响应式
声明状态
更新状态
计算属性
<script setup>
import { ref, computed } from "vue";
const count = ref(10);
const doubleCount = computed(() => count.value * 2);
</script>
<template>
<div>{{ doubleCount }}</div>
</template>
模板语法
样式
DOM循环
点击事件
<script setup>
import { ref } from "vue";
const count = ref(0);
function incrementCount() {
count.value++;
}
</script>
<template>
<p>计数器: {{ count }}</p>
<button @click="incrementCount">+1</button>
</template>
DOM引用
条件渲染
<script setup>
import { ref, computed } from "vue";
const TRAFFIC_LIGHTS = ["红灯", "黄灯", "绿灯"];
const lightIndex = ref(0);
const light = computed(() => TRAFFIC_LIGHTS[lightIndex.value]);
function nextLight() {
lightIndex.value = (lightIndex.value + 1) % TRAFFIC_LIGHTS.length;
}
</script>
<template>
<button @click="nextLight">下一个灯</button>
<p>现在亮着的是: {{ light }}</p>
<p>
你应该
<span v-if="light === '红灯'">停下</span>
<span v-else-if="light === '黄灯'">慢行</span>
<span v-else-if="light === '绿灯'">赶紧走</span>
</p>
</template>
<div
x-data="{
TRAFFIC_LIGHTS: ['红灯', '黄灯', '绿灯'],
lightIndex: 0,
get light() { return this.TRAFFIC_LIGHTS[this.lightIndex] },
nextLight() {
this.lightIndex = (this.lightIndex + 1) % this.TRAFFIC_LIGHTS.length;
}
}"
>
<button x-on:click="nextLight">下一个灯</button>
<p>现在亮着的是: <span x-text="light"></span></p>
<p>
你应该
<span x-show="light === '红灯'">停下</span>
<span x-show="light === '黄灯'">慢行</span>
<span x-show="light === '绿灯'">赶紧走</span>
</p>
</div>
生命周期
组件加载时
<script setup>
import { ref, onMounted } from "vue";
const pageTitle = ref("");
onMounted(() => {
pageTitle.value = document.title;
});
</script>
<template>
<p>页面标题: {{ pageTitle }}</p>
</template>
组件卸载时
<script setup>
import { ref, onUnmounted } from "vue";
const time = ref(new Date().toLocaleTimeString());
const timer = setInterval(() => {
time.value = new Date().toLocaleTimeString();
}, 1000);
onUnmounted(() => {
clearInterval(timer);
});
</script>
<template>
<p>当前时间: {{ time }}</p>
</template>
组件组合
组件Props传参
<script setup>
import UserProfile from "./UserProfile.vue";
</script>
<template>
<UserProfile
name="张三"
:age="20"
:favourite-colors="['green', 'blue', 'red']"
is-available
/>
</template>
<!--Alpine JS suggests using a server-side templating engine or another frontend framework in conjunction with Alpine to do this-->
<div
x-data="{
name: '张三',
age: 20,
favouriteColors: ['green', 'blue', 'red'],
isAvailable: true
}"
>
<p>我的名字是 <span x-text="张三"></span></p>
<p>My age is <span x-text="age"></span></p>
<p>
My favourite colors are <span x-text="favouriteColors.join(', ')"></span>
</p>
<p>I am <span x-text="isAvailable ? 'available' : 'not available'"></span></p>
</div>
向父组件emit事件
<script setup>
import { ref } from "vue";
import AnswerButton from "./AnswerButton.vue";
let isHappy = ref(true);
function onAnswerNo() {
isHappy.value = false;
}
function onAnswerYes() {
isHappy.value = true;
}
</script>
<template>
<p>你快乐吗?</p>
<AnswerButton @yes="onAnswerYes" @no="onAnswerNo" />
<p style="font-size: 50px">
{{ isHappy ? "😀" : "😥" }}
</p>
</template>
slot插槽
<script setup>
import FunnyButton from "./FunnyButton.vue";
</script>
<template>
<FunnyButton> 点我! </FunnyButton>
</template>
<!--Alpine JS suggests using a server-side templating engine or another frontend framework in conjunction with Alpine to do this-->
<button
x-data
x-text="'点我!'"
style="
background: rgba(0, 0, 0, 0.4);
color: #fff;
padding: 10px 20px;
font-size: 30px;
border: 2px solid #fff;
margin: 8px;
transform: scale(0.9);
box-shadow: 4px 4px rgba(0, 0, 0, 0.4);
transition: transform 0.2s cubic-bezier(0.34, 1.65, 0.88, 0.925) 0s;
outline: 0;
"
>
<span>默认slot内容</span>
</button>
slot插槽内容
<script setup>
import FunnyButton from "./FunnyButton.vue";
</script>
<template>
<FunnyButton />
<FunnyButton> 这是传到slot的内容! </FunnyButton>
</template>
<!--Alpine JS suggests using a server-side templating engine or another frontend framework in conjunction with Alpine to do this-->
<button
x-data
style="
background: rgba(0, 0, 0, 0.4);
color: #fff;
padding: 10px 20px;
font-size: 30px;
border: 2px solid #fff;
margin: 8px;
transform: scale(0.9);
box-shadow: 4px 4px rgba(0, 0, 0, 0.4);
transition: transform 0.2s cubic-bezier(0.34, 1.65, 0.88, 0.925) 0s;
outline: 0;
"
>
<span>默认slot内容</span>
</button>
<button
x-data
x-text="'这是传到slot的内容!'"
