Why Not Redux?
When building the ISO Checklist XP application, the primary requirement was persistent state tracking across 200+ checkboxes. The immediate instinct of a modern web developer is to reach for Redux Toolkit or Zustand. However, the overhead of React and an external state library for what is essentially a highly stylized form felt architecturally heavy.
The Proxy Pattern
We opted to build a custom reactive store utilizing JavaScript ES6 Proxies. A Proxy allows developers to intercept and redefine fundamental operations for an object, such as getting, setting, and defining properties.
By wrapping our plain JavaScript state object in a Proxy, we created a custom set() trap. Every time a checkbox value changes, the trap intercepts the assignment, automatically writes the serialized state to localStorage, and triggers a pub-sub event to re-render the specific DOM nodes that display the overall completion percentage.
Zero Dependency Architecture
This zero-dependency approach resulted in a total JavaScript payload of under 8KB. It boots instantly, is completely impervious to dependency-chain vulnerabilities, and is trivial to debug. It serves as a stark reminder that modern Vanilla JS often has the tools we need built right into the spec.