Vuex

Vuex is a centralized state management pattern and library for Vue.js applications. It stores all the components in an application following rules that ensure the state is only mutated in a predictable manner. Unlike other management patterns, Vuex defines and separates the concepts involved in state management, and enforces rules that maintain independence between views and states. It is also a library implementation that's specifically tailored for Vue.js, so as to take advantage of its granular reactivity system for efficient updates.

Vuex is ideal for building a medium-to-large-scale SPA, as it is better at handling state outside of Vue components.