style="
background: rgba(0, 0, 0, 0.4);
color: #fff;
padding: 10px 20px;
font-size: 30px;
border: 2px solid #fff;
margin: 8px;
transform: scale(0.9);
box-shadow: 4px 4px rgba(0, 0, 0, 0.4);
transition: transform 0.2s cubic-bezier(0.34, 1.65, 0.88, 0.925) 0s;
outline: 0;
"
>
<span>默认slot内容</span>
</button>
上下文
<script setup>
import { ref, provide } from "vue";
import UserProfile from "./UserProfile.vue";
const user = ref({
id: 1,
username: "abcdefg",
email: "[email protected]",
});
function updateUsername(username) {
user.value.username = username;
}
provide("user", { user, updateUsername });
</script>
<template>
<h1>欢迎回来, {{ user.username }}</h1>
<UserProfile />
</template>
<!-- x-text 必须用在带有 x-data 的元素或其子元素上。 -->
<!-- 这两个元素可以共用一个带有 x-data 的父元素,也可以像下面这样分别添加 x-data: -->
<h1 x-data>
欢迎回来, <span x-text="$store.user.username">未知用户</span>
</h1>
<div x-data>
<h2>我的简介</h2>
<p>用户名: <span x-text="$store.user.username"></span></p>
<p>邮箱: <span x-text="$store.user.email"></span></p>
<button @click="$store.user.updateUsername('李四')">
更新用户名为 李四
</button>
</div>
<script>
document.addEventListener("alpine:init", () => {
Alpine.store("user", {
id: 1,
username: "abcdefg",
email: "[email protected]",
updateUsername(newUsername) {
this.username = newUsername;
},
});
});
</script>
表单输入
输入框
复选框
<script setup>
import { ref } from "vue";
const isAvailable = ref(true);
</script>
<template>
<input id="is-available" v-model="isAvailable" type="checkbox" />
<label for="is-available">这是一个checkbox</label>
</template>
单选框
<script setup>
import { ref } from "vue";
const picked = ref("red");
</script>
<template>
<div>你选择了: {{ picked }}</div>
<input id="blue-pill" v-model="picked" type="radio" value="blue" />
<label for="blue-pill">蓝色</label>
<input id="red-pill" v-model="picked" type="radio" value="red" />
<label for="red-pill">红色</label>
</template>
选择器
<script setup>
import { ref } from "vue";
const selectedColorId = ref(2);
const colors = [
{ id: 1, text: "红" },
{ id: 2, text: "蓝" },
{ id: 3, text: "绿" },
{ id: 4, text: "灰", isDisabled: true },
];
</script>
<template>
<select v-model="selectedColorId">
<option
v-for="color in colors"
:key="color.id"
:value="color.id"
:disabled="color.isDisabled"
>
{{ color.text }}
</option>
</select>
</template>
<div
x-data="{
selectedColorId: 2,
colors: [
{ id: 1, text: '红' },
{ id: 2, text: '蓝' },
{ id: 3, text: '绿' },
{ id: 4, text: '灰', isDisabled: true }
]
}"
>
<select x-model.number="selectedColorId">
<template x-for="color in colors" x-bind:key="color.id">
<option
x-text="color.text"
x-bind:value="color.id"
x-bind:disabled="!!color.isDisabled"
x-bind:selected="color.id === selectedColorId"
></option>
</template>
</select>
</div>
Web应用特性
渲染应用
fetch获取数据
<script setup>
import useFetchUsers from "./useFetchUsers";
const { isLoading, error, data: users } = useFetchUsers();
</script>
<template>
<p v-if="isLoading">正在获取用户信息……</p>
<p v-else-if="error">获取用户信息出错</p>
<ul v-else-if="users">
<li v-for="user in users" :key="user.login.uuid">
<img :src="user.picture.thumbnail" alt="user" />
<p>
{{ user.name.first }}
{{ user.name.last }}
</p>
</li>
</ul>
</template>
<div
x-data="
function fetchUsers() {
return {
users: null,
isLoading: false,
error: null,
async init() {
this.isLoading = true;
try {
this.users = (await (await fetch('https://randomuser.me/api/?results=3')).json()).results;
} catch (err) {
this.users = [];
this.error = err
}
this.isLoading = false;
},
};
}
"
>
<template x-if="isLoading">
<p>正在获取用户信息……</p>
</template>
<template x-if="error">
<p>获取用户信息出错</p>
</template>
<template x-if="!error">
<ul>
<template x-for="user in users">
<li>
<img
:src="user.picture.thumbnail"
:alt="`picture of ${user.name.first} ${user.name.last}`"
/>
<p x-text="`${user.name.first} ${user.name.last}`"></p>
</li>
</template>
</ul>
</template>
</div>