Better-spawn NPM

Better spawn

Because child_process.exec lacks features and child_process.spawn acts weird, better-spawn was made.

It is a very simple wrapper around child_process.spawn to make opening and closing work consistently in linux and windows.
Used by script-runner

Install

npm install better-spawn

Breaking changes @1

child.closed and child.killed are now promises. The boolean states are now available at child.isClosed and child.isKilled.

Usage

spawn = require('better-spawn')
child = spawn('node', options)

Options

Name	type	default	description
cwd	String	process.cwd	current working directory
env	Object	process.env	environment variables
env.PATH	String	process.env.PATH + ./node_modules/.bin	used to resolve commands
stdio	See documentation	`["pipe","inherit","inherit"]`	to control output
noOut	Boolean	`null`	sets `stdio[1] = "pipe"`
noErr	Boolean	`null`	sets `stdio[2] = "pipe"`
windowsVerbatimArguments	Boolean	isWindows	to support windows
detach	Boolean	!isWindows	to support killing on unix
Promise	Function	global.Promise	supply your own Promise lib

Props

Name	type	description
cmd	String	cmd called
isKilled	Boolean	is child process killed
isClosed	Boolean	is child process closed
killed	Promise	fulfilled when child process killed
closed	Promise	fulfilled when child process closed
close	Function	call to kill child process

Examples

// pipe to shell without losing color
child = spawn('node')
// suppress normal output, but maintain err output
child = spawn('node',{noOut:true})
// set empty env (default in node)
child = spawn('node',{env: {PATH:""}})

Compare to other solutions

child_process.exec, spawns in shell but output has to be piped - color information will be lost.
child_process.spawn, doesn't spawn in shell, so it has to be done by hand (differs in linux and windows) Main problem is, sh won't kill its children by child.kill(), see: node#2098
cross-spawn-async a wrapper for child_process.spawn to support windows quirks like PATHEXT or shebangs not working
execa a wrapper for cross-spawn-async which adds the shell logic, to behave like child_process.exec, adds promises, modifies PATH