笨方法实现数量的输入与加一减一 、以及对边界值的判断禁用

如图：

data(){
return {

　　　prodNum: 1, //计数器数量

      prohibit1: false,  //计数器-是否禁用

      prohibit2: false,  //计数器+是否禁用

}


函数：
// 笨方法实现数量的输入与加一减一
    // 以及对边界值的判断禁用
    /**
     * 减少商品数量
     */
    reduce () {
      var prodNum = parseInt(this.prodNum)
      if (prodNum == 1) {
        this.prohibit1 = true  //禁用
      } else {
        this.prodNum = prodNum - 1
        this.judgeInput()
      }
    },

    /*
    * 失去焦点时对输入框的判断
    */ 
    judgeInput (e) {
      var prodNum = this.prodNum
      if (prodNum.length == 0 || prodNum == 0) {
        this.prodNum = 1
      } else if (prodNum > this.prodInfo.totalStocks) {
        this.$message({
          message: '限购' + this.prodInfo.totalStocks + '件',
          type: 'warning',
          duration: 1000
        });
        this.prodNum = this.prodInfo.totalStocks
        this.prohibit1 = false
        this.prohibit2 = true  //禁用
      } else {
        this.prodNum = prodNum
        this.prohibit2 = false  //禁用
      }
    },


    /**
     * 增加商品数量
     */
    increase () {
      var prodNum = this.prodNum
      // 判断是否限购
      if (this.prodInfo.totalStocks) {
        if (prodNum < this.prodInfo.totalStocks) {
          this.prodNum = parseInt(prodNum) + 1
          this.prohibit2 = false  //禁用
        } else {
          this.$message({
            message: '限购' + this.prodInfo.totalStocks + '件',
            type: 'warning',
            duration: 1000
          });
          this.prohibit2 = true  //禁用
          this.prodNum = this.prodInfo.totalStocks
        }
      } else {
        return
      }
      this.prohibit1 = false
    },

html：

<div class="items">
              <span class="tit">数量</span>
              <div class="con">
                <div class="goods-number" onselectstart="return false">
                  <span :class="['reduce', this.prohibit1?'limit':'']" @click="reduce">-</span>
                  <input
                    type="number"
                    class="number"
                    v-model="prodNum"
                    oninput="value=value.replace(/[^d]/g,'')"
                    @blur="judgeInput"
                  />
                  <span :class="['increase', this.prohibit2?'limit':'']" @click="increase">+</span>
                </div>
              </div>
            </div>

.items .con .goods-number {
    height: 30px;
}

.items .con .goods-number .reduce,
.items .con .goods-number .increase {
    display: inline-block;
    vertical-align: top;
     30px;
    height: 30px;
    background: #e9e9e9;
    font-size: 22px;
    text-align: center;
    line-height: 26px;
    color: #999;
    cursor: pointer;
}

.items .con .goods-number .limit {
    cursor: not-allowed;
    color: #ccc;
    background: rgb(246, 246, 246, .7);
}

.items .con .goods-number .number {
    border: 0;
     50px;
    height: 30px;
    text-align: center;
    font-family: arial;
    vertical-align: top;
    /* background: rgb(245, 245, 245, .4); */
}