Splitting up Gulp tasks in separate files

gulpfile.js

// gulpfile.js

var gulp = require('gulp');
var requireDir = require('require-dir');
var tasks = requireDir('./tasks');

gulp.task('sass', tasks.sass);
gulp.task('serve:dev', tasks.serve.dev);
gulp.task('serve:dist', tasks.serve.dist);

gulp.task('default', ['sass', 'serve:dev']);

sass.js

// tasks/sass.js

var gulp = require('gulp');
var sass = require('gulp-sass');

module.exports = function () {
  return gulp.src('./scss/app.scss')
    .pipe(sass())
    .pipe(gulp.dest('./css'));
};

serve.js

// tasks/serve.js

var browserSync = require('browser-sync');

module.exports = {
  dev: function () {
    browserSync({
      port: 1337,
      notify: false,
      server: {
        baseDir: ['app', './']
      }
    });
  },
  dist: function () {
    browserSync({
      port: 1338,
      notify: false,
      server: {
        baseDir: ['dist', './']
      }
    });
  }
};