open

What is open?

The 'open' npm package is a simple utility to open a file, URL, or executable in the default program associated with that file type on the user's operating system. It can be used to open resources in the default browser, editor, or any other program.

What are open's main functionalities?

Open URLs in the default web browser

This feature allows you to open a URL in the user's default web browser.

const open = require('open');
open('https://www.example.com');

Open files in the default application

This feature allows you to open a file in the default application associated with its file type, such as a PDF in a PDF viewer.

const open = require('open');
open('path/to/file.pdf');

Open files with a specific application

This feature allows you to open a file with a specific application, bypassing the default application.

const open = require('open');
open('path/to/file.txt', {app: {name: 'notepad'}});

Open files with application and arguments

This feature allows you to open a file with a specific application and pass command-line arguments to the application.

const open = require('open');
open('path/to/file', {app: {name: 'app-name', arguments: ['--arg1', '--arg2']}});

Other packages similar to open

opn

The 'opn' package was the predecessor to 'open' and has since been deprecated in favor of 'open'. It offered similar functionality to open resources with the default application or a specified one.

execa

While 'execa' is more of a process execution tool than a direct alternative to 'open', it can be used to achieve similar results by running system commands to open files or URLs with specific applications.

start

The 'start' package is another alternative that can open files or URLs using the default application. It is less feature-rich compared to 'open' and is specific to Windows.

README

open

Open stuff like URLs, files, executables. Cross-platform.

This is meant to be used in command-line tools and scripts, not in the browser.

If you need this for Electron, use shell.openPath() instead.

Note: The original open package was previously deprecated in favor of this package, and we got the name, so this package is now named open instead of opn. If you're upgrading from the original open package (open@0.0.5 or lower), keep in mind that the API is different.

Why?

• Actively maintained.
• Supports app arguments.
• Safer as it uses spawn instead of exec.
• Fixes most of the open original node-open issues.
• Includes the latest xdg-open script for Linux.
• Supports WSL paths to Windows apps.

Install

$ npm install open

Usage

const open = require('open');

(async () => {
	// Opens the image in the default image viewer and waits for the opened app to quit.
	await open('unicorn.png', {wait: true});
	console.log('The image viewer app quit');

	// Opens the URL in the default browser.
	await open('https://sindresorhus.com');

	// Opens the URL in a specified browser.
	await open('https://sindresorhus.com', {app: 'firefox'});

	// Specify app arguments.
	await open('https://sindresorhus.com', {app: ['google chrome', '--incognito']});
})();

API

It uses the command open on macOS, start on Windows and xdg-open on other platforms.

open(target, options?)

Returns a promise for the spawned child process. You would normally not need to use this for anything, but it can be useful if you'd like to attach custom event listeners or perform other operations directly on the spawned process.

target

Type: string

The thing you want to open. Can be a URL, file, or executable.

Opens in the default app for the file type. For example, URLs opens in your default browser.

options

Type: object

wait

Type: boolean
Default: false

Wait for the opened app to exit before fulfilling the promise. If false it's fulfilled immediately when opening the app.

Note that it waits for the app to exit, not just for the window to close.

On Windows, you have to explicitly specify an app for it to be able to wait.

background ^{(macOS only)}

Type: boolean
Default: false

Do not bring the app to the foreground.

app

Type: string | string[]

Specify the app to open the target with, or an array with the app and app arguments.

The app name is platform dependent. Don't hard code it in reusable modules. For example, Chrome is google chrome on macOS, google-chrome on Linux and chrome on Windows.

You may also pass in the app's full path. For example on WSL, this can be /mnt/c/Program Files (x86)/Google/Chrome/Application/chrome.exe for the Windows installation of Chrome.

url

Type: boolean
Default: false

Uses URL to encode the target before executing it.
We do not recommend using it on targets that are not URLs.

Especially useful when dealing with the double-quotes on Windows caveat.

allowNonzeroExitCode

Type: boolean
Default: false

Allow the opened app to exit with nonzero exit code when the wait option is true.

We do not recommend setting this option. The convention for success is exit code zero.

Caveats

Double-quotes on Windows

TL;DR: All double-quotes are stripped from the target and do not get to your desired destination (on Windows!).

Due to specific behaviors of Window's Command Prompt (cmd.exe) regarding ampersand (&) characters breaking commands and URLs, double-quotes are now a special case.

The solution (#146) to this and other problems was to leverage the fact that cmd.exe interprets a double-quoted argument as a plain text argument just by quoting it (like Node.js already does). Unfortunately, cmd.exe can only do one of two things: handle them all OR not handle them at all. As per its own documentation:

If /C or /K is specified, then the remainder of the command line after the switch is processed as a command line, where the following logic is used to process quote (") characters:

1. If all of the following conditions are met, then quote characters on the command line are preserved:
   • no /S switch
   • exactly two quote characters
   • no special characters between the two quote characters, where special is one of: &<>()@^|
   • there are one or more whitespace characters between the two quote characters
   • the string between the two quote characters is the name of an executable file.
2. Otherwise, old behavior is to see if the first character is a quote character and if so, strip the leading character and remove the last quote character on the command line, preserving any text after the last quote character.

The option that solved all of the problems was the second one, and for additional behavior consistency we're also now using the /S switch, so we always get the second option. The caveat is that this built-in double-quotes handling ends up stripping all of them from the command line and so far we weren't able to find an escaping method that works (if you do, please feel free to contribute!).

To make this caveat somewhat less impactful (at least for URLs), check out the url option. Double-quotes will be "preserved" when using it with an URL.

Related

• open-cli - CLI for this module
• open-editor - Open files in your editor at a specific line and column

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