export class Decoder {
  public static decode(blob: Blob | File, actx: AudioContext): Promise<AudioBuffer> {
    return new Promise<AudioBuffer>((resolve, reject) => {
      const reader = new FileReader;
      reader.onloadend = () => {
        actx.decodeAudioData(reader.result).then(resolve, reject);
      };
      reader.onerror = reject;
      reader.onabort = reject;
      reader.readAsArrayBuffer(blob);
    });
  }
}