Express Gulp File

gulpfile.js

var gulp = require('gulp');
var exec = require('child_process').exec;
var sass = require('gulp-sass');
var nodemon = require('gulp-nodemon');
var browserSync = require('browser-sync').create();

var reload = browserSync.reload;

gulp.task('default', ['sass', 'browser-sync'], function() {
  gulp.watch("public/scss/*.scss", ['sass'], reload);
  gulp.watch(["views/**/*.pug", "./*.js"], reload);
});

// SASS Compiler
gulp.task('sass', function() {
  gulp.src('./public/scss/*.scss')
    .pipe(sass().on('error', sass.logError))
    .pipe(gulp.dest('./public/css/'))
    .pipe(reload({
      stream: true
    }));
});

//BrowserSync
gulp.task('browser-sync', ['nodemon'], function() {
  browserSync.init(null, {
    proxy: "http://localhost:8080",
    port: 3000,
    reloadDelay: 1000
  });

});


gulp.task('nodemon', function (cb) {
  var called = false;
  return nodemon({
    script: 'app.js',
    ignore: [
      'gulpfile.js',
      'node_modules/'
    ]
  })
  .on('start', function () {
    if (!called) {
      called = true;
      cb();
    }
  })
  .on('restart', function () {
    setTimeout(function () {
      reload({ stream: false });
    }, 1000);
  });
});

Reference : https://gist.github.com/dstroot/22525ae6e26109d3fc9d