el-upload組件限制上傳個數

element上傳文件需要限制上傳個數，結合limit和:on-exceed去處理。

<el-upload 
         ref="upload" 
         :action="uploadUrl()"
         multiple
         :limit="5"
         :on-preview="handlePreview"
         :on-remove="handleRemove"
         :file-list="fileList"
         :on-success="uploadSuccess"
         :on-exceed="masterFileMax"
         :before-remove="beforeRemove">
         <el-button size="mini">上傳附件</el-button>
 </el-upload>

　　

methods: {
      masterFileMax(files, fileList) {
            console.log(files, fileList);
            this.$message.warning(`請最多上傳 ${this.limit} 個文件。`);
        }
}