Using methods on your Vue instance to get formatted data is great, but it comes with the heavy toll of running every time the view is updated or re-rendered. We can avoid paying this performance toll by using computed properties. Sometimes we also need to be able to perform background, or asynchronous, tasks when the user interacts with the page, but we don’t want to block the user from interacting. Vue provides us the option of using watches in these cases.
In this chapter, we will learn about computer properties and watchers and how to use them in Vue.