Add cleanup option.

As spawned processes are not cleaned up when the main process dies
this option adds the abilitiy to kill those when the spawning process
dies.

Closes sindresorhus#51

fixtures/sub-process

@@ -0,0 +1,7 @@
+#!/usr/bin/env node
+'use strict';
+
+var m = require('../');
+
+var cp = m('forever', {cleanup: true});
+console.log(cp.pid);

index.js

@@ -8,6 +8,7 @@ var npmRunPath = require('npm-run-path');
 var isStream = require('is-stream');
 var _getStream = require('get-stream');
 var pathKey = require('path-key')();
+var onExit = require('signal-exit');
 var errname = require('./lib/errname');
 
 var TEN_MEBIBYTE = 1024 * 1024 * 10;
@@ -33,7 +34,8 @@ function handleArgs(cmd, args, opts) {
 		stripEof: true,
 		preferLocal: true,
 		encoding: 'utf8',
-		reject: true
+		reject: true,
+		cleanup: false
 	}, parsed.options);
 
 	if (opts.preferLocal) {
@@ -146,6 +148,13 @@ module.exports = function (cmd, args, opts) {
 	var maxBuffer = parsed.opts.maxBuffer;
 	var spawned = childProcess.spawn(parsed.cmd, parsed.args, parsed.opts);
 
+	var removeExitHandler;
+	if (parsed.opts.cleanup) {
+		removeExitHandler = onExit(function () {
+			spawned.kill();
+		});
+	}
+
 	var promise = Promise.all([
 		processDone(spawned),
 		getStream(spawned, 'stdout', encoding, maxBuffer),
@@ -159,6 +168,10 @@ module.exports = function (cmd, args, opts) {
 		var code = result.code;
 		var signal = result.signal;
 
+		if (removeExitHandler) {
+			removeExitHandler();
+		}
+
 		if (err || code !== 0 || signal !== null) {
 			if (!err) {
 				err = new Error('Command failed: ' + joinedCmd + '\n' + stderr + stdout);

package.json

@@ -50,12 +50,14 @@
     "npm-run-path": "^1.0.0",
     "object-assign": "^4.0.1",
     "path-key": "^1.0.0",
+    "signal-exit": "^3.0.0",
     "strip-eof": "^1.0.0"
   },
   "devDependencies": {
     "ava": "*",
     "cat-names": "^1.0.2",
     "coveralls": "^2.11.9",
+    "is-running": "^2.0.0",
     "nyc": "^6.4.0",
     "xo": "*"
   },

readme.md

@@ -11,7 +11,7 @@
 - [Improved Windows support.](https://github.com/IndigoUnited/node-cross-spawn#why)
 - Higher max buffer. 10 MB instead of 200 KB.
 - [Executes locally installed binaries by name.](#preferlocal)
-
+- [Cleans up spawned processes when the parent process dies](#cleanup)
 
 ## Install
 
@@ -138,6 +138,12 @@ Default: `true`
 
 Setting this to `false` resolves the promise with the error instead of rejecting it.
 
+#### cleanup
+
+Type: `boolean`<br>
+Default: `false`
+
+Setting this to `true` keeps track of the spawned process and `kill`s it when the parent process exits.
 
 ## License
 

test.js

@@ -3,6 +3,7 @@ import stream from 'stream';
 import childProcess from 'child_process';
 import test from 'ava';
 import getStream from 'get-stream';
+import isRunning from 'is-running';
 import m from './';
 
 process.env.PATH = path.join(__dirname, 'fixtures') + path.delimiter + process.env.PATH;
@@ -276,3 +277,24 @@ cmd.title = (message, expected) => `cmd is: ${JSON.stringify(expected)}`;
 test(cmd, ' foo bar', 'foo', 'bar');
 test(cmd, ' baz quz', 'baz', 'quz');
 test(cmd, '');
+
+async function spawnAndKill(t, signal) {
+	const cp = m('sub-process');
+	let pid;
+
+	cp.stdout.on('data', chunk => {
+		pid = parseInt(chunk.toString(), 10);
+		t.is(typeof pid, 'number');
+
+		setTimeout(function () {
+			process.kill(cp.pid, signal);
+		}, 100);
+	});
+
+	await t.throws(cp);
+	t.false(isRunning(cp.pid));
+	t.false(isRunning(pid));
+}
+
+test('cleanup - SIGINT', spawnAndKill, 'SIGINT');
+test('cleanup - SIGKILL', spawnAndKill, 'SIGTERM');