Function checkFileExists

src/modules/OPFS.ts:62–75

(
  directoryHandle: FileSystemDirectoryHandle,
  fileName: string
)

}

async function checkFileExists(
  directoryHandle: FileSystemDirectoryHandle,
  fileName: string
): Promise<boolean> {
  try {
    await directoryHandle.getFileHandle(fileName);
    return true;
  } catch (e) {
    if (e instanceof Error && e.name === 'NotFoundError') {
      return false;
    }
    throw e;
  }
}

function addSuffixToFile(fileName: string, suffix: number): string {
  const dotIndex = fileName.lastIndexOf('.');