https://github.com/stdlib-js/fs-append-file
Append data to a file.
https://github.com/stdlib-js/fs-append-file
append appendfile appendfilesync appends async file filesystem fs javascript node node-js nodejs open path stdlib sync
Last synced: 10 months ago
JSON representation
Append data to a file.
- Host: GitHub
- URL: https://github.com/stdlib-js/fs-append-file
- Owner: stdlib-js
- License: apache-2.0
- Created: 2024-05-18T01:14:26.000Z (almost 2 years ago)
- Default Branch: main
- Last Pushed: 2025-02-24T03:14:27.000Z (about 1 year ago)
- Last Synced: 2025-04-22T10:10:06.252Z (10 months ago)
- Topics: append, appendfile, appendfilesync, appends, async, file, filesystem, fs, javascript, node, node-js, nodejs, open, path, stdlib, sync
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 184 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
Awesome Lists containing this project
README
About stdlib...
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The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.
When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.
To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
# Append File
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Append data to a file.
## Installation
```bash
npm install @stdlib/fs-append-file
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
- To use as a general utility for the command line, install the corresponding [CLI package][cli-section] globally.
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var appendFile = require( '@stdlib/fs-append-file' );
```
#### appendFile( file, data\[, options], clbk )
Asynchronously appends `data` to a `file`.
```javascript
var join = require( 'path' ).join;
var fpath = join( __dirname, 'examples', 'fixtures', 'file.txt' );
appendFile( fpath, 'beep boop\n', onAppend );
function onAppend( error ) {
if ( error ) {
console.log( error instanceof Error );
// => false
}
}
```
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' );
appendFile( fpath, string2buffer( 'beep boop\n' ), onAppend );
function onAppend( error ) {
if ( error ) {
console.log( error instanceof Error );
// => false
}
}
```
The function accepts the same `options` and has the same defaults as [`fs.appendFile()`][node-fs].
#### appendFile.sync( file, data\[, options] )
Synchronously appends `data` to a `file`.
```javascript
var join = require( 'path' ).join;
var fpath = join( __dirname, 'examples', 'fixtures', 'file.txt' );
var err = appendFile.sync( fpath, 'beep boop\n' );
if ( err instanceof Error ) {
throw err;
}
```
The function accepts the same `options` and has the same defaults as [`fs.appendFileSync()`][node-fs].
## Notes
- The difference between this `appendFile.sync` and [`fs.appendFileSync()`][node-fs] is that [`fs.appendFileSync()`][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
```javascript
var fs = require( 'fs' );
// Check for directory path existence to prevent an error being thrown...
if ( fs.existsSync( '/path/to' ) ) {
fs.appendFileSync( '/path/to/file.txt', 'beep boop\n' );
}
```
can be replaced by an approach which addresses existence via `error` handling.
```javascript
var appendFile = require( '@stdlib/fs-append-file' );
// Explicitly handle the error...
var err = appendFile.sync( '/path/to/file.txt', 'boop beep\n' );
if ( err instanceof Error ) {
// You choose what to do...
throw err;
}
```
## Examples
```javascript
var join = require( 'path' ).join;
var appendFile = require( '@stdlib/fs-append-file' );
var fpath = join( __dirname, 'examples', 'fixtures', 'file.txt' );
// Synchronously append data to a file:
var error = appendFile.sync( fpath, 'beep boop\n', 'utf8' );
// Function successfully executes and returns null
console.log( error instanceof Error );
// => false
// Asynchronously append data to a file:
appendFile( fpath, 'beep boop\n', onAppend );
function onAppend( error ) {
if ( error ) {
console.error( 'Error: %s', error.message );
}
console.log( 'Success!!!' );
}
```
* * *
## CLI
## Installation
To use as a general utility, install the CLI package globally
```bash
npm install -g @stdlib/fs-append-file-cli
```
### Usage
```text
Usage: append-file [options]
Options:
-h, --help Print this message.
-V, --version Print the package version.
--enc, --encoding encoding Encoding. Default: 'utf8'.
--flag flag Flag. Default: 'a'.
--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][standard-stream] pipeline.
### Examples
```bash
$ printf 'beep boop\n' | append-file ./examples/fixtures/file.txt
```
* * *
## 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 © 2016-2025. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/fs-append-file.svg
[npm-url]: https://npmjs.org/package/@stdlib/fs-append-file
[test-image]: https://github.com/stdlib-js/fs-append-file/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/fs-append-file/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/fs-append-file/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/fs-append-file?branch=main
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im
[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-append-file#cli
[cli-url]: https://github.com/stdlib-js/fs-append-file/tree/cli
[@stdlib/fs-append-file]: https://github.com/stdlib-js/fs-append-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-append-file/tree/deno
[deno-readme]: https://github.com/stdlib-js/fs-append-file/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/fs-append-file/tree/umd
[umd-readme]: https://github.com/stdlib-js/fs-append-file/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/fs-append-file/tree/esm
[esm-readme]: https://github.com/stdlib-js/fs-append-file/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/fs-append-file/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/fs-append-file/main/LICENSE
[node-fs]: https://nodejs.org/api/fs.html
[@stdlib/buffer/ctor]: https://github.com/stdlib-js/buffer-ctor
[standard-stream]: https://en.wikipedia.org/wiki/Pipeline_%28Unix%29