vue3_0">1.vue3中变量写法

import { reactive} from "vue";
export default {
  setup() {
    const state = reactive({
      value: "",
      ids: "",
      bannerImg: "",
      sightName: "",
      gallaryImgs: [],
      categoryList: []
    });
    //注意return出去
    return { state};
  }
 }

//在template中的变量前面加state
<p class="sightName">{{state.sightName}}</p>

vue3state_24">2.vue3变量省略state

//引入toRefs在return是...toRefs（state）就可以了
import { reactive,toRefs} from "vue";
export default {
  setup() {
    const state = reactive({
      value: "",
      ids: "",
      bannerImg: "",
      sightName: "",
      gallaryImgs: [],
      categoryList: []
    });
    
    return { ...toRefs(state)};
  }
};

<p class="sightName">{{sightName}}</p>

vue3this_47">3.vue3中不能用this

import { reactive,getCurrentInstance} from "vue";
export default {
  setup() {
    const state = reactive({
      value: "",
      ids: "",
      bannerImg: "",
      sightName: "",
      gallaryImgs: [],
      categoryList: []
    });
    //ctx就和vue2中this是一样的
    const { ctx } = getCurrentInstance();
    const go = () => {
      ctx.$router.go("-1");
    };
    return { state, go};
  }
};

vue3_70">4.vue3中事件

	<p class="go" @click="go">
        <van-icon name="arrow-left" />
      </p>

import { reactive,getCurrentInstance} from "vue";
export default {
  setup() {
  	const { ctx } = getCurrentInstance()
    const go = () => {
      ctx.$router.go("-1");
    };
    return { state, go};
  }
 }

vue3_91">5.vue3生命周期

import { reactive, onMounted} from "vue";
export default {
  setup() {
    onMounted(() => {
      ctx.$axios.get("/mock/detail.json").then(res => {
        console.log(res);
        state.bannerImg = res.data.data.bannerImg;
        state.gallaryImgs = res.data.data.gallaryImgs;
        state.sightName = res.data.data.sightName;
        state.categoryList = res.data.data.categoryList;
      });
    });
    return { state, onMounted};
  }
};

vue3axios_109">6.vue3安装axios

通过指令 npm install axios -S 安装axios和指令npm install vue-axios -S
安装vue-axios(注意：有时候我们在pack.json中看到vue-axios已经安装上去了，但是可能存在明明安装了，在组件中无法使用，因此需要重新安装vue-axios,这个在vue3.0中有80%的几率发生)

//在main.js全局配置axios
const app = createApp(App)
app.config.globalProperties.$axios = axios

vue3refrefvue2refvu3refvue2refDom_119">6.vue3ref（注意这个ref和vue2中的ref不一样，千万别弄混了，vu3中的ref是给定的值创建一个响应式的数据对象。vue2中的ref是获取Dom元素）

//自增
import {reactive, ref} from "vue";
export default {
  name: "Home",
  setup() {
    const state = reactive({
      value: "",
    });
    const count = ref(11111)
    return { state,count };
  }