.2kb, zero-build, CSP-safe reactivity library for MPAs

Hi HN! Creator of Flynt.js here.

I built Flynt.js to solve a common pain point in Multi-Page Application (MPA) setups like Magento/Hyvä, Laravel, and Rails: managing complex UI state without polluting HTML templates with heavy inline JS logic or dragging in massive framework bundles.

Key features: - Zero-build & Lightweight: ~150 lines of plain JS, zero dependencies. - Clean HTML (Presenter Pattern): Decouples logic into JS Presenters instead of heavy inline template attributes. - 100% Strict CSP Compliant: Never uses eval() or new Function(). - Native-friendly: Built-in automatic request aborting (no race conditions) and key-based DOM diffing for lists.

Currently working on a form extension for native HTML5 validation handling.

Would love to hear your feedback, thoughts, or suggestions!

https://github.com/marsbos/flynt.js