Failed to execute 'readAsText' on 'FileReader': parameter 1 is not of type 'Blob'

I am trying to read a user uploaded xml file in angular. Below is my code:

Component.ts:

convertFileToString(event){    this.uploadXML=event.target.files[0];    let fileReader = new FileReader();    fileReader.onload = (event) =>{this.finalUploadedXML=fileReader.result as String}    fileReader.readAsText(this.uploadXML);    console.log("The contents are:")    console.log(this.finalUploadedXML);  }

index.html

<input type="file" id="uploadInput" (change)="convertFileToString($event)" hidden>

But when i run this code, it gives me the following error:

Failed to execute 'readAsText' on 'FileReader': parameter 1 is not of type 'Blob'

I also modified the readAsText(this.uploadXML) to readAsText(this.uploadXML.asInstanceOf[Blob]) but it seems that asInstanceOf is not a known property of File type. So i tried changing the type of uploadXML from File to Blob and the error still persists. What should i do?