VueJS进度条宽度百分比

Question

所以我要尝试做的是，当我第一次点击时，进度栏的宽度为37.5％，而当我第二次点击时，百分比上升为100％，而不是0。有人可以解释为什么？这是我的代码：

HTML：

  <div class="progress-bar progress-bar-striped bg-success progress-bar-animated" role="progressbar" aria-valuemin="0" aria-valuemax="8000" :style="{width: enemyBar + '%'}">
    <strong>HP: \{{enemyHealth}} / 100</strong> 
  </div>

VUEJS：

               this.enemyBar = this.damage / this.enemyHealth*100;
               //damage: 3000 health: 5000 and progressbar left with 37.5 percent of width.
                if(this.enemyBar < 0) {
                    return this.enemyBar = 0;
                }
                if(this.enemyBar > 100) {
                    return this.enemyBar = 100;
                }                    
                this.enemyHealth -= this.damage;
                if(this.enemyHealth < 0) {
                    return this.enemyHealth = 0;
                }