waveform-playlist/lib/track/loader/BlobLoader.js

import Loader from "./Loader";
export default class extends Loader {
  /*
   * Loads an audio file via a FileReader
   */
  load() {
    return new Promise((resolve, reject) => {
      if (this.src.type.match(/audio.*/) || // added for problems with Firefox mime types + ogg.
      this.src.type.match(/video\/ogg/)) {
        const fr = new FileReader();
        fr.readAsArrayBuffer(this.src);
        fr.addEventListener("progress", e => {
          super.fileProgress(e);
        });
        fr.addEventListener("load", e => {
          const decoderPromise = super.fileLoad(e);
          decoderPromise.then(audioBuffer => {
            resolve(audioBuffer);
          }).catch(reject);
        });
        fr.addEventListener("error", reject);
      } else {
        reject(Error(`Unsupported file type ${this.src.type}`));
      }
    });
  }

}