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

Filesystem APIs.

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# readNDJSON

> Read a file as [newline-delimited JSON][ndjson].

<section class="usage">

## Usage

```javascript
var readNDJSON = require( '@stdlib/fs/read-ndjson' );
```

<a name="read-ndjson"></a>

#### readNDJSON( file\[, options], clbk )

Asynchronously reads a file as [newline-delimited JSON][ndjson].

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

readNDJSON( join( __dirname, 'examples', 'fixtures', 'file.ndjson' ), clbk );

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

The function accepts the following `options`:

-   **encoding**: file encoding.
-   **flag**: file status flag.
-   **reviver**: [JSON][json] transformation function.

The `options` parameter may also be a string specifying the file `encoding`.

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

readNDJSON( join( __dirname, 'examples', 'fixtures', 'file.ndjson' ), 'utf8', clbk );

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

#### readNDJSON.sync( file\[, options] )

Synchronously reads a file as [newline-delimited JSON][ndjson].

```javascript
var join = require( 'path' ).join;
var instanceOf = require( '@stdlib/assert/instance-of' );

var out = readNDJSON.sync( join( __dirname, 'examples', 'fixtures', 'file.ndjson' ) );
if ( instanceOf( out, Error ) ) {
    throw out;
}
console.log( out );
```

The function accepts the same `options` as [`readNDJSON()`](#read-ndjson) above.

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   If the `encoding` option is set to `utf8` and the file has a UTF-8 [byte order mark][bom] (BOM), the byte order mark is **removed** before attempting to parse as [newline-delimited JSON][ndjson].

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var join = require( 'path' ).join;
var readNDJSON = require( '@stdlib/fs/read-ndjson' );

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

// Synchronously read file contents...
var data = readNDJSON.sync( file, 'utf8' );
// returns [...]

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

// Asynchronously read file contents...
readNDJSON( file, clbk );
readNDJSON( 'beepboop', clbk );

function clbk( error, data ) {
    if ( error ) {
        if ( error.code === 'ENOENT' ) {
            console.error( 'JSON file does not exist.' );
        } else {
            throw error;
        }
    } else {
        console.log( 'Package description: %s', data[2].description );
    }
}
```

</section>

<!-- /.examples -->

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

<section class="related">

</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">

[json]: http://www.json.org/

[ndjson]: http://www.ndjson.org/

[bom]: https://en.wikipedia.org/wiki/Byte_order_mark

</section>

<!-- /.links -->