Gulp file to compile JS/CSS for htmlwidgets

gulpfile.js

var gulp = require('gulp');
var concat = require('gulp-concat');
var uglify = require('gulp-uglify');
var uglifycss = require('gulp-uglifycss');
var mainBowerFiles = require('main-bower-files');
var gulpFilter = require('gulp-filter');

gulp.task('default', function() {
  var jsFilter = gulpFilter('**/*.js');
  var cssFilter = gulpFilter('**/*.css');

  gulp.src(mainBowerFiles())
    .pipe(jsFilter)
    .pipe(concat('all.js'))
    .pipe(uglify())
    .pipe(gulp.dest('dist'));

  gulp.src(mainBowerFiles())
    .pipe(cssFilter)
    .pipe(concat('all.css'))
    .pipe(uglifycss())
    .pipe(gulp.dest('dist'));
});