Error using async and await with filereader

Needed to leverage reader to convert blob to base64, prefer to use async-await syntax so I chose to extract reader logic into helper like this:

//* Convert resBlob to base64
export const blobToData = (blob: Blob) => {
  return new Promise((resolve) => {
    const reader = new FileReader()
    reader.onloadend = () => resolve(reader.result)
    reader.readAsDataURL(blob)
  })
}

and calling it using await in main code:

//* Convert resBlob to dataUrl and resolve
const resData = await blobToData(resBlob)

Use the new read methods on the blob itself

/** @type {Event} evt */
async readFile (evt) {
  const [file] = evt.target.files
  if (!file) return
  const data = await file.text()
  return this.processFileContent(data)
}

Alternative:

evt.target.files[0]?.text().then(this.processFileContent)