Composition API vs. Options API for Incremental Vue 3 Migration

Migration Strategy for Vue 2 to Vue 3

When migrating a small application to Vue 3, the primary goal is to maintain stability while updating the reactivity system from Object.defineProperty to Proxy-based tracking. A common approach involves choosing between a full conversion to the Composition API or retaining the Options API for existing components.

Constraints and Trade-offs

The Options API allows for a faster, lower-risk migration by minimizing breaking changes in component structure. However, the Composition API provides better logic reuse and type inference, which are critical for long-term maintainability. Mixing both patterns within a single application is supported, but it introduces inconsistency in how state is managed and how reactivity is tracked across the component tree.

There is uncertainty regarding the impact of this hybrid approach on state synchronization and the potential for over-reactivity when using reactive() alongside traditional data properties.

• Does maintaining a hybrid API structure significantly complicate the debugging of reactivity graphs in Vue Devtools?
• Which approach better preserves component state during Hot Module Replacement (HMR) when migrating incrementally?