el-upload function custom parameter passing method (custom parameter passing)

  <el-upload
                 class="upload-demo"
                 action="https://jsonplaceholder.typicode.com/posts/"
                :file-list="item.fileGroup"
                :on-preview="(file)=>{return handlePreview(file,index)}"              
                :on-remove="(file, fileList)=>{return handleRemove(file, fileList, index)}"
                :on-success="(response, file, fileList)=>{return handleSuccess(response, file, fileList, index)}"
                :before-remove="(file, fileList)=>{return beforeRemove(file, fileList, index)}"
                 multiple
                :limit="3"
                :on-exceed="(file, fileList)=>{return handleExceed(file, fileList, index)}"
              >
                <el-button size="small" type="primary">添加附件</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> 

    handleRemove(file, fileList,index) {

       console.log(file, fileList,index);

    },

    handlePreview(file,index) {

      console.log(file,index);

    },

    handleSuccess(res, file,fileList, index) {

      console.log(res, file,fileList,index);

      // this.fileType=file.type

      // this.flieName=file.name

      // this.fileID=res.data.id

      // this.flieKey=index

      // this.loginForm.items1[index].fileList.push({

      //   name: file.name,

      //   url: res.data.url

      // })

    },

    handleExceed(files, fileList,index) {

      this.$message.warning(`The current limit is to select 3 files, this time ${files.length} files are selected, a total of ${files.length + fileList.length} files are selected`);

    },

    beforeRemove(file, fileList,index) {

      return this.$confirm(`Are you sure to remove ${ file.name }?`);

    }