尝试在Windows上使用Gulp和Babel来分叉Node.js进程

Question

My application is built with isomorphic JavaScript, and I'm using a Gulp task to run a Node.js server on a new instance, then listening to files change to make a server restart and a browser reload (using Browsersync ).

I want to use Babel to write my server-side code in ECMAScript 6, as well as my client-side code. I want to avoid the Babel polyfill and use node_modules/.bin/babel-core.cmd server.js command instead, but child_process.fork() allows only an executable:

let child = cp.fork('server.js', [], {
  execPath: path.normalize('node_modules/.bin/babel-node.cmd'),
  env: _.assign({NODE_ENV: 'development'}, process.env)
});

This script doesn't work, and as intended, throws the following error:

child_process.js:588
  p.open(fd);
    ^
Error: EINVAL, invalid argument
    at Error (native)
    at Object.exports._forkChild (child_process.js:588:5)
    at Function.startup.processChannel (node.js:704:10)
    at startup (node.js:59:15)
    at node.js:814:3

I want to use child_process.fork() to this case. child_process.spawn() doesn't work here because there is not a direct communication between the two Node.js processes, indeed. And I'm listening from events to performs actions:

// server.js

server.listen(port, function() {
  if (process.send) {
    process.send('online');
  } else {
    ...
  }
});

// gulpfile.babel.js

child.on('message', (message) => {
  if (message.match(/^online$/)) {
    if (browserSyncServer) {
      browserSyncServer.reload();
    }

    if (!started) {
      started = true;

      gulp.watch(config.serverScripts, () => {
        plugins.util.log('Restarting development server.');

        server.kill('SIGTERM');
        server = startup();
      });

      cb();
    }
  }
});

Any workaround with this? Or I'm forced to use the Babel polyfill directly on my server-side code?

Answer 1

You can change the command that it uses to spawn the node process with the execPath option.

For example, if I want to spawn a node server with babel-node instead of node , I can type:

process.fork('/path/to/server.js', { execPath: "babel-node" }, function(error, stdout, stderr) {
  console.log('stdout: ' + stdout);
  console.log('stderr: ' + stderr);

  if (error !== null) {
    console.log('exec error: ' + error);
  }
});

Answer 2

I had this problem was well. With this issue I open on mocha I could solve the problem.

Running babel-node node_modules/mocha/bin/_mocha test.js applies by default the compiler to the child process and there is no need to set the execPath .

PS: Once you run the mocha with babel-node there is no need to pass --require or --compilers .