Unable get the audio file

[ShyamSMoorthy]

Hi , I am integrating the audio input in vuejs and able to perform every operations ,But unable to get the audio file.Every time it shows recorded duration as 0.(i.e) In stopCapture function
reader.onload = (evt : any) => {
console.log(evt.target.result);
};
evt.target.result always empty base 64 URL . Please suggest some workarounds to fix this issue.