nodejs spawn command with string not array?

Question

I'm working on spawn on nodejs. previously I was using exec but exec has no compatibility in stdout (or stderr) steaming. now, I have a disability about spawn. It seems whereas exec accepted quoted string command, spawn does not accepted that one, just array format.

so following exec script is working correctly but another one which uses spawn will be error, due to string formatted command not array.

const exec = require('child_process').exec;

exec(` echo foo bar `, (error, stdout, stderr) => {
  if ( error ){ console.log(error) }
  if ( stdout ){ console.log(stdout) }
  if ( stderr ){ console.log(stderr) }
});

const { spawn } = require('child_process');

command = spawn('echo foo bar');

command.stdout.on('data', function (data) {
  console.log(data.toString());
});

command.stderr.on('data', function (data) {
  console.log( data.toString());
});

command.on('exit', function (code) {
  console.log( code.toString());
});

I have a lot of command line script which is what I want to spawn on nodejs, and all of them are complicated, something like following one. that's why I want to use string format for specify command rather than array. Any idea?

exec(' bash -ic "expecto \\"sudo bash -ic \\\\\\"rd ; backup_important_batch\\\\\\"\\" $PASSWORD" ', (error, stdout, stderr) => {
    if ( error ){ console.log(error) }
    if ( stdout ){ console.log(stdout) }
    if ( stderr ){ console.log(stderr) }
});

Answer 1

You can't split on spaces because many command line args may include strings like ./foo.js --bar "Hello Baz", splitting on the string will incorrectly give you "Hello Baz" as arguments.

Use a library like https://www.npmjs.com/package/string-argv to convert the string into arguments that you can pass the string to, get an array result and build your spawn() call.

Edit: Here's an example:

const { spawn } = require('child_process');
const { parseArgsStringToArgv } = require('string-argv');

async function run(command) {
    return new Promise( resolve => {
        let args = parseArgsStringToArgv(command);
        let cmd = args.shift();

        console.log(cmd, args);

        let step = spawn(cmd, args);

        step.stdout.pipe(process.stdout);
        step.stderr.pipe(process.stderr);

        step.on('close', (code) => {
           resolve(code);
        });
    });
}

let name = 'Baz';
let exitCode = await run(`echo "Hello ${name}"`);