可拖动的进度条 in vue

<template>
  <div class="slider" ref="slider">
    <div class="process" :style="{width}"></div>
    <div class="thunk" ref="trunk" :style="{left}">
      <div class="block"></div>
      <!-- <div class="tips">
        <span>{{scale*100}}</span>
        <i class="fas fa-caret-down"></i>
      </div> -->
    </div>
    <!-- <div class="opacity" style="left:-21px;top:-5px;">0%</div> -->
    <div class="opacity" style=" color:#83C8FE; right:-50px;top:-5px;">{{parseInt(scale*100)}}%</div>
  </div>
</template>
<script>
/*
 * min 进度条最小值
 * max 进度条最大值
 * v-model 对当前值进行双向绑定实时显示拖拽进度
 * */
export default {
  props: {
    min: {
      type: Number,
      default: 0
    },
    max: {
      type: Number,
      default: 100
    },
    value: {
      type: String,
      default: '100'
    },
    list:{
      type:Object,
      default: {
        
      }
    }
  },
  data() {
    return {
      slider: null, //滚动条DOM元素
      thunk: null, //拖拽DOM元素
      per: this.value //当前值
    };
  },
  //渲染到页面的时候
  mounted() {
    this.slider = this.$refs.slider;
    this.thunk = this.$refs.trunk;
    var _this = this;
    this.thunk.onmousedown = function(e) {
      var width = parseInt(_this.width);
      var disX = e.clientX;
      document.onmousemove = function(e) {
        // value, left, width
        // 当value变化的时候，会通过计算属性修改left，width

        // 拖拽的时候获取的新width
        var newWidth = e.clientX - disX + width;
        // 拖拽的时候得到新的百分比
        var scale = newWidth / _this.slider.offsetWidth;
        _this.per = Math.ceil((_this.max - _this.min) * scale + _this.min);
        _this.per = Math.max(_this.per, _this.min);
        _this.per = Math.min(_this.per, _this.max);
      };
      document.onmouseup = function() {
        document.onmousemove = document.onmouseup = null;
      };
      return false;
    };
  },
  computed: {
    // 设置一个百分比，提供计算slider进度宽度和trunk的left值
    // 对应公式为  当前值-最小值/最大值-最小值 = slider进度width / slider总width
    // trunk left =  slider进度width + trunk宽度/2
    scale() {
      return (this.per - this.min) / (this.max - this.min);
    },
    width() {
      if (this.slider) {
        return this.slider.offsetWidth * this.scale + "px";
      } else {
        return 0 + "px";
      }
    },
    left() {
      if (this.slider) {
        return (
          this.slider.offsetWidth * this.scale -
          this.thunk.offsetWidth / 2 +
          "px"
        );
      } else {
        return 0 + "px";
      }
    }
  },
  watch: {
    scale(val, oldVal) {
      // console.log('per',val, oldVal)
      this.$emit("SetOpacityConfig",this.list,val);
    }
  }
};
</script>
<style>
.clear:after {
  content: "";
  display: block;
  clear: both;
}
.slider {
  position: relative;
  margin: 10px 0px 5px 25px;   
   width: 310px;
  height: 7px;
  background:rgba(255, 255, 255,0);
  border: 1px solid #83C8FE;
  border-radius: 5px;
  cursor: pointer;
}
.slider .opacity {
  position: absolute;
  font-size: 20px;
  font-family: Agency FB;
  color: rgb(255, 255, 255);
  font-weight: bold;
  line-height: 15px;
}
.slider .process {
  position: absolute;
  left: 0;
  top: 0;
  width: 112px;
  height: 5px;
  border-radius: 5px;
  background: #83C8FE;
}
.slider .thunk {
  position: absolute;
  left: 100px;
  top: -4px;
  width: 20px;
  height: 20px;
}
.slider .block {
  margin-top:-3px;
  margin-left:3px;
  width: 8px;
  height: 20px;
  border-radius: 5px;
  border: 1px solid #83C8FE;
  background: #83C8FE;
  transition: 0.2s all;
}
.slider .tips {
  position: absolute;
  left: -2px;
  bottom: 24px;
  min-width: 10px;
  text-align: center;
  padding: 0px 1px 0px 1px;
  background: #83C8FE;
  border-radius: 2px;
  height: 16px;
  line-height: 16px;
  color: #fff;
  font-weight: bold;
  font-size: 14px;
}
.slider .tips i {
  position: absolute;
  margin-left: -5px;
  left: 50%;
  bottom: -9px;
  font-size: 14px;
  color: #83C8FE;
}
.slider .block:hover {
  transform: scale(1.1);
  opacity: 0.9;
}
</style>