Back-To-Top组件

Back-To-Top
在vue中使用Back-To-Top组件，方便用户快速回到页面顶部。

属性
custom-style 自定义组件样式
visibility-height 页面滚动条滚动到指定值后显示组件，默认值400
back-position 点击后回到顶部的位置，默认值0
transition-name 设置组件transition的name属性，默认值’fade’

组件代码

<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
      this.scrollTop = window.pageYOffset;
    },
    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 lang="scss" scoped>
.back-to-ceiling {
  position: fixed;
  display: inline-block;
  text-align: center;
  cursor: pointer;
  opacity: .4;
  transition: opacity .3s;
  &:hover{
    opacity: 1;
  }
  .Icon{
    fill: #9aaabf;
    background: none;
  }
}

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

.fade-enter,
.fade-leave-to {
  opacity: 0
}
</style>

使用

<back-to-top :custom-style="myBackToTopStyle" :visibility-height="300" :back-position="50" transition-name="fade"/>

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', // 请保持与高度一致以垂直居中 Please keep consistent with height to center vertically
      background: '#e7eaf1'// 按钮的背景颜色 The background color of the button
    }
  }
},