<div class="pagination" @click="pageClick">
    <button class="pre">上一页</button>
    <ul class="pages">
      <li :class="['first', { 'active' : current == 1 }]" v-if="total">
        1
      </li>
      <li :class="[ testLeft,goback]"
        v-show="showPreMore"
        @mouseenter="testLeft='more-left'"
        @mouseleave="testLeft='more'"></li>
      <li :class="['page-item', { 'active' : current == item }]" v-for="item in $pages">
        {{ item }}
      </li>
      <li :class="[ testRight,gogo]" 
        v-show="showNextMore"
        @mouseenter="testRight='more-right'"
        @mouseleave="testRight='more'"></li>
      <li :class="['last', { 'active' : current == $last }]" v-if="total">
        {{ $last }}
      </li>
    </ul>
    <button class="next">下一页</button>
  </div>

computed:{
    // 中间页数组
    $pages(){
      const foldPage = this.foldPage 
      const current = Number(this.current)
      const halfFoldPage = Math.floor((foldPage-2)/2) 
      if (this.$last > foldPage){
        if (current - halfFoldPage > 2){
          this.showPreMore = true
        }else {
          this.showPreMore = false
        }
        if (current + halfFoldPage < this.$last){
          this.showNextMore = true
        }else {
          this.showNextMore = false
        }
      }
      let array = []
      // folder1显示
      if (this.showNextMore && !this.showPreMore){
        for(let i = 2; i < foldPage; i++){
          array.push(i)
        }
      // folder1 和 folder2都显示
      }else if ( this.showPreMore && this.showNextMore ){
        for(let i = current - halfFoldPage; i <= current + halfFoldPage; i++ ){
          array.push(i)
        }
      // folder2显示
      }else if (!this.showNextMore && this.showPreMore){
        // 当folder2显示的时候,页码不能大于$last,需要往前多显示差额
        let dis = current + halfFoldPage - this.$last + 1;
        for(let i = current - halfFoldPage - dis ; i < this.$last; i++){
          array.push(i)
        }
      // 都不显示
      }else {
        for(let i = 2; i < this.$last; i++){
          array.push(i)
        }
      }
      return array
    },
    // 总页数
    $last(){             
      return Math.ceil(this.total/this.size)
    }
  }

methods:{
    pageClick(e){
      let newPage = Number(e.target.textContent)
      this.current = Number(this.current);

      if (!isNaN(newPage) && newPage){
        this.current = newPage
      }else {
        // 下一页
        if (e.target.className.indexOf('next') != -1){
          if (this.current == this.$last){
            return;
          }
          this.current ++
        }
        // 上一页
        else if (e.target.className.indexOf('pre') != -1){
          if (this.current == 1){
            return
          }
          this.current --
        }
        // 省略向左
        else if (e.target.className.indexOf('left') != -1){
          this.current -= this.foldPage - 2

          if (this.current <= 1){
            this.current = 1
            return
          }
        }
        // 省略向右
        else if(e.target.className.indexOf('right') != -1){
          this.current += this.foldPage - 2
          
          if (this.current >= this.$last){
            this.current = this.$last
            return 
          }
        }

      }
    }
  },