How does Vue.js's reactivity system interact with promises and async/await?

Vue.js's reactivity system automatically updates the DOM when data changes. When using `async/await` to fetch data, Vue's reactivity system will trigger a re-render when the data is available. This means that the component will update its view automatically when the promise resolves. If the promise rejects, you can use Vue's `error` event to handle the error and display an error message. Consider using computed properties or watchers to manage the data fetched from promises in a reactive manner.