@stdlib/fs-open NPM

Open

Open a file.

Installation

npm install @stdlib/fs-open

Usage

var open = require( '@stdlib/fs-open' );

open( path[, flags[, mode]], clbk )

Asynchronously opens a file.

var closeSync = require( '@stdlib/fs-close' ).sync;

open( __filename, onOpen );

function onOpen( error, fd ) {
    if ( error ) {
        console.error( error.message );
    } else {
        closeSync( fd );
    }
}

The function has the same default parameter values as fs.open().

open.sync( file[, flags[, mode]] )

Synchronously opens a file.

var closeSync = require( '@stdlib/fs-close' ).sync;

var fd = open.sync( __filename );
if ( fd instanceof Error ) {
    console.error( fd.message );
} else {
    closeSync( fd );
}

The function has the same default parameters as fs.openSync().

Notes

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

var fs = require( 'fs' );

var fpath = '/path/to/file.js';
var fd;

// Check for existence to prevent an error being thrown...
if ( fs.existsSync( fpath ) ) {
    fd = fs.readFileSync( fpath );
}

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

var open = require( '@stdlib/fs-open' );

var fpath = '/path/to/file.js';

// Explicitly handle the error...
var fd = open.sync( fpath );
if ( fd instanceof Error ) {
    // You choose what to do...
    console.error( fd.message );
}

Examples

var join = require( 'path' ).join;
var closeSync = require( '@stdlib/fs-close' ).sync;
var open = require( '@stdlib/fs-open' );

/* Sync */

var fd = open.sync( join( __dirname, 'package.json' ), 'r+' );
// returns <number>

if ( fd instanceof Error ) {
    console.error( fd.message );
} else {
    closeSync( fd );
}

fd = open.sync( 'beepboop' );
// returns <Error>

/* Async */

open( join( __dirname, 'package.json' ), onOpen );
open( 'beepboop', onOpen );

function onOpen( error, fd ) {
    if ( error ) {
        if ( error.code === 'ENOENT' ) {
            console.error( 'File does not exist.' );
        } else {
            console.error( error.message );
        }
    } else {
        closeSync( fd );
    }
}

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.