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  • License Apache-2.0

Write data to a file.

Package Exports

  • @stdlib/fs-write-file

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@stdlib/fs-write-file) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Write File

NPM version Build Status Coverage Status dependencies

Write data to a file.

Installation

npm install @stdlib/fs-write-file

Usage

var writeFile = require( '@stdlib/fs-write-file' );

writeFile( file, data[, options], clbk )

Asynchronously write data to a file.

var join = require( 'path' ).join;

var fpath = join( __dirname, 'examples', 'fixtures', 'file.txt' );

writeFile( fpath, 'beep boop\n', onWrite );

function onWrite( error ) {
    if ( error ) {
        throw error;
    }
}

The data argument may be either a string or a Buffer.

var join = require( 'path' ).join;
var string2buffer = require( '@stdlib/buffer-from-string' );

var fpath = join( __dirname, 'examples', 'fixtures', 'file.txt' );

writeFile( fpath, string2buffer( 'beep boop\n' ), onWrite );

function onWrite( error ) {
    if ( error ) {
        throw error;
    }
}

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

writeFile.sync( file, data[, options] )

Synchronously writes data to a file.

var join = require( 'path' ).join;

var fpath = join( __dirname, 'examples', 'fixtures', 'file.txt' );

var err = writeFile.sync( fpath, 'beep boop\n' );
if ( err instanceof Error ) {
    throw err;
}

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

Notes

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

    var fs = require( 'fs' );

// Check for directory path existence to prevent an error being thrown...
if ( fs.existsSync( '/path/to' ) ) {
    fs.writeFileSync( '/path/to/file.txt', 'beep boop\n' );
}

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

    var writeFile = require( '@stdlib/fs-write-file' );

// Explicitly handle the error...
var err = writeFile.sync( '/path/to/file.txt', 'beep boop\n' );
if ( err instanceof Error ) {
    // You choose what to do...
    throw err;
}

Examples

var join = require( 'path' ).join;
var writeFile = require( '@stdlib/fs-write-file' );

var fpath = join( __dirname, 'examples', 'fixtures', 'file.txt' );

// Synchronously write data to a file:
var err = writeFile.sync( fpath, 'beep boop\n', 'utf8' );
// returns null

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

// Asynchronously write data to a file:
writeFile( fpath, 'beep boop\n', onWrite );

function onWrite( error ) {
    if ( error ) {
        console.error( 'Error: %s', error.message );
    }
    console.log( 'Success!' );
}

CLI

Installation

To use the module as a general utility, install the module globally

npm install -g @stdlib/fs-write-file

Usage

Usage: write-file [options] <filepath>

Options:

  -h,    --help                Print this message.
  -V,    --version             Print the package version.
  --enc, --encoding encoding   Encoding. Default: 'utf8'.
         --flag flag           Flag. Default: 'r'.
         --mode mode           Mode. Default: 0o666.

Notes

  • Relative output file paths are resolved relative to the current working directory.
  • Errors are written to stderr.
  • File contents should be provided over stdin as part of a standard stream pipeline.

Examples

$ printf 'beep boop\n' | write-file ./examples/fixtures/file.txt

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.

License

See LICENSE.

Copyright © 2016-2021. The Stdlib Authors.