methods方法绑定this
问题一：不能使用箭头函数？
https://mp.weixin.qq.com/s/hYm0JgBI25grNG_2sCRlTA；
问题二：this到底指向什么？
事实上Vue的源码当中就是对methods中的所有函数进行了遍历，并且通过bind绑定了this：
VSCode代码片段
https://snippet-generator.app/
代码片段过程
模板语法
Mustache双大括号语法
01_Mustache语法.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<div id="app"></div>
<template id="my-app">
<!-- 1.mustache的基本使用 -->
<h2>{{message}} - {{message}}</h2>
<!-- 2.是一个表达式 -->
<h2>{{counter * 10}}</h2>
<h2>{{ message.split(" ").reverse().join(" ") }}</h2>
<!-- 3.也可以调用函数 -->
<!-- 可以使用computed(计算属性) -->
<h2>{{getReverseMessage()}}</h2>
<!-- 4.三元运算符 -->
<h2>{{ isShow ? "哈哈哈": "" }}</h2>
<button @click="toggle">切换</button>
<!-- 错误用法 -->
<!-- var name = "abc" -> 赋值语句 -->
<!-- <h2>{{var name = "abc"}}</h2>
<h2>{{ if(isShow) { return "哈哈哈" } }}</h2> -->
</template>
<script src="../js/vue.js"></script>
<script>
const App = {
template: '#my-app',
data() {
return {
message: "Hello World",
counter: 100,
isShow: true
}
},
methods: {
getReverseMessage() {
return this.message.split(" ").reverse().join(" ");
},
toggle() {
this.isShow = !this.isShow;
}
}
}
Vue.createApp(App).mount('#app');
</script>
</body>
</html>
v-once指令
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<div id="app"></div>
<template id="my-app">
<h2>{{counter}}</h2>
<div v-once>
<h2>{{counter}}</h2>
<h2>{{message}}</h2>
</div>
<button @click="increment">+1</button>
</template>
<script src="../js/vue.js"></script>
<script>
const App = {
template: '#my-app',
data() {
return {
counter: 100,
message: "abc"
}
},
methods: {
increment() {
this.counter++;
}
}
}
Vue.createApp(App).mount('#app');
</script>
</body>
</html>
v-text指令
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<div id="app"></div>
<template id="my-app">
<h2 v-text="message"></h2>
<h2>{{message}}</h2>
</template>
<script src="../js/vue.js"></script>
<script>
const App = {
template: '#my-app',
data() {
return {
message: "Hello World"
}
}
}
Vue.createApp(App).mount('#app');
</script>
</body>
</html>
v-html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<div id="app"></div>
<template id="my-app">
<div>{{msg}}</div>
<div v-html="msg"></div>
</template>
<script src="../js/vue.js"></script>
<script>
const App = {
template: '#my-app',
data() {
return {
msg: '<span style="color:red; background: blue;">哈哈哈</span>'
}
}
}
Vue.createApp(App).mount('#app');
</script>
</body>
</html>
v-pre
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<div id="app"></div>
<template id="my-app">
<h2 v-pre>{{message}}</h2>
</template>
<script src="../js/vue.js"></script>
<script>
const App = {
template: '#my-app',
data() {
return {
message: "Hello World"
}
}
}
Vue.createApp(App).mount('#app');
</script>
</body>
</html>
v-cloak
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
[v-cloak] {
display: none;
}
</style>
</head>
<body>
<div id="app"></div>
<template id="my-app">
<h2 v-cloak>{{message}}</h2>
</template>
<script src="../js/vue.js"></script>
<script>
const App = {
template: '#my-app',
data() {
return {
message: "Hello World"
}
}
}
Vue.createApp(App).mount('#app');
</script>
</body>
</html>