Variable readFile

Type declaration

• • (
        path: PathLike | FileHandle,
        options?: null | { encoding?: null; flag?: OpenMode } & Abortable,
    ): Promise<NonSharedBuffer>

  • 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);
    }
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    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);
    }
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    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.

    Parameters

    • path: PathLike | FileHandle

      filename or FileHandle
    • Optionaloptions: null | { encoding?: null; flag?: OpenMode } & Abortable

    Returns Promise<NonSharedBuffer>

    Fulfills with the contents of the file.

    Since

    v10.0.0

  • (
        path: PathLike | FileHandle,
        options:
            | { encoding: BufferEncoding; flag?: OpenMode | undefined } & Abortable
            | BufferEncoding,
    ): Promise<string>

  • Asynchronously reads the entire contents of a file.

    Parameters

    • path: PathLike | FileHandle

      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.
    • options:
          | { encoding: BufferEncoding; flag?: OpenMode | undefined } & Abortable
          | BufferEncoding

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

    Returns Promise<string>
  • (
        path: PathLike | FileHandle,
        options?:
            | null
            | BufferEncoding
            | ObjectEncodingOptions & Abortable & { flag?: OpenMode | undefined },
    ): Promise<string | NonSharedBuffer>

  • Asynchronously reads the entire contents of a file.

    Parameters

    • path: PathLike | FileHandle

      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.
    • Optionaloptions:
          | null
          | BufferEncoding
          | ObjectEncodingOptions & Abortable & { flag?: OpenMode | undefined }

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

    Returns Promise<string | NonSharedBuffer>