Vue3-js 学习笔记
目录
- reactive 数据绑定
- 事件绑定
- 生命函数周期
- 计算属性-computed
- props
- emit-自定义事件
- ref-获取元素及子组件
- watch
- vue3-组件通信
- reactive-ref-区别
前言
优秀的教程
reactive 数据绑定
<template>
<div class="app">
<h1>{{ state.name }}</h1>
</div>
</template>
<script>
import { reactive } from "vue";
export default {
name: "App",
setup() {
const state = reactive({
name: "朱大常",
});
return { state };
},
};
</script>
事件绑定
<template>
<div class="app">
<h1>{{ state.name }}</h1>
<button type="button" @click="login">按钮</button>
</div>
</template>
<script>
import { reactive } from "vue";
export default {
name: "App",
setup() {
// 数据定义
const state = reactive({
name: "朱大常",
});
// 事件定义
const login = () => {
state.name = "朱大常001";
};
return { state, login };
},
};
</script>
生命函数周期
onMounted
<template>
<div class="app"></div>
</template>
<script>
import { onMounted } from "vue";
export default {
name: "App",
setup() {
// 组件加载
onMounted(() => {
console.log("组件已挂载");
});
},
};
</script>
计算属性-computed
computed (只要监听的那个数据改变，就会重新计算)
<template>
<div class="app">
<h1>{{ state.name }}</h1>
<h2>岁数:{{ state.age }}</h2>
<h3>计算后的属性:{{ state.setComputed }}</h3>
<input type="text" v-model="state.username" />
<button type="button" @click="login">按钮</button>
</div>
</template>
<script>
import { reactive, computed } from "vue";
export default {
name: "App",
setup() {
// 数据定义
const state = reactive({
name: "朱大常",
username: "",
age: 18,
setComputed: computed(() => state.age + 2),
});
// 事件定义
const login = () => {
state.name = state.username;
};
setTimeout(() => {
state.age = 19;
}, 2000);
return { state, login };
},
};
</script>
props
<!-- 子组件 -->
<template>
<h1>子组件：{{ title }}</h1>
</template>
<script>
import { onMounted } from "vue";
export default {
name: "test",
props: {
title: {
type: String,
default: "",
},
},
setup(props) {
onMounted(() => {
console.log("----组件加载完成-props值为", props.title);
});
},
};
</script>
<!-- 父组件 -->
<template>
<div class="app">
<test :title="state.title"></test>
</div>
</template>
<script>
import { reactive } from "vue";
import test from "./components/test";
export default {
name: "App",
components: {
test,
},
setup(props) {
// 数据定义
const state = reactive({
title: "朱大常",
});
return { state };
},
};
</script>
emit-自定义事件
emit 传值-注意这里的事件生命使用小写加-
<!-- 子组件 -->
<template>
<button type="button" @click="handleClick">emit按钮</button>
</template>
<script>
import { onMounted } from "vue";
export default {
name: "test",
setup({ emit }) {
const handleClick = () => {
emit("my-event", "hello");
};
return { handleClick };
},
};
</script>
<!-- 父组件 -->
<template>
<div class="app">
<test @my-event="parentClick"></test>
</div>
</template>
<script>
import { reactive } from "vue";
import test from "./components/test";
export default {
name: "App",
components: {
test,
},
setup(props) {
// 数据定义
const state = reactive({
name: "朱大常",
});
const parentClick = (e) => {
console.log(e);
};
return { parentClick };
},
};
</script>
ref-获取元素及子组件
ref 注意-相比 vue2.x 有很大的改变--ref 和 reactive 差别-ref 线
<!-- 子组件 -->
<template>
<div></div>
</template>
<script>
import { ref } from "vue";
export default {
name: "test",
setup() {
// 1. 定义响应式的数据
const count = ref(1);
// 2. 定义方法
const refsgh = () => {
console.log("-----k");
};
return { count, refsgh };
},
};
</script>
<!-- 父组件 -->
<template>
<div class="app">
<test ref="comRef"></test>
<button @click="clickClid001">获取子组成数据</button>
<button @click="clickClid002">调用子组件方法</button>
</div>
</template>
<script>
import { ref } from "vue";
import test from "./components/test";
export default {
name: "App",
components: {
test,
},
setup() {
// 1. 创建一个组件的 ref 引用
const comRef = ref(null);
// 2. 获取子组成的值
const clickClid001 = () => {
console.log(comRef.value.count);
};
// 3. 调用子组件的方法
const clickClid002 = () => {
comRef.value.refsgh();
};
return { comRef, clickClid001, clickClid002 };
},
};
</script>
watch
<template>
<div class="app">
<button @click="watch001">watch方法</button>
<!-- 这里.value可以省略 -->
<h4>ref值:{{ nameref }}</h4>
</div>
</template>
<script>
import { watch } from "vue";
export default {
name: "App",
setup() {
const nameref = ref("朱大常");
watch(nameref, (newValue, oldValue) => {
// 输出 前端有的玩 子君
console.log(newValue, oldValue);
});
const watch001 = () => {
nameref.value = "张德帅";
};
return {
watch001,
nameref,
};
},
};
</script>