Explain Reactive Data in Vue.js

Vue.js achieves reactivity through a combination of its reactivity system and the Virtual DOM. When a Vue instance is created, Vue.js recursively walks through all the properties of the data objects passed into the instance and converts them into getters and setters using Object.defineProperty. This process is often referred to as reactive data transformation. These getters and setters are invisible to the developer but allow Vue to track when a property is read or modified.

Every component instance has a corresponding watcher instance, which records any properties "touched" during the component's render as dependencies. Later, when a...