Some friends feel that Vue updates too quickly, causing the knowledge taught in the course to be inconsistent with the current Vue version, thus reporting errors. This article mainly shares with you a summary of the changes in Vue.js2.0, hoping to help everyone.
1. Regarding $index in Vue, getting the index value has been cancelled. It is mostly used for operations on multiple elements, like li in ul. Multiple li's are created through v-for. If for one of them or For some li operations, you need to use the index value. The usage is as follows;
<template> <p class="hello"> <h1 id="nbsp-msg-nbsp">{{ msg }}</h1> <button v-on:click="reverse">点击</button> <input v-model="newtodo" v-on:keyup.enter="add"> <ul> <li v-for="(todo,index) in todos"> <span>{{todo.text}}</span> <button v-on:click="remove(index)">删除</button> </li> </ul> </p> </template> <script> export default { name: 'HelloWorld', data () { return { msg: 'Welcome to Your Vue.js App', todos: [ {text:'我是一开始就有的哦!'} ], newtodo: '' } }, methods: { reverse: function(){ this.msg = this.msg.split('').reverse().join('') }, add: function(){ var text = this.newtodo.trim(); if(text){ this.todos.push({text:text}); this.newtodo = '' } }, remove: function(index){ this.todos.splice(index,1) } } } </script>
This is a fragment I built myself, focusing on the use of index.
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The above is the detailed content of Vue.js2.0 changes summary sharing. For more information, please follow other related articles on the PHP Chinese website!

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Understanding how JavaScript engine works internally is important to developers because it helps write more efficient code and understand performance bottlenecks and optimization strategies. 1) The engine's workflow includes three stages: parsing, compiling and execution; 2) During the execution process, the engine will perform dynamic optimization, such as inline cache and hidden classes; 3) Best practices include avoiding global variables, optimizing loops, using const and lets, and avoiding excessive use of closures.


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