From http://blog.rangle.io/angular-gulp-bestpractices/

gulp-serve.js

function browserSyncInit(baseDir, files) {  
  browserSync.instance = browserSync.init(files, {
    startPath: '/', server: { baseDir: baseDir }
  });
}

// starts a development server
// runs preprocessor tasks before, 
// and serves the src and .tmp folders
gulp.task(  
    'serve', 
    ['typescript', 'jade', 'sass', 'inject' ], 
    function () {
  browserSyncInit([
    paths.tmp
    paths.src
  ], [
    paths.tmp + '/**/*.css',
    paths.tmp + '/**/*.js',
    paths.tmp + '/**/*.html'
  ]);
});

// starts a production server
// runs the build task before, 
// and serves the dist folder
gulp.task('serve:dist', ['build'], function () {  
  browserSyncInit(paths.dist);
});