Vue中使用方法、计算属性或观察者的方法实例详解

<div id="app">
 <input v-model="firstName" type="text">
 <input v-model="secondName" type="text">
 <p>{{fullName}}</p>
</div>

var vm = new Vue({
 el: "#app",
 data: {
 firstName: "Mo",
 secondName: "deng",
 fullName: ""
 },
 methods: {
 getFullName () {
  this.fullName = this.firstName + "" + this.secondName;
 }
 },
 mounted () {
 this.getFullName();
 }
});

var vm = new Vue({
 el: "#app",
 data: {
 firstName: "liu",
 secondName: "deng"
 },
 computed: {
 fullName () {
  return this.firstName + "" + this.secondName;
 }
 }
});

var vm = new Vue({
 el: "#app",
 data: {
 firstName: "liu",
 secondName: "deng",
 fullName: "liudeng"
 },
 watch: {
 firstName: function (value) {
  this.fullName = value+ "" + this.secondName
 },
 secondName: function (value) {
  this.fullName = this.firstName + "" + value
 }
 }
});

<button class="todo-remove" type="button" @click="removeTodoItem(item)">x</button>

export default {
 name: "TodoList",
 data() {
 return {
  todoType: "all", //任务类型
  allTodoItems: [],
 };
 },
 methods: {
 //... 省略

 //添加任务
 addItem() {
  this.allTodoItems.push({
  id: this.allTodoItems.length,
  text: this.itemText,
  completed: false
  });
  this.itemText = "";
 },
 //删除任务
 removeTodoItem(item) {
  this.allTodoItems = this.allTodoItems.filter(
  value => value.id != item.id
  );
 }
 }
};

export default {
 name: "TodoList",
 data() {
 return {
  todoType: "all", //任务类型
  allTodoItems: [],
 };
 },
 computed: {
 //展示的任务
 passTodoItems() {
  return this[this.todoType](this.allTodoItems);
 },
 //是否显示底部的选项
 isShowOptions() {
  return this.allTodoItems.length;
 }
 }
}

export default {
 name: "TodoList",
 data() {
 return {
  todoType: "all", //任务类型
  allTodoItems: [],
 };
 },
 watch: {
 allTodoItems: {
  handler() {
  localStorage.setItem("todoItems", JSON.stringify(this.allTodoItems));
  },
  deep: true //深度监听对象属性的变化，如果没有检测不到对象属性的变化
 }
 }
}