<div class="score">
  <Star :score="poiInfo.wm_poi_score"></Star>
</div>

<template>
 <div>
   <div class="star">
     <span class="star-item"></span>
   </div>
   <span>{{ score }}</span>
 </div>
</template>
<script>
export default {
  name: 'Star',
  props: {
    score: Number
  }
}
</script>

.star-item.on {
  background-image: url(./img/star24_on@2x.png);
}
.star-item.half {
  background-image: url(./img/star24_half@2x.png);
}
.star-item.off {
  background-image: url(./img/star24_off@2x.png);
}

<div class="star">
 <span 
  class="star-item" 
  v-for="(itemClass, index) in itemClasses"
  :key="index"
  :class="itemClass"
 >
 </span>
</div>

// 星星長度 
const LENGTH = 5

// 星星的狀態(tài)
const CLS_ON = 'on'
const CLS_HALF = 'half'
const CLS_OFF = 'off'

export default {
  name: 'Star',
  props: {
    score: Number
  },
  computed: {
    itemClasses () {
      let result = []

      let score = Math.floor(this.score * 2) / 2

      // 半星 (通過跟1取余判斷是否為小數(shù))
      let hasDecimal = score % 1 !== 0

      // 全星 （向下取整，獲取全星部分）
      let integer = Math.floor(score)

      // 遍歷全星
      for(let i = 0; i < integer; i++){
        result.push(CLS_ON)
      }

      // 處理半星
      if(hasDecimal){
        result.push(CLS_HALF)
      }

      // 補(bǔ)齊
      while(result.length < LENGTH){ // 到這里還不夠五顆星，則湊空星
        result.push(CLS_OFF)
      }

      return result
    }
  }
}