collar-dev-server/gulpfile.js

const gulp = require('gulp');
const browserSync = require('browser-sync').create();

const webpack = require('gulp-webpack');

gulp.task('webpack', function() {
  return gulp.src('src/**/*.js')
    .pipe(webpack( require('./webpack.config.js') ))
    .pipe(gulp.dest('public/js/'))
    .pipe(browserSync.stream());
});

gulp.task('webpack:watch', function () {
  gulp.watch('./src/**/*.js', ['webpack']);
});

gulp.task('browser-sync', ['webpack'], function () {
  browserSync.init({
    // server: {
    //  baseDir: './public'
    // },
    proxy: {
      target: "localhost:7500", // can be [virtual host, sub-directory, localhost with port]
      ws: true // enables websockets
    }
  });

  gulp.watch('./src/**/*.js', ['webpack']);
  gulp.watch('./public/*.html').on('change', browserSync.reload);
  gulp.watch('./public/css/**/*.css').on('change', browserSync.reload);
});

gulp.task('default', ['browser-sync', 'webpack:watch']);