文件上传前无法修改文件名

[louxu623]

文件上传组件：
<wd-upload
v-model="planForm.fileList"
multiple
:limit="3"
:before-upload="imgBeforeUpload"
@exceed="imgUploadLimit"
@success="imgUploadSuccess"
@remove="imgRemoveSuccess"
:action="uploadUrl">

上传文件之前的钩子:
imgBeforeUpload ({ files, fileList, resolve }) {
for (let i = 0; i < files.length; i++) {
console.log(files[i].name);
let suffix = files[i].name.substring(files[i].name.lastIndexOf(".")); //.txt
files[i].name = 'dispatch-' + this.generateUniqueString() + suffix
console.log(customFile.name)
}
resolve(true)
},

以上，文件名修改不生效，各种方法都尝试过了。麻烦帮忙看看是啥原因哦，感谢！