vue

<el-upload drag action="#" :multiple=multiple ref="upload" list-type="file"
               :show-file-list="false" :http-request="uploadFa" :before-upload="beforeExcelUpload">
      <i class="el-icon-upload"></i>
      <div class="el-upload__text">将.fa或者.fasta文件拖到此处，或<em>点击上传</em></div>
      <div class="el-upload__tip" slot="tip">只能上传.txt文件或.fa文件</div>
    </el-upload>

uploadFa(item) {
        this.readFile(item.file)
        // 处理文件上传
      },
readFile(file) {
        console.info(file.name)
        const reader = new FileReader()
        reader.onload = e => this.$emit('load', this.dealNum(e.target.result))
        reader.readAsBinaryString(file)
      },
      dealNum(item) {
        console.log(item)
        // 将item展示到需要地方
      },
      beforeExcelUpload(file) {
        const isLt200K = file.size / 1024 < 200
        if (!isLt200K) {
          this.$message.error('上传文件大小不能超过 200k!')
        }
        return isLt200K
      }