<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Vue的方法_侠课岛(9xkd.com)</title>
<script src="https://unpkg.com/vue@next"></script>
</head>
<body>
<div id="computed-basics">
<p>Has published books:</p>
<span>{{ publishedBooksMessage }}</span>
</div>
<script>
Vue.createApp({
data() {
return {
author: {
name: 'John Doe',
books: [
'Vue 2 - Advanced Guide',
'Vue 3 - Basic Guide',
'Vue 4 - The Mystery'
]
}
}
},
computed: {
// 计算属性的 getter
publishedBooksMessage() {
// `this` 指向 vm 实例
return this.author.books.length > 0 ? 'Yes' : 'No'
}
}
}).mount('#computed-basics')
</script>
<style>
.demo {
font-family: sans-serif;
border: 1px solid #eee;
border-radius: 2px;
padding: 20px 30px;
margin-top: 1em;
margin-bottom: 40px;
user-select: none;
overflow-x: auto;
}
</style>
</body>
</html>
methods：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Vue的方法_侠课岛(9xkd.com)</title>
<script src="https://unpkg.com/vue@next"></script>
</head>
<body>
<div id="computed-basics">
<p>Has published books:</p>
<p>{{ calculateBooksMessage() }}</p>
</div>
<script>
Vue.createApp({
data() {
return {
author: {
name: 'John Doe',
books: [
'Vue 2 - Advanced Guide',
'Vue 3 - Basic Guide',
'Vue 4 - The Mystery'
]
}
}
},
// 在组件中
methods: {
calculateBooksMessage() {
return this.author.books.length > 0 ? 'Yes' : 'No'
}
}
}).mount('#computed-basics')
</script>
<style>
.demo {
font-family: sans-serif;
border: 1px solid #eee;
border-radius: 2px;
padding: 20px 30px;
margin-top: 1em;
margin-bottom: 40px;
user-select: none;
overflow-x: auto;
}
</style>
</body>
</html>
是否需要有缓存的关系，methods，不希望有缓存。
没有缓存，就一直更新？
有缓存，就不更新？
