gulp file example

gulpfile.example.js

var gulp = require('gulp');
var cp = require('child_process');

gulp.task('default', ['build:client', 'watch'], function () {
  gulp.start('server:spawn');
});

gulp.task('watch', function () {
  gulp.watch('src/*.js', ['build:client']);
  gulp.watch('server.js', ['server:restart']);
});

gulp.task('build:client', function (cb) {
  cp.spawn('webpack', {stdio: 'inherit'})
    .on('exit', function () {
      cb();
    });
});

gulp.task('build:server', function () {
  console.log('server');
});

gulp.task('server:spawn', function () {
  spawnServer();
});

gulp.task('server:restart', function () {
  killServer();
  spawnServer();
});

var _p;

function spawnServer () {
  if (_p) {
    _p.kill();
  }

  _p = cp.spawn('node', ['server.js'], {
    stdio: 'inherit'
  });
}

function killServer () {
  if (_p) {
    _p.kill();
  }
}

process.on('exit', function () {
  killServer();
});