Node.js child_process examples

Node.js child_process examples.js

'use strict';

const child_process = require('child_process');
const execCallback = (resolve, reject) => {
	return (error, stdout, stderr) => {
		stdout && console.log(stdout);
		stderr && console.log(stderr);
		error ? reject(new Error(error)) : resolve();
	};
};
const spawnForkCallback = (resolve, reject) => {
	return (code, signal) => {
		console.log(`Exited with code: ${code}, signal: ${signal}\n`);
		code ? reject(new Error(code)) : resolve();
	};
};

const file1 = './file1.sh';
const file2 = 'file2.js'

Promise.resolve()
.then(() => new Promise((resolve, reject) => {
	const cmd = `echo 'echo "Hello from ${file1}"' > ${file1}; chmod +x ${file1}; echo '${file1} writed';
echo 'console.log("Hello from ${file2}");' > ${file2}; echo '${file2} writed'
`;
	console.log(`We can execute arbitrary command(s) in one string via exec, for example:\n${cmd}`);
	child_process.exec(cmd, execCallback(resolve, reject));
}))
.then(() => new Promise((resolve, reject) => {
	console.log(`But it's not work with execFile:`);
	child_process.execFile(
		file1, // or you can try here `${file1}; echo 'hi'`, failed silently
		[
			';',
			`echo 'hi'`
		],
		execCallback(resolve, reject)
	);
}))
.then(() => new Promise((resolve, reject) => {
	console.log(`And not work with spawn:`);
	child_process.spawn(
		file1, // or you can try here `${file1}; echo 'hi'`, will raise error ENOENT
		[
			' > not_be_writed',
		],
		{stdio: 'inherit'}
	).on('exit', spawnForkCallback(resolve, reject));
}))
.then(() => new Promise((resolve, reject) => {
	console.log(`And not work with fork:`);
	child_process.fork(
		file2, // or you can try here `${file2}; echo 'hi'`, will raise error "Cannot find module..."
		[
			' > not_writed_too'
		]
	).on('exit', spawnForkCallback(resolve, reject));
}));