title: Instead, use a data or computed property based on the prop's value. Prop being mutated: "percentage"
body: <p>vue show me this problem , i dont know what happend </p>
  
  <p>my el progress </p>
  
  <pre><code>&lt;el-progress :percentage="percentCompleted" v-show="uploadingVideo"&gt;&lt;/el-progress&gt;
  </code></pre>
  
  <pre><code>data() {
  return{
        percentCompleted: 0,
  }
  }
  </code></pre>
  
  <p>my function </p>
  
  <pre><code>onUploadProgress: function(progressEvent) {
            this.percentCompleted = Math.round(
              (progressEvent.loaded * 100) / progressEvent.total
            );
            this.$forceUpdate();
          }.bind(this)
        };
  </code></pre>