understrap/gulpfile.js

// Defining requirements
var gulp = require('gulp');
var plumber = require('gulp-plumber');
var sass = require('gulp-sass');
var watch = require('gulp-watch');
var cssnano = require('gulp-cssnano');
var rename = require('gulp-rename');
var concat = require('gulp-concat');
var uglify = require('gulp-uglify');
var merge2 = require('merge2');
var imagemin = require('gulp-imagemin');
var ignore = require('gulp-ignore');
var rimraf = require('gulp-rimraf');
var clone = require('gulp-clone');
var merge = require('gulp-merge');
var sourcemaps = require('gulp-sourcemaps');
var browserSync = require('browser-sync').create();
var del = require('del');
var cleanCSS = require('gulp-clean-css');
var gulpSequence = require('gulp-sequence');
var replace = require('gulp-replace');
var autoprefixer = require('gulp-autoprefixer');

// Configuration file to keep your code DRY
var cfg = require('./gulpconfig.json');
var paths = cfg.paths;

// Run:
// gulp sass + cssnano + rename
// Prepare the min.css for production (with 2 pipes to be sure that "theme.css" == "theme.min.css")
gulp.task('scss-for-prod', function() {
    var source =  gulp.src(paths.sass + '/*.scss')
        .pipe(plumber({
            errorHandler: function (err) {
                console.log(err);
                this.emit('end');
            }
        }))
        .pipe(sourcemaps.init({loadMaps: true}))
        .pipe(sass());

    var pipe1 = source.pipe(clone())
        .pipe(sourcemaps.write(undefined, { sourceRoot: null }))
        .pipe(gulp.dest(paths.css))
        .pipe(rename('custom-editor-style.css'))


    var pipe2 = source.pipe(clone())
        .pipe(minify-css())
        .pipe(rename({suffix: '.min'}))
        .pipe(gulp.dest(paths.css));

    return merge(pipe1, pipe2);
});


// Run:
// gulp sourcemaps + sass + reload(browserSync)
// Prepare the child-theme.css for the development environment
gulp.task('scss-for-dev', function() {
    gulp.src(paths.sass + '/*.scss')
        .pipe(plumber({
            errorHandler: function (err) {
                console.log(err);
                this.emit('end');
            }
        }))
        .pipe(sourcemaps.init({loadMaps: true}))
        .pipe(sass())
        .pipe(sourcemaps.write(undefined, { sourceRoot: null }))
        .pipe(gulp.dest(paths.css))
});

gulp.task('watch-scss', ['browser-sync'], function () {
    gulp.watch(paths.sass + '/**/*.scss', ['scss-for-dev']);
});


// Run:
// gulp sass
// Compiles SCSS files in CSS
gulp.task('sass', function () {
    var stream = gulp.src(paths.sass + '/*.scss')
        .pipe(plumber({
            errorHandler: function (err) {
                console.log(err);
                this.emit('end');
            }
        }))
        .pipe(sass())
        .pipe(autoprefixer('last 2 versions'))
        .pipe(gulp.dest(paths.css))
        .pipe(rename('custom-editor-style.css'))
    return stream;
});


// Run:
// gulp watch
// Starts watcher. Watcher runs gulp sass task on changes
gulp.task('watch', function () {
    gulp.watch(paths.sass + '/**/*.scss', ['styles']);
    gulp.watch([paths.dev + '/js/**/*.js','js/**/*.js','!js/theme.js','!js/theme.min.js'], ['scripts']);

    //Inside the watch task.
    gulp.watch('./img/**', ['imagemin'])
});

// Run:
// gulp imagemin
// Running image optimizing task
gulp.task('imagemin', function(){
    gulp.src('img/src/**')
    .pipe(imagemin())
    .pipe(gulp.dest('img'))
});


// Run:
// gulp cssnano
// Minifies CSS files
gulp.task('cssnano', function(){
  return gulp.src(paths.css + '/theme.css')
    .pipe(sourcemaps.init({loadMaps: true}))
    .pipe(plumber({
            errorHandler: function (err) {
                console.log(err);
                this.emit('end');
            }
        }))
    .pipe(rename({suffix: '.min'}))
    .pipe(cssnano({discardComments: {removeAll: true}}))
    .pipe(sourcemaps.write('./'))
    .pipe(gulp.dest(paths.css))
});

gulp.task('minify-css', function() {
  return gulp.src(paths.css + '/theme.css')
  .pipe(sourcemaps.init({loadMaps: true}))
    .pipe(cleanCSS({compatibility: '*'}))
    .pipe(plumber({
            errorHandler: function (err) {
                console.log(err);
                this.emit('end');
            }
        }))
    .pipe(rename({suffix: '.min'}))
     .pipe(sourcemaps.write('./'))
    .pipe(gulp.dest(paths.css));
});

gulp.task('cleancss', function() {
  return gulp.src(paths.css + '/*.min.css', { read: false }) // much faster
    .pipe(ignore('theme.css'))
    .pipe(rimraf());
});

gulp.task('styles', function(callback){ gulpSequence('sass', 'minify-css')(callback) });
 

// Run:
// gulp browser-sync
// Starts browser-sync task for starting the server.
gulp.task('browser-sync', function() {
    browserSync.init(cfg.browserSyncWatchFiles, cfg.browserSyncOptions);
});


// Run:
// gulp watch-bs
// Starts watcher with browser-sync. Browser-sync reloads page automatically on your browser
gulp.task('watch-bs', ['browser-sync', 'watch', 'scripts'], function () { });


