Refactoring your Vue 2 apps to Vue 3

Vue 3 introduces significant improvements over Vue 2, primarily through the Composition API, which enhances code organization and reusability by allowing developers to structure component code based on logical concerns. This tutorial guides developers through upgrading a Vue 2 application to Vue 3, using an open-source to-do list app as an example. It covers key differences between the versions, like the use of the `createApp` method in Vue 3 instead of `new Vue()` in Vue 2, and shows how to refactor components using Vue 3 features, such as the `setup()` function, `onMounted()` hook, and `ref` for reactivity. The tutorial also details the process of upgrading dependencies and enabling compat mode to support Vue 3's new syntax while maintaining existing functionality. Additionally, it highlights how to implement new Vuex 4 features, including creating a Vuex store with the `createStore` method and updating the store to handle actions like fetching and adding to-dos. The guide aims to familiarize developers with the improved structure and capabilities of Vue 3, encouraging them to explore further by refactoring additional CRUD operations and utilizing the GitHub repository for reference.