npm package: @stdlib/fs-write-file
Description: Write data to a file.
Author: The Stdlib Authors
Latest version: 0.2.3

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<details>
  <summary>
    About stdlib...
  </summary>
  <p>We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.</p>
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</details>

# Write File

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> Write data to a file.

<section class="installation">

## Installation

```bash
npm install @stdlib/fs-write-file
```

</section>

<section class="usage">

## Usage

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

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

Asynchronously writes `data` to a `file`.

```javascript
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`][@stdlib/buffer/ctor].

```javascript
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()`][node-fs].

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

Synchronously writes `data` to a `file`.

```javascript
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()`][node-fs].

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   The difference between this `writeFile.sync` and [`fs.writeFileSync()`][node-fs] is that [`fs.writeFileSync()`][node-fs] 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

    <!-- run-disable -->

    ```javascript
    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.

    <!-- run-disable -->

    ```javascript
    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;
    }
    ```

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
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!' );
}
```

</section>

<!-- /.examples -->



<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

## See Also

-   <span class="package-name">[`@stdlib/fs-write-file-cli`][@stdlib/fs-write-file-cli]</span><span class="delimiter">: </span><span class="description">CLI package for use as a command-line utility.</span>
-   <span class="package-name">[`@stdlib/fs-exists`][@stdlib/fs/exists]</span><span class="delimiter">: </span><span class="description">test whether a path exists on the filesystem.</span>
-   <span class="package-name">[`@stdlib/fs-read-file`][@stdlib/fs/read-file]</span><span class="delimiter">: </span><span class="description">read the entire contents of a file.</span>

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->


<section class="main-repo" >

* * *

## Notice

This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

<!-- /.stdlib -->

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<section class="links">

[@stdlib/fs-write-file-cli]: https://www.npmjs.com/package/@stdlib/fs-write-file-cli

[npm-image]: http://img.shields.io/npm/v/@stdlib/fs-write-file.svg
[npm-url]: https://npmjs.org/package/@stdlib/fs-write-file

[test-image]: https://github.com/stdlib-js/fs-write-file/actions/workflows/test.yml/badge.svg?branch=v0.2.3
[test-url]: https://github.com/stdlib-js/fs-write-file/actions/workflows/test.yml?query=branch:v0.2.3

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/fs-write-file/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/fs-write-file?branch=main

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[stdlib]: https://github.com/stdlib-js/stdlib

[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors

[cli-section]: https://github.com/stdlib-js/fs-write-file#cli
[cli-url]: https://github.com/stdlib-js/fs-write-file/tree/cli
[@stdlib/fs-write-file]: https://github.com/stdlib-js/fs-write-file/tree/main

[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

[deno-url]: https://github.com/stdlib-js/fs-write-file/tree/deno
[deno-readme]: https://github.com/stdlib-js/fs-write-file/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/fs-write-file/tree/umd
[umd-readme]: https://github.com/stdlib-js/fs-write-file/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/fs-write-file/tree/esm
[esm-readme]: https://github.com/stdlib-js/fs-write-file/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/fs-write-file/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/fs-write-file/main/LICENSE

[node-fs]: https://nodejs.org/api/fs.html

[@stdlib/buffer/ctor]: https://www.npmjs.com/package/@stdlib/buffer-ctor

[standard-stream]: https://en.wikipedia.org/wiki/Pipeline_%28Unix%29

<!-- <related-links> -->

[@stdlib/fs/exists]: https://www.npmjs.com/package/@stdlib/fs-exists

[@stdlib/fs/read-file]: https://www.npmjs.com/package/@stdlib/fs-read-file

<!-- </related-links> -->

</section>

<!-- /.links -->