[Feature Request] [el-upload] create file URL after before Upload

[Senasiko]

Existing Component

是

Component Name

el-upload

Description

如果默认的 listType 为 ''，然后在 beforeUpload 回调里通过 file.type 修改 listType，此时并不会生成 file url。

现在 upload 组件的上传流程为 [upload.vue].uploadFiles -> [index.vue].handleStart -> [upload.vue].upload -> [index.vue].beforeUpload。
是否创建 file url 是在 [index.vue].handleStart 中通过 listType 判断的，然而组件外在 [index.vue].beforeUpload 才会首次拿到 file 对象。
故希望在 beforeUpload 回调之后创建 file url，或者有更好的方案，谢谢。

[element-bot]

Translation of this issue:

Existing Component
yes

Component Name
El-upload

Description
If the default listType'is', and then file.type' is modified in the beforeUpload'callback by `file.type', then the file URL is not generated.

Now upload component upload process is [upload.vue]. upload Files - > [index.vue]. handleStart - > [upload.vue]. upload - > [index.vue]. beforeupload .
Whether to create a file URL is judged by listType'in [index.vue]. handleStart', but the external `[index.vue]. beforeUpload' of the component gets the file object for the first time.

So I hope to create a file URL after the `before Upload'callback, or have a better solution, thank you.