ngx-uploader - Passing JSON data Object to uploadInput data, returning [object Object]

I am using ngx-uploader and with the data section inside the uploadInput, I pass additional data:

startUpload(): void {
    const event: UploadInput = {
      type: 'uploadAll',
      url: this.uploadUrl,
      method: 'post',
      data: this.data,
      headers: { 'Authorization': 'Token ' + this.userToken }
    };

    this.uploadInput.emit(event);
  }

The problem is that the data I am passing looks like this

this.data = {
    myData: {
       isThereData: true
    }
}

When reading the res.body inside my express, my data is returned as [object Object].

router.post('/path', upload.any(), (req, res, next) => {
    console.log(req.body) // logs [object, Object]
})

I can stringify the data before sending it to express, but then I need to pass the data content type along with the data from ngx-uploader, which I am unsure how to do, or if it is even possible.

I know I cannot pass an object because of the UploadInput:

export interface UploadInput {
    ...
    data?: {
        [key: string]: string | Blob;
    };
    ...
}

Is there another way to go about this?

from ngx-uploader - Passing JSON data Object to uploadInput data, returning [object Object]