Sample gulp file for node js development with auto reload

gulpfile.js

const gulp = require('gulp');
const spawn = require('child_process').spawn;
let node;

function server() {
  if (node) {
    node.kill();
  }
  node = spawn('npm', ['run', 'runserver'], {stdio: 'inherit'});
  node.on('close', function (code) {
    if (code === 8) {
      gulp.log('Error detected, waiting for changes...');
    }
  });
}

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

gulp.task('watch-server', function() {
});

const watcher = gulp.watch(['./backend/**/*.js', './backend.js']);
watcher.on('change', function() {
  console.log('server files modified')
  server();
})

gulp.task('default', gulp.series('server', 'watch-server'));

// clean up if an error goes unhandled.
process.on('exit', function() {
  if (node) {
    node.kill();
  }
});