element 自定义上传函数，删除文件报错问题

点击删除按钮报错：reqs[uid].abort is not a function

解决方法：

在http-request函数中写上如下代码就不会再报上述错误。：

const prom = new Promise((resolve, reject) => {})
prom.abort = () => {}
return prom

element代码：注意 before-remove需要写

<el-upload
        ref="upload"
        class="file-upload"
        :data="extraData"
        :on-remove="delFileList"
        :before-upload="handleBeforeUpload"
        :before-remove="handleRemove"
        :on-success="getSuccessFile"
        :on-exceed="handleExceed"
        :file-list="files"
        :accept="accept.join(',')"
        drag
        :action="action"
        :http-request="uploadS3"
        multiple
        :limit="limit">
        <i class="el-icon-upload"></i>
        <div class="el-upload__text">将文件拖到此处，或
          <em>点击上传</em>
        </div>
        <div class="el-upload__tip" slot="tip">支持{{ accept.join(',') }}文件，{{ limitText }}</div>
      </el-upload>

uploadS3代码：

uploadS3(param) {
    xxxxx
    const prom = new Promise((resolve, reject) => {
    })
    prom.abort = () => {
    }
    return prom
},
handleRemove(){
    console.log('remove');
    this.$refs.upload.clearFiles();
},