知识点

mousemove与mouseenter的区别在于mousemove会触发事件冒泡，mouseenter不会，mouseleave同理。

mousemove会触发事件冒泡，因此鼠标在范围区域内移动时会一直触发。

mouseenter只触发一次，鼠标移入后触发，鼠标移出后不再触发。

<template>
  <div class="collapse">
    <!-- 固定展示区域 -->
    <div class="collapse-heade">
      <slot name="collapseHeade"></slot>
    </div>
    <!-- 动态展示区域 -->
    <div class="collapse-body" :style="{ 'height': collHeight + 'px', 'transition': 'all 0.5s ease' }">
      <slot name="collapseBody"></slot>
    </div>
    <div class="collapse-bar" @click="onSwitch">
      <div class="collapse-bar-box">
        <div class="collapse-bar-box-con">
          <i :class="['icon', icon]"></i>
          <span class="text">{{ text }}</span>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      collHeight: 0,
      show: false,
      showText: false,
      text: '展示更多',
      icon: 'el-icon-caret-bottom'
    }
  },
  mounted() {
    const box = document.querySelector('.collapse-bar-box')
    /*
    * mousemove与mouseenter的区别在于mousemove会触发事件冒泡，mouseenter不会，mouseleave同理
    * mousemove会触发事件冒泡，因此鼠标在范围区域内移动时会一直触发。
    * mouseenter只触发一次，鼠标移入后触发，鼠标移出后不再触发
    */
    box.addEventListener('mouseenter', function (ev) {
      this.querySelector('.collapse-bar-box-con').style.transform = 'translateX(-20px)'
      this.querySelector('.collapse-bar-box-con>.icon').style.color = '#36CFC9'
      this.querySelector('.collapse-bar-box-con>.text').style.opacity = '1'
    })
    box.addEventListener('mouseleave', function () {
      this.querySelector('.collapse-bar-box-con').style.transform = 'translateX(20px)'
      this.querySelector('.collapse-bar-box-con>.icon').style.color = '#d3dce6'
      this.querySelector('.collapse-bar-box-con>.text').style.opacity = '0'
    })
  },
  methods: {
    onSwitch() {
      this.show = !this.show
      if (this.show) {
        this.collHeight = 0
        const list = Array.from(document.querySelector('.collapse-body').children)
        list.forEach((item) => {
          this.collHeight += item.offsetHeight
        })
        this.icon = 'el-icon-caret-top'
        this.text = '隐藏内容'
      } else {
        this.collHeight = 0
        this.icon = 'el-icon-caret-bottom'
        this.text = '展示更多'
      }
    }
  }
}
</script>

<style lang="scss" scoped>
.collapse {
  border-radius: 3px;

  .collapse-heade {}

  .collapse-body {
    overflow: hidden;
  }

  .collapse-bar {
    height: 44px;
    width: 100%;
    padding: 0 16px;
    box-sizing: border-box;

    .collapse-bar-box {
      width: 100%;
      height: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      border: 1px solid #ebebeb;
      border-radius: 4px;
      cursor: pointer;

      .collapse-bar-box-con {
        transition: transform 0.3s;

        i {
          font-size: 16px;
          font-weight: 500;
          color: #d3dce6;
          transition: color 0.3s;
        }

        span {
          margin-left: 12px;
          font-size: 14px;
          font-weight: 400;
          color: #36CFC9;
          opacity: 0;
          transition: opacity 0.3s;
        }
      }
    }
  }
}
</style>