响应式

声明状态

Vue 3 标志 Vue 3

<script setup>
import { ref } from "vue";
const name = ref("张三");
</script>

<template>
  <h1>你好 {{ name }}</h1>
</template>

Marko 标志 Marko

<let/name="张三">
<h1>你好 ${name}</h1>

更新状态

Vue 3 标志 Vue 3

<script setup>
import { ref } from "vue";
const name = ref("张三");
name.value = "李四";
</script>

<template>
  <h1>你好 {{ name }}</h1>
</template>

Marko 标志 Marko

<let/name="张三">
<script>name = "李四"</script>
<h1>你好 ${name}</h1>

计算属性

Vue 3 标志 Vue 3

<script setup>
import { ref, computed } from "vue";
const count = ref(10);
const doubleCount = computed(() => count.value * 2);
</script>

<template>
  <div>{{ doubleCount }}</div>
</template>

Marko 标志 Marko

<let/count=10>
<const/doubleCount=count * 2>
<div>${doubleCount}</div>

模板语法

最简模板

Vue 3 标志 Vue 3

<template>
  <h1>你好,世界</h1>
</template>

Marko 标志 Marko

<h1>你好,世界</h1>

样式

Vue 3 标志 Vue 3

<template>
  <h1 class="title">我是红色的</h1>
  <button style="font-size: 10rem">我是一个按钮</button>
</template>

<style scoped>
.title {
  color: red;
}
</style>

Marko 标志 Marko

<h1.title>我是红色的</h1>
<button style={ "font-size": "10rem" }>我是一个按钮</button>
<button class=scopedButton>我是一个样式作用域按钮</button>

<style>
  .title {
    color: red;
  }
</style>
<style/{ scopedButton }>
  .scopedButton {
    font-size: 10rem;
  }
</style>

DOM循环

Vue 3 标志 Vue 3

<script setup>
const colors = ["红", "绿", "蓝"];
</script>

<template>
  <ul>
    <li v-for="color in colors" :key="color">
      {{ color }}
    </li>
  </ul>
</template>

Marko 标志 Marko

<ul>
  <for|color| of=["红", "绿", "蓝"]>
    <li>${color}</li>
  </for>
</ul>

点击事件

Vue 3 标志 Vue 3

<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>

Marko 标志 Marko

<let/count=0>
<p>计数器: ${count}</p>
<button onClick() { count++ }>+1</button>

DOM引用

Vue 3 标志 Vue 3

<script setup>
import { useTemplateRef, onMounted } from "vue";

const inputElement = useTemplateRef("inputElement");

onMounted(() => {
  inputElement.value.focus();
});
</script>

<template>
  <input ref="inputElement" />
</template>

Marko 标志 Marko

<input/inputElement>
<script>
  inputElement().focus();
</script>

条件渲染

Vue 3 标志 Vue 3

<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>

Marko 标志 Marko

static const TRAFFIC_LIGHTS = ["红灯", "黄灯", "绿灯"];
<let/lightIndex=0>
<const/light=TRAFFIC_LIGHTS[lightIndex]>

<button onClick() { lightIndex = (lightIndex + 1) % TRAFFIC_LIGHTS.length }>
  下一个灯
</button>
<p>现在亮着的是: ${light}</p>
<p>
  你应该
  <if=light === "红灯">停下</if>
  <else if=light === "黄灯">慢行</else>
  <else>赶紧走</else>
</p>

生命周期

组件加载时

Vue 3 标志 Vue 3

<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>

Marko 标志 Marko

<let/pageTitle="">
<script>pageTitle = document.title</script>
<p>页面标题: ${pageTitle}</p>

组件卸载时

Vue 3 标志 Vue 3

<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>

Marko 标志 Marko

<let/time=new Date()>
<script>
  const id = setInterval(() => time = new Date(), 1000);
  $signal.onabort = () => clearInterval(id)
</script>
<p>当前时间: ${time.toLocaleTimeString()}</p>

组件组合

组件Props传参

Vue 3 标志 Vue 3

<script setup>
import UserProfile from "./UserProfile.vue";
</script>

<template>
  <UserProfile
    name="张三"
    :age="20"
    :favourite-colors="['green', 'blue', 'red']"
    is-available
  />
</template>

