element upload 钩子函数的坑及解决

success () {
  this.$message.success('上传成功')
}

<el-upload
        class="upload-demo"
        ref="upload"
        drag
        :action="uploadBusinessType"
        accept=".xls, .xlsx, .csv"
        :auto-upload="false"
        :on-success="handleAvatarSuccess"
        multiple
      >

handleAvatarSuccess(...params) {
    ‘这里代码就不在表述'
    }

//上传组件
<el-upload
  class="upload-demo"
  action="https://jsonplaceholder.typicode.com/posts/"
  :on-preview="handlePreview"
  :on-remove="handleRemove"
  :before-remove="**beforeRemove**"
  multiple
  :limit="3"
  :on-exceed="handleExceed"
  :file-list="fileList">
  <el-button size="small" type="primary">点击上传</el-button>
  <div slot="tip" class="el-upload__tip">只能上传jpg/png文件，且不超过500kb</div>
</el-upload>

beforeRemove（file, fileList）{
//就这两参数
}

//上传组件
<el-upload
  class="upload-demo"
  action="https://jsonplaceholder.typicode.com/posts/"
  :on-preview="handlePreview"
  :on-remove="handleRemove"
  :before-remove="（file,fileList）=>{
     return beforeRemove（file,fileList,data）
}"
  multiple
  :limit="3"
  :on-exceed="handleExceed"
  :file-list="fileList">
  <el-button size="small" type="primary">点击上传</el-button>
  <div slot="tip" class="el-upload__tip">只能上传jpg/png文件，且不超过500kb</div>
</el-upload>

beforeRemove（file,fileList,data）{
debugger
}