@stdlib/fs/read-dir/README.md

Filesystem APIs.

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# Read Directory

> Read the contents of a directory.

<section class="usage">

## Usage

```javascript
var readDir = require( '@stdlib/fs/read-dir' );
```

#### readDir( path, clbk )

Asynchronously reads the contents of a directory.

```javascript
readDir( __dirname, onRead );

function onRead( error, data ) {
    if ( error ) {
        console.error( error );
    } else {
        console.log( data );
        // => [...]
    }
}
```

#### readDir.sync( path )

Synchronously reads the contents of a directory.

```javascript
var out = readDir.sync( __dirname );
if ( out instanceof Error ) {
    throw out;
}
console.log( out );
// => [...]
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

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

    ```javascript
    var fs = require( 'fs' );

    var dir = '/path/to/dir';

    // Check for existence to prevent an error being thrown...
    if ( fs.existsSync( dir ) ) {
        dir = fs.readdirSync( dir );
    }
    ```

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

    ```javascript
    var readDir = require( '@stdlib/fs/read-dir' );

    var dir = '/path/to/dir';

    // Explicitly handle the error...
    dir = readDir.sync( dir );
    if ( dir instanceof Error ) {
        // You choose what to do...
        throw dir;
    }
    ```

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var readDir = require( '@stdlib/fs/read-dir' );

/* Sync */

var out = readDir.sync( __dirname );
// returns <Array>

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

out = readDir.sync( 'beepboop' );
// returns <Error>

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

/* Async */

readDir( __dirname, onRead );
readDir( 'beepboop', onRead );

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

</section>

<!-- /.examples -->

* * *

<section class="cli">

## CLI

<section class="usage">

### Usage

```text
Usage: read-dir [options] <dirpath>

Options:

  -h,    --help                Print this message.
  -V,    --version             Print the package version.
```

</section>

<!-- /.usage -->

<section class="notes">

### Notes

-   Relative paths are resolved relative to the current working directory.
-   Errors are written to `stderr`.
-   Directory contents are written to `stdout`.

</section>

<!-- /.notes -->

<section class="examples">

### Examples

```bash
$ read-dir ./../
...
...
```

</section>

<!-- /.examples -->

</section>

<!-- /.cli -->

<!-- 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/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="links">

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

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

[@stdlib/fs/exists]: https://github.com/stdlib-js/fs/tree/main/exists

[@stdlib/fs/read-file]: https://github.com/stdlib-js/fs/tree/main/read-file

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

</section>

<!-- /.links -->