// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license. export type CallbackWithError = (err?: Error) => void; export interface FileOptions { encoding?: string; mode?: number; flag?: string; } export function isFileOptions( fileOptions: string | FileOptions | undefined ): fileOptions is FileOptions { if (!fileOptions) return false; return ( (fileOptions as FileOptions).encoding != undefined || (fileOptions as FileOptions).flag != undefined || (fileOptions as FileOptions).mode != undefined ); }