(精華)2020年7月17日 vue 實現回到頂部

<template>
  <transition :name="transitionName">
    <div v-show="visible" :style="customStyle" class="back-to-ceiling" @click="backToTop">
      <svg width="16" height="16" viewBox="0 0 17 17" xmlns="http://www.w3.org/2000/svg" class="Icon Icon--backToTopArrow" aria-hidden="true" style="height:16px;width:16px"><path d="M12.036 15.59a1 1 0 0 1-.997.995H5.032a.996.996 0 0 1-.997-.996V8.584H1.03c-1.1 0-1.36-.633-.578-1.416L7.33.29a1.003 1.003 0 0 1 1.412 0l6.878 6.88c.782.78.523 1.415-.58 1.415h-3.004v7.004z" /></svg>
    </div>
  </transition>
</template>

<script>
export default { 
 
  
  name: 'BackToTop',
  props: { 
 
  
    visibilityHeight: { 
 
  
      type: Number,
      default: 400
    },
    backPosition: { 
 
  
      type: Number,
      default: 0
    },
    customStyle: { 
 
  
      type: Object,
      default: function() { 
 
  
        return { 
 
  
          right: '50px',
          bottom: '50px',
          width: '40px',
          height: '40px',
          'border-radius': '4px',
          'line-height': '45px',
          background: '#e7eaf1'
        }
      }
    },
    transitionName: { 
 
  
      type: String,
      default: 'fade'
    }
  },
  data() { 
 
  
    return { 
 
  
      visible: false,
      interval: null,
      isMoving: false
    }
  },
  mounted() { 
 
  
    window.addEventListener('scroll', this.handleScroll)
  },
  beforeDestroy() { 
 
  
    window.removeEventListener('scroll', this.handleScroll)
    if (this.interval) { 
 
  
      clearInterval(this.interval)
    }
  },
  methods: { 
 
  
    handleScroll() { 
 
  
      this.visible = window.pageYOffset > this.visibilityHeight
    },
    backToTop() { 
 
  
      if (this.isMoving) return
      const start = window.pageYOffset
      let i = 0
      this.isMoving = true
      this.interval = setInterval(() => { 
 
  
        const next = Math.floor(this.easeInOutQuad(10 * i, start, -start, 500))
        if (next <= this.backPosition) { 
 
  
          window.scrollTo(0, this.backPosition)
          clearInterval(this.interval)
          this.isMoving = false
        } else { 
 
  
          window.scrollTo(0, next)
        }
        i++
      }, 16.7)
    },
    easeInOutQuad(t, b, c, d) { 
 
  
      if ((t /= d / 2) < 1) return c / 2 * t * t + b
      return -c / 2 * (--t * (t - 2) - 1) + b
    }
  }
}
</script>

<style scoped>
.back-to-ceiling { 
 
  
  position: fixed;
  display: inline-block;
  text-align: center;
  cursor: pointer;
}

.back-to-ceiling:hover { 
 
  
  background: #d5dbe7;
}

.fade-enter-active,
.fade-leave-active { 
 
  
  transition: opacity .5s;
}

.fade-enter,
.fade-leave-to { 
 
  
  opacity: 0
}

.back-to-ceiling .Icon { 
 
  
  fill: #9aaabf;
  background: none;
}
</style>

<template>
  <div class="components-container">
    <div class="placeholder-container">
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
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      <div>placeholder</div>
      <div>placeholder</div>
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      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
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      <div>placeholder</div>
      <div>placeholder</div>
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      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
      <div>placeholder</div>
    </div>
    <!-- you can add element-ui's tooltip -->
    <el-tooltip placement="top" content="tooltip">
      <back-to-top :custom-style="myBackToTopStyle" :visibility-height="300" :back-position="50" transition-name="fade" />
    </el-tooltip>
  </div>
</template>

<script>
import BackToTop from '@/components/BackToTop'

export default { 
 
  
  name: 'BackToTopDemo',
  components: { 
 
   BackToTop },
  data() { 
 
  
    return { 
 
  
      // customizable button style, show/hide critical point, return position
      myBackToTopStyle: { 
 
  
        right: '50px',
        bottom: '50px',
        width: '40px',
        height: '40px',
        'border-radius': '4px',
        'line-height': '45px', // 請保持與高度一致以垂直居中 Please keep consistent with height to center vertically
        background: '#e7eaf1'// 按鈕的背景顏色 The background color of the button
      }
    }
  }
}
</script>

<style scoped>
.placeholder-container div { 
 
  
  margin: 10px;
}
</style>