Run code at specific moments.
✍️ 3 exercises + code challenge in this lessonLifecycle hooks run at key moments in a component's life:
created: data is ready, but nothing is on the page yet.mounted: the component is on the page. Fetch data or access the DOM here.updated: after a re-render.unmounted: clean up timers and listeners.Mastering Vue Lifecycle Hooks helps you write clean and reliable Vue.js code. Follow standard conventions, test edge cases, and keep logic simple. Try running the code example below and complete the exercises to build confidence.
<script src="https://unpkg.com/vue@3.5.12/dist/vue.global.prod.js"></script>
<div id="app">
<h2>{{ time }}</h2>
<ul><li v-for="u in users" :key="u.id">{{ u.name }}</li></ul>
</div>
<script>
Vue.createApp({
data() { return { time: "", users: [] }; },
async mounted() {
this.timer = setInterval(() => this.time = new Date().toLocaleTimeString(), 1000);
const res = await fetch("https://jsonplaceholder.typicode.com/users?_limit=3");
this.users = await res.json();
},
unmounted() { clearInterval(this.timer); }
}).mount("#app");
</script>Check what you learned in “Vue Lifecycle Hooks”.
Run code after the component is on the page.
() { this.load(); }
Where should you clear timers?
In the mounted hook, set status to "Ready".
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