FreadFile
Bun

function

fs.promises.readFile

function readFile(
options?: null | { encoding: null; flag: OpenMode } & Abortable
): Promise<Buffer<ArrayBufferLike>>;

Asynchronously reads the entire contents of a file.

If no encoding is specified (using options.encoding), the data is returned as a Buffer object. Otherwise, the data will be a string.

If options is a string, then it specifies the encoding.

When the path is a directory, the behavior of fsPromises.readFile() is platform-specific. On macOS, Linux, and Windows, the promise will be rejected with an error. On FreeBSD, a representation of the directory's contents will be returned.

An example of reading a package.json file located in the same directory of the running code:

import { readFile } from 'node:fs/promises';
try {
  const filePath = new URL('./package.json', import.meta.url);
  const contents = await readFile(filePath, { encoding: 'utf8' });
  console.log(contents);
} catch (err) {
  console.error(err.message);
}

It is possible to abort an ongoing readFile using an AbortSignal. If a request is aborted the promise returned is rejected with an AbortError:

import { readFile } from 'node:fs/promises';

try {
  const controller = new AbortController();
  const { signal } = controller;
  const promise = readFile(fileName, { signal });

  // Abort the request before the promise settles.
  controller.abort();

  await promise;
} catch (err) {
  // When a request is aborted - err is an AbortError
  console.error(err);
}

Aborting an ongoing request does not abort individual operating system requests but rather the internal buffering fs.readFile performs.

Any specified FileHandle has to support reading.

@param path

filename or FileHandle

@returns

Fulfills with the contents of the file.

function readFile(
options: BufferEncoding | { encoding: BufferEncoding; flag: unknown } & Abortable
): Promise<string>;

Asynchronously reads the entire contents of a file.

@param path

A path to a file. If a URL is provided, it must use the file: protocol. If a FileHandle is provided, the underlying file will not be closed automatically.

@param options

An object that may contain an optional flag. If a flag is not provided, it defaults to 'r'.

function readFile(
options?: null | BufferEncoding | ObjectEncodingOptions & Abortable & { flag: unknown }
): Promise<string | Buffer<ArrayBufferLike>>;

Asynchronously reads the entire contents of a file.

@param path

A path to a file. If a URL is provided, it must use the file: protocol. If a FileHandle is provided, the underlying file will not be closed automatically.

@param options

An object that may contain an optional flag. If a flag is not provided, it defaults to 'r'.