// Run: 
// gulp scripts. 
// Uglifies and concat all JS files into one
gulp.task('scripts', function() {
    var scripts = [

        // Start - All BS4 stuff
        paths.dev + '/js/bootstrap4/bootstrap.js',

        // End - All BS4 stuff

        paths.dev + '/js/skip-link-focus-fix.js'
    ];
  gulp.src(scripts)
    .pipe(concat('theme.min.js'))
    .pipe(uglify())
    .pipe(gulp.dest(paths.js));

  gulp.src(scripts)
    .pipe(concat('theme.js'))
    .pipe(gulp.dest(paths.js));
});

// Deleting any file inside the /src folder
gulp.task('clean-source', function () {
  return del(['src/**/*',]);
});

// Run:
// gulp copy-assets.
// Copy all needed dependency assets files from bower_component assets to themes /js, /scss and /fonts folder. Run this task after bower install or bower update

////////////////// All Bootstrap SASS  Assets /////////////////////////
gulp.task('copy-assets', function() {

////////////////// All Bootstrap 4 Assets /////////////////////////
// Copy all JS files

  
    var stream = gulp.src(paths.node + 'bootstrap/dist/js/**/*.js')
        .pipe(gulp.dest(paths.dev + '/js/bootstrap4'));
// Copy all Bootstrap SCSS files
    gulp.src(paths.node + 'bootstrap/scss/**/*.scss')
        .pipe(gulp.dest(paths.dev + '/sass/bootstrap4'));
    return stream;

////////////////// End Bootstrap 4 Assets /////////////////////////

// Copy all Font Awesome Fonts
    var stream = gulp.src(paths.node + 'font-awesome/fonts/**/*.{ttf,woff,woff2,eof,svg}')
        .pipe(gulp.dest('./fonts'));

// Copy all Font Awesome SCSS files
    gulp.src(paths.node + 'font-awesome/scss/*.scss')
        .pipe(gulp.dest(paths.dev + '/sass/fontawesome'));

// _s SCSS files
    gulp.src(paths.node + 'undescores-for-npm/sass/media/*.scss')
        .pipe(gulp.dest(paths.dev + '/sass/underscores'));

// _s JS files into /src/js
    gulp.src(paths.node + 'undescores-for-npm/js/skip-link-focus-fix.js')
        .pipe(gulp.dest(paths.dev + '/js'));

// _s JS files into /js
    gulp.src(paths.node + 'undescores-for-npm/js/skip-link-focus-fix.js')
        .pipe(gulp.dest(paths.js + paths.vendor));

// Copy Popper JS files
        
    gulp.src(paths.node + 'popper.js/dist/umd/popper.min.js')
        .pipe(gulp.dest(paths.js + paths.vendor));
    gulp.src(paths.node + 'popper.js/dist/umd/popper.js')
        .pipe(gulp.dest(paths.js + paths.vendor));
    return stream;
});

// Deleting the files distributed by the copy-assets task
gulp.task('clean-vendor-assets', function () {
  return del([paths.dev+'/js/bootstrap4/**', paths.dev+'/sass/bootstrap4/**', './fonts/*wesome*.{ttf,woff,woff2,eof,svg}', paths.dev+'/sass/fontawesome/**', paths.dev+'/sass/underscores/**', paths.dev+'/js/skip-link-focus-fix.js', paths.js+'/**/skip-link-focus-fix.js', paths.js+'/**/popper.min.js', paths.js+'/**/popper.js', (paths.vendor!=''?(paths.js+paths.vendor+'/**'):'')]);
});

// Run
// gulp dist
// Copies the files to the /dist folder for distribution as simple theme
gulp.task('dist', ['clean-dist'], function() {
  return gulp.src(['**/*', '!'+paths.bower, '!'+paths.bower+'**', '!'+paths.node, '!'+paths.node+'**', '!'+paths.dev, '!'+paths.dev+'/**', '!'+paths.dist, '!'+paths.dist+'/**', '!'+paths.distprod, '!'+paths.distprod+'/**', '!'+paths.sass, '!'+paths.sass+'/**', '!readme.txt', '!readme.md', '!package.json', '!gulpfile.js', '!CHANGELOG.md', '!.travis.yml', '!jshintignore',  '!codesniffer.ruleset.xml',  '*'])
    .pipe(replace('/js/jquery.slim.min.js', '/js'+paths.vendor+'/jquery.slim.min.js'))
    .pipe(replace('/js/popper.min.js', '/js'+paths.vendor+'/popper.min.js'))
    .pipe(replace('/js/skip-link-focus-fix.js', '/js'+paths.vendor+'/skip-link-focus-fix.js'))
    .pipe(gulp.dest(paths.dist));
});

// Deleting any file inside the /dist folder
gulp.task('clean-dist', function () {
  return del([paths.dist + '/**',]);
});

// Run
// gulp dist-product
// Copies the files to the /dist-prod folder for distribution as theme with all assets
gulp.task('dist-product', ['clean-dist-product'], function() {
  return gulp.src(['**/*', '!'+paths.bower, '!'+paths.bower+'/**', '!'+paths.node, '!'+paths.node+'/**', '!'+paths.dist, '!'+paths.dist+'/**', '!'+paths.distprod, '!'+paths.distprod+'/**', '*'])
    .pipe(gulp.dest(paths.distprod))
});

// Deleting any file inside the /dist-product folder
gulp.task('clean-dist-product', function () {
  return del([paths.distprod + '/**',]);
});