DropdownMenu.vue

<template>
  <div :class="{active:isActive}" class="share-dropdown-menu">
    <div class="share-dropdown-menu-wrapper">
      <span class="share-dropdown-menu-title" @click.self="clickTitle">{{ title }}</span>
      <div v-for="(item,index) of items" :key="index" class="share-dropdown-menu-item">
        <a v-if="item.href" :href="item.href" target="_blank">{{ item.title }}</a>
        <span v-else>{{ item.title }}</span>
      </div>
    </div>
  </div>
</template>

<script>
export default {
  props: {
    items: {
      type: Array,
      default: function() {
        return [];
      },
    },
    title: {
      type: String,
      default: 'vue',
    },
  },
  data() {
    return {
      isActive: false,
    };
  },
  methods: {
    clickTitle() {
      this.isActive = !this.isActive;
    },
  },
};
</script>

<style rel="stylesheet/scss" lang="scss" >
$n: 8; //和items.length 相同
$t: .1s;
.share-dropdown-menu {
  width: 250px;
  position: relative;
  z-index: 1;
  &-title {
    width: 100%;
    display: block;
    cursor: pointer;
    background: black;
    color: white;
    height: 60px;
    line-height: 60px;
    font-size: 20px;
    text-align: center;
    z-index: 2;
    transform: translate3d(0,0,0);
  }
  &-wrapper {
    position: relative;
  }
  &-item {
    text-align: center;
    position: absolute;
    width: 100%;
    background: #e0e0e0;
    line-height: 60px;
    height: 60px;
    cursor: pointer;
    font-size: 20px;
    opacity: 1;
    transition: transform 0.28s ease;
    &:hover {
      background: black;
      color: white;
    }
    @for $i from 1 through $n {
      &:nth-of-type(#{$i}) {
        z-index: -1;
        transition-delay: $i*$t;
        transform: translate3d(0, -60px, 0);
      }
    }
  }
  &.active {
    .share-dropdown-menu-wrapper {
      z-index: 1;
    }
    .share-dropdown-menu-item {
      @for $i from 1 through $n {
        &:nth-of-type(#{$i}) {
         transition-delay: ($n - $i)*$t;
          transform: translate3d(0, ($i - 1)*60px, 0);
        }
      }
    }
  }
}
</style>