Marko 标志 Marko

<UserProfile
  name="张三"
  age=20
  favouriteColors=["green", "blue", "red"]
  isAvailable
/>

向父组件emit事件

Vue 3 标志 Vue 3

<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>

Marko 标志 Marko

<let/isHappy=true>
<p>你快乐吗?</p>
<AnswerButton
  onYes() { isHappy = true }
  onNo() { isHappy = false }
/>
<p style={ "font-size": 50 }>${isHappy ? "😀" : "😥"}</p>

slot插槽

Vue 3 标志 Vue 3

<script setup>
import FunnyButton from "./FunnyButton.vue";
</script>

<template>
  <FunnyButton> 点我! </FunnyButton>
</template>

Marko 标志 Marko

<FunnyButton>点我!</FunnyButton>

slot插槽内容

Vue 3 标志 Vue 3

<script setup>
import FunnyButton from "./FunnyButton.vue";
</script>

<template>
  <FunnyButton />
  <FunnyButton> 这是传到slot的内容! </FunnyButton>
</template>

Marko 标志 Marko

<FunnyButton/>
<FunnyButton>这是传到slot的内容!</FunnyButton>

上下文

Vue 3 标志 Vue 3

<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>

Marko 标志 Marko

<let/user={
  id: 1,
  username: "abcdefg",
  email: "[email protected]",
}>
<const/updateUsername(newUsername) {
  user = { ...user, username: newUsername };
}>

<h1>欢迎回来, ${user.username}</h1>
<context={ ...user, updateUsername }>
  <UserProfile />
</context>

表单输入

输入框

Vue 3 标志 Vue 3

<script setup>
import { ref } from "vue";
const text = ref("你好世界");
</script>

<template>
  <p>{{ text }}</p>
  <input v-model="text" />
</template>

Marko 标志 Marko

<let/text="你好世界">
<p>${text}</p>
<input value:=text>

复选框

Vue 3 标志 Vue 3

<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>

Marko 标志 Marko

<input#is-available
  type="checkbox"
  checked:=input.isAvailable
>
<label for="is-available">这是一个checkbox</label>

单选框

Vue 3 标志 Vue 3

<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>

Marko 标志 Marko

<let/picked="red">

<div>你选择了: ${picked}</div>
<input#blue-pill
  type="radio"
  value="blue"
  checkedValue:=picked
>
<label for="blue-pill">蓝色</label>

<input#red-pill
  type="radio"
  value="red"
  checkedValue:=picked
>
<label for="red-pill">红色</label>

选择器

Vue 3 标志 Vue 3

<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>

Marko 标志 Marko

static const colors = [
  { id: 1, text: "红" },
  { id: 2, text: "蓝" },
  { id: 3, text: "绿" },
  { id: 4, text: "灰", isDisabled: true },
];
<let/selectedColorId=2>

<select value:=selectedColorId>
  <for|{ id, isDisabled, text }| of=colors>
    <option value=id disabled=isDisabled>
      ${text}
    </option>
  </for>
</select>

Web应用特性

渲染应用

Vue 3 标志 Vue 3

<!doctype html>
<html>
  <body>
    <div id="app"></div>
    <script type="module" src="./main.js"></script>
  </body>
</html>

Marko 标志 Marko

<!doctype html>
<html>
  <body>
    <div id="app"></div>
    <script type="module" src="./app.js"></script>
  </body>
</html>

fetch获取数据

Vue 3 标志 Vue 3

<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>

Marko 标志 Marko

<try>
  <await|{ results: users }|=fetch("https://randomuser.me/api/?results=3").then(res => res.json())>
    <ul>
      <for|{ picture, name }| of=users>
        <li>
          <img src=picture.thumbnail alt="user">
          <p>${name.first} ${name.last}</p>
        </li>
      </for>
    </ul>
  </await>
  <@placeholder>
    <p>正在获取用户信息……</p>
  </@placeholder>
  <@catch|error|>
    <p>获取用户信息出错</p>
  </@catch>
</try>