exports.spawn = function()

in src/superspawn.js [70:151]

• 54 lines of code
• 15 McCabe index (conditional complexity)

exports.spawn = function (cmd, args, opts) {
    return new Promise((resolve, reject) => {
        args = args || [];
        opts = opts || {};
        const spawnOpts = {};

        if (iswin32) {
            cmd = resolveWindowsExe(cmd);
            // If we couldn't find the file, likely we'll end up failing,
            // but for things like "del", cmd will do the trick.
            if (path.extname(cmd) !== '.exe' && cmd.indexOf(' ') !== -1) {
                // We need to use /s to ensure that spaces are parsed properly with cmd spawned content
                args = [['/s', '/c', '"' + [cmd].concat(args).map(function (a) { if (/^[^"].* .*[^"]/.test(a)) return '"' + a + '"'; return a; }).join(' ') + '"'].join(' ')];
                cmd = 'cmd';
                spawnOpts.windowsVerbatimArguments = true;
            } else if (!fs.existsSync(cmd)) {
                // We need to use /s to ensure that spaces are parsed properly with cmd spawned content
                args = ['/s', '/c', cmd].concat(args);
            }
        }

        const pipeOutput = opts.stdio === 'inherit';
        if (opts.stdio === 'ignore') {
            spawnOpts.stdio = 'ignore';
        } else if (pipeOutput) {
            spawnOpts.stdio = [process.stdin, 'pipe', process.stderr];
        } else {
            spawnOpts.stdio = [process.stdin, 'pipe', 'pipe'];
        }
        if (opts.cwd) {
            spawnOpts.cwd = opts.cwd;
        }
        if (opts.env) {
            spawnOpts.env = extend(extend({}, process.env), opts.env);
        }

        if (opts.printCommand) {
            console.log('Running command: ' + maybeQuote(cmd) + ' ' + args.map(maybeQuote).join(' '));
        }

        const child = child_process.spawn(cmd, args, spawnOpts);
        let capturedOut = '';
        let capturedErr = '';

        if (child.stdout) {
            child.stdout.setEncoding('utf8');
            child.stdout.on('data', function (data) {
                capturedOut += data;
                if (pipeOutput) {
                    process.stdout.write(data);
                }
            });
        }
        if (child.stderr) {
            child.stderr.setEncoding('utf8');
            child.stderr.on('data', function (data) {
                capturedErr += data;
            });
        }

        child.on('close', whenDone);
        child.on('error', whenDone);
        function whenDone (arg) {
            child.removeListener('close', whenDone);
            child.removeListener('error', whenDone);
            const code = typeof arg === 'number' ? arg : arg && arg.code;

            if (code === 0) {
                resolve(capturedOut.trim());
            } else {
                let errMsg = cmd + ': Command failed with exit code ' + code;
                if (capturedErr) {
                    errMsg += ' Error output:\n' + capturedErr.trim();
                }
                const err = new Error(errMsg);
                err.code = code;
                err.output = capturedOut.trim();
                reject(err);
            }
        }
    });
};