export enum fileReaderType {
  text = "text",
  dataURL = "dataURL",
}

/**
 * Read a file using the FileReader API, either as a plain text string or as a DataURL string.
 * Returns a promise which will resolve with the file contents as a string or reject with a DOMException.
 *
 * @param {File} fileHandle - File object to read
 * @param {fileReaderType} type - How to read it
 */
export function readFile(fileHandle: File, type: fileReaderType) {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();

    reader.onload = () => resolve(reader.result);
    reader.onerror = () => reject(reader.error);

    switch (type) {
      case fileReaderType.text:
        reader.readAsText(fileHandle);
        break;
      case fileReaderType.dataURL:
        reader.readAsDataURL(fileHandle);
        break;
      default:
        reject("unknown type");
    }
  });
}