gulpfile.js

var gulp = require( 'gulp' );

// Plugins
var autoprefixer = require( 'gulp-autoprefixer' );
var cleanCSS     = require( 'gulp-clean-css' );
var rename       = require( 'gulp-rename' );
var uglifyEs     = require( 'gulp-uglify-es' ).default;
var watch        = require( 'gulp-watch' );
var zip          = require( 'gulp-zip' );

// Directories
var dir_assets = 'modules/*/assets/',
    dir_js     = dir_assets + 'js/',
    dir_css    = dir_assets + 'css/';

/**
 * TASK: styles
 */
var style_source_files = [
    dir_css + '*.css',
    '!' + dir_css + '*.min.css',
];

function styles() {
    return gulp.src( style_source_files )
        .pipe(
            rename(
                function(path) {
                    path.extname = '.min.css';
                }
            )
        )
        .pipe( autoprefixer( {cascade: false} ) )
        .pipe( cleanCSS( {compatibility: 'ie8'} ) )
        .pipe( gulp.dest( 'modules/' ) );
}

gulp.task( 'styles', styles );

/**
 * TASK: scripts
 */
var script_source_files = [
    dir_js + '*.js',
    '!' + dir_js + '*.min.js',
];

function scripts() {
    return gulp.src( script_source_files )
        .pipe(
            rename(
                function(path) {
                    path.extname = '.min.js';
                }
            )
        )
        .pipe( uglifyEs() )
        .pipe( gulp.dest( 'modules/' ) );
}

gulp.task( 'scripts', scripts );

/**
 * TASK: watch
 *
 * Keep watching for changes in directories to automate tasks
 */

function watch_changes() {
    gulp.watch( style_source_files, gulp.series( 'styles' ) );
    gulp.watch( script_source_files, gulp.series( 'scripts' ) );
}

gulp.task( 'watch', watch_changes );

/**
 * TASK: default
 *
 * Run style, script and generate a ZIP to be published
 */
var trunk_files = [
    './**/*',
    '!node_modules/**/*',
    '!vendor/**/*',
    '!tests/**/*',
    '!*',
    './index.php',
    './LICENSE.txt',
    './readme.txt',
    './woo-checkout-braspag.php'
];

function build() {
    return gulp.src(trunk_files)
        .pipe(zip('trunk.zip'))
        .pipe(gulp.dest('.'));
}

gulp.task( 'default', gulp.series( gulp.parallel( styles, scripts ), build ) );