deleteItem

(function(){
	'use strict';

	// two way data binding
	var vm = new Vue({
		el: '#app',
		data: {
			newItem: '',
			todos: [
				'task 1',
				'task 2',
				'task 3'
			]
		},
		methods: {
			addItem: function(e){
				e.preventDefault();
				this.todos.push(this.newItem);
				this.newItem = '';
			},
			deleteItem: function(index){
				if (confirm('are you sure?')){
					this.todos.splice(index, 1);
				}
			}
		}
	});
})();
<body>
	<div id="app" class="container">
		<h1>My Todo</h1>
		<ul>
			<li v-for="(todo, index) in todos">
			{{ todo }}
			<span @click="deleteItem(index)">[x]</span>
			</li>
		</ul>
	
	<form @submit="addItem">
		<input type="text" v-model="newItem">
		<input type="submit" value="Add">
	</form>
	</div>
	<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
	<script src="js/main.js"></script>
</body>