md/src/App.vue

<template>
    <transition name="fade" v-if="loading">
        <loading />
    </transition>
    <codemirror-editor v-else />
</template>

<script>
import Loading from "./components/Loading";
import CodemirrorEditor from "./view/CodemirrorEditor";
export default {
    name: "App",
    components: {
        Loading,
        CodemirrorEditor,
    },
    data() {
        return {
            loading: true,
        };
    },
    mounted() {
        setTimeout(() => {
            this.loading = false;
        }, 100);
    },
};
</script>

<style lang="scss" scoped>
.fade-enter,
.fade-leave-to {
    opacity: 0;
}
.fade-enter-to,
.fade-leave {
    opacity: 1;
}
.fade-enter-active,
.fade-leave-active {
    transition: all 1s;
}
</style>