Read File

Read the entire contents of a file.

Installation

npm install @stdlib/fs-read-file

Usage

var readFile = require( '@stdlib/fs-read-file' );

readFile( file[, options], clbk )

Asynchronously reads the entire contents of a file.

readFile( __filename, onFile );

function onFile( error, data ) {
    if ( error ) {
        throw error;
    }
    console.log( data );
}

The function accepts the same options and has the same defaults as fs.readFile().

readFile.sync( file[, options] )

Synchronously reads the entire contents of a file.

var out = readFile.sync( __filename );
if ( out instanceof Error ) {
    throw out;
}
console.log( out );

The function accepts the same options and has the same defaults as fs.readFileSync().

Notes

• The difference between this API and fs.readFileSync() is that fs.readFileSync() will throw if an error is encountered (e.g., if given a non-existent path) and this API will return an error. Hence, the following anti-pattern

  var fs = require( 'fs' );
  
  var file = '/path/to/file.js';
  
  // Check for existence to prevent an error being thrown...
  if ( fs.existsSync( file ) ) {
      file = fs.readFileSync( file );
  }

  can be replaced by an approach which addresses existence via error handling.

  var readFile = require( '@stdlib/fs-read-file' );
  
  var file = '/path/to/file.js';
  
  // Explicitly handle the error...
  file = readFile.sync( file );
  if ( file instanceof Error ) {
      // You choose what to do...
      console.error( file.message );
  }

Examples

var readFile = require( '@stdlib/fs-read-file' );

/* Sync */

var file = readFile.sync( __filename, 'utf8' );
// returns <string>

console.log( file instanceof Error );
// => false

file = readFile.sync( 'beepboop', {
    'encoding': 'utf8'
});
// returns <Error>

console.log( file instanceof Error );
// => true

/* Async */

readFile( __filename, onFile );
readFile( 'beepboop', onFile );

function onFile( error, data ) {
    if ( error ) {
        if ( error.code === 'ENOENT' ) {
            console.error( 'File does not exist.' );
        } else {
            throw error;
        }
    } else {
        console.log( data );
    }
}

See Also

• @stdlib/fs-read-file-cli: CLI package for use as a command-line utility.
• @stdlib/fs-exists: test whether a path exists on the filesystem.
• @stdlib/fs-open: open a file.
• @stdlib/fs-read-dir: read the entire contents of a directory.
• @stdlib/fs-read-json: read a file as JSON.
• @stdlib/fs-write-file: write data to a file.

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.