Make the spawned process cancelable

index.js

@@ -8,6 +8,7 @@ const npmRunPath = require('npm-run-path');
 const isStream = require('is-stream');
 const _getStream = require('get-stream');
 const pFinally = require('p-finally');
+const PCancelable = require('p-cancelable');
 const onExit = require('signal-exit');
 const errname = require('./lib/errname');
 const stdio = require('./lib/stdio');
@@ -234,7 +235,7 @@ module.exports = (command, args, options) => {
 		}, parsed.options.timeout);
 	}
 
-	const processDone = new Promise(resolve => {
+	const processDone = new PCancelable((resolve, reject, onCancel) => {
 		spawned.on('exit', (code, signal) => {
 			cleanup();
 			resolve({code, signal});
@@ -251,6 +252,10 @@ module.exports = (command, args, options) => {
 				resolve({error});
 			});
 		}
+
+		onCancel(() => {
+			spawned.kill();
+		});
 	});
 
 	function destroy() {
@@ -311,6 +316,7 @@ module.exports = (command, args, options) => {
 	// eslint-disable-next-line promise/prefer-await-to-then
 	spawned.then = (onFulfilled, onRejected) => handlePromise().then(onFulfilled, onRejected);
 	spawned.catch = onRejected => handlePromise().catch(onRejected);
+	spawned.cancel = reason => processDone.cancel(reason);
 
 	// TOOD: Remove the `if`-guard when targeting Node.js 10
 	if (Promise.prototype.finally) {

package.json

@@ -41,6 +41,7 @@
 		"get-stream": "^4.0.0",
 		"is-stream": "^1.1.0",
 		"npm-run-path": "^2.0.0",
+		"p-cancelable": "^1.1.0",
 		"p-finally": "^1.0.0",
 		"signal-exit": "^3.0.0",
 		"strip-final-newline": "^2.0.0"

readme.md

@@ -51,6 +51,13 @@ const execa = require('execa');
 	const {stdout} = await execa.shell('echo unicorns');
 	//=> 'unicorns'
 
+	// Cancelling a spawned process
+	const spawned = execa("echo unicorns");
+	spawned.catch( error => {
+		// This would be equal to the reason provided for canceling
+		console.log(error.message);
+	}); // To handle the CancelError
+	spawned.cancel("reason for canceling");
 
 	// Catching an error
 	try {

test.js

@@ -569,3 +569,16 @@ if (Promise.prototype.finally) {
 		t.is(result.message, 'called');
 	});
 }
+
+test('the spawned process is cancelable', t => {
+	const spawned = execa('ls');
+	spawned.catch(error => {
+		if (error.message === 'reason' && error.isCanceled) {
+			return;
+		}
+
+		throw error;
+	}); // To handle the CancelError
+	spawned.cancel('reason');
+	t.true(spawned.killed);
+});