gulpfile.js

//jshint node: true
/*
 * Build project assets for development and production
 *
 * Installation (Node Package Manager):
 * > npm install --global gulp-cli
 * > npm install
 *
 * Usage (GulpJS):
 * > gulp styles  [--production][--src={filepath/filename.scss} [--dest={path/dirname}]]
 * > gulp scripts [--production][--src={filepath/filename.js} [--dest={path/dirname}]]
 * > gulp upbuild [--production]
 * > gulp watch
 */
"use strict";
const pkg = require('./package.json');
const args = require('yargs').argv;
const gulp = require('gulp');
const $ = require('gulp-load-plugins')({
    pattern: ['*'],
    scope: ['devDependencies']
});

gulp.task('default', ['styles', 'scripts']);

gulp.task('styles', function(cb){
const
    srcFiles = args.src || pkg.paths.root + pkg.paths.assets + pkg.paths.src.styles + pkg.paths.ext.styles,
    destDir = args.dest || pkg.paths.root + pkg.paths.assets + pkg.paths.dest.styles;
    $.pump([gulp.src(srcFiles),
        $.sourcemaps.init(),
        $.sass({
            errLogToConsole: true,
            outputStyle: 'nested',
            //sourceComments: true,
            sourceMapEmbed: false,
            includePaths: pkg.paths.include.sass
        }),
        $.postcss([ require('autoprefixer')({
            //map: true,
            overrideBrowserslist: pkg.browserslist,
            cascade: false
        }) ]),
        $.sourcemaps.write('./', {
            includeContent: false,
            sourceRoot: pkg.paths.sourcemap.root
        }),
        gulp.dest(destDir),
        $.if(args.production, $.ignore.exclude('*.map')),
        $.size({showFiles: true, showTotal: false}),
        $.if(args.production, $.rename({suffix: '.min'})),
        $.if(args.production, $.postcss([ require('postcss-csso')({
             restructure: true
         }) ])),
        $.if(args.production, gulp.dest(destDir)),
        $.if(args.production, $.size({showFiles: true, showTotal: false}))
    ], cb);
});

gulp.task('scripts', function(cb){
const
    srcFiles = args.src || pkg.paths.root + pkg.paths.assets + pkg.paths.src.scripts + pkg.paths.ext.scripts,
    destDir = args.dest || pkg.paths.root + pkg.paths.assets + pkg.paths.dest.scripts;
    $.pump([gulp.src(srcFiles),
        $.include({hardFail: true, includePaths: [pkg.paths.root + pkg.paths.assets].concat(pkg.paths.include.js)}),
        gulp.dest(destDir),
        $.size({showFiles: true, showTotal: false}),
        $.if(args.production, $.rename(function(fullname){
            fullname.extname = '.min.js';
        })),
        $.if(args.production, $.uglify({output: {comments: '/^!/'}})),
        $.if(args.production, gulp.dest(destDir)),
        $.if(args.production, $.size({showFiles: true, showTotal: false}))
    ], cb);
});

gulp.task('upbuild', ['styles', 'scripts'], function(cb){
const
    fs = require('fs'),
    srcFile = args.src || pkg.paths.root + 'fields.yaml';
    if (fs.existsSync(srcFile)) {
        let obyaml = $.jsYaml.safeLoad(fs.readFileSync(srcFile, 'utf8'), {json: true});
        obyaml.fields.version.default++;
        fs.writeFileSync(srcFile, $.jsYaml.dump(obyaml, {indent: 4}));
    }
});

gulp.task('watch', function(){
    gulp.watch( [pkg.paths.root + pkg.paths.assets + pkg.paths.src.styles + pkg.paths.ext.styles], ['styles'] );
    gulp.watch( [pkg.paths.root + pkg.paths.assets + pkg.paths.src.scripts + pkg.paths.ext.scripts], ['scripts'] );
});