index.js

import { createApp, reactive } from 'vue'

import myLoad from './Loading.vue'

const msg = reactive({
  show: false,
  title: '加载中...'
})

const $loading = createApp(myLoad, { msg }).mount(document.createElement('div'))
// console.log($loading);
const load = {
  show (title) { // 控制显示loading的方法
    msg.show = true
    msg.title = title || '加载中'
    document.body.appendChild($loading.$el)
  },

  hide () { // 控制loading隐藏的方法
    msg.show = false
  }
}

export default {
  install (app) {
    app.config.globalProperties.$loading = load
  }
}

loading.vue

<template>
  <div
    class="loading-box"
    v-show="msg.show"
  >
    <div
      class="loading-mask"
      v-show="!msg.ismask"
    ></div>
    <div class="loading-content">
      <div class="animate">
      </div>
      <div class="text">{{msg.title}}</div>
    </div>
  </div>
</template>

<script>
export default {
  props: {
    msg: Object,
  }
}
</script>

<style scoped>
.loading-box {
  position: relative;
  text-align: center;
}
.loading-mask {
  position: fixed;
  background: #000;
  opacity: 0.4;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 1000;
}
.loading-content {
  position: fixed;
  left: 50%;
  top: 50%;
  width: 1.6rem;
  min-height: 1.2rem;
  transform: translate(-50%, -50%);
  padding: 0.1rem;
  background: hsla(0, 0%, 7%, 0.7);
  text-align: center;
  border-radius: 5px;
  color: #fff;
  z-index: 5001;
}
.loading-content .animate {
  width: 0.4rem;
  height: 0.4rem;
  vertical-align: baseline;
  display: inline-block;
  margin: 0 0 0.1rem;
  vertical-align: middle;
  animation: superLoading 1s steps(12, end) infinite;
  background: transparent
    url('data:image/svg+xml;base64,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')
    no-repeat;
  background-size: 100%;
}
.loading-content .text {
  margin: 0 0 15px;
  font-size: 16px;
}
@keyframes superLoading {
  0% {
    transform: rotate3d(0, 0, 1, 0deg);
  }
  100% {
    transform: rotate3d(0, 0, 1, 360deg);
  }
}
@keyframes superLoading {
  0% {
    transform: rotate3d(0, 0, 1, 0deg);
  }
  100% {
    transform: rotate3d(0, 0, 1, 360deg);
  }
}
</style>

main.js

import Loading from './components/loading'
const app = createApp(App);
app.use(router).use(Loading).mount('#app')

页面使用

import {  getCurrentInstance } from 'vue'
 const instance = getCurrentInstance();
    instance.proxy.$loading.show();
    instance.proxy.$loading.hide();