kunagpal/express-boilerplate

#!/usr/bin/env node

/**
 * @file Minifies static assets in the public folder.
 */

var fs = require('fs'),
    path = require('path'),

    async = require('async'),
    uglifyJs = require('uglify-js'),
    CleanCSS = require('clean-css'),

    cleanCss = new CleanCSS(),

    TARGET_DIR = path.join('public', 'min'),
    SCRIPTS = path.join(__dirname, '..', '..', 'public', 'javascripts'),
    STYLES = path.relative(process.cwd(), path.join('public', 'stylesheets')),
    JS_OPTIONS = {
        mangle: true,
        mangleProperties: true,
        compress: {
            properties: true,
            dead_code: true, // eslint-disable-line camelcase
            drop_debugger: true, // eslint-disable-line camelcase
            conditionals: true,
            evaluate: true,
            booleans: true,
            loops: true,
            unused: true,
            hoist_funs: true, // eslint-disable-line camelcase
            if_return: true, // eslint-disable-line camelcase
            join_vars: true, // eslint-disable-line camelcase
            cascade: true,
            collapse_vars: true, // eslint-disable-line camelcase
            pure_getters: true, // eslint-disable-line camelcase
            drop_console: true, // eslint-disable-line camelcase
            unsafe: true
        }
    };

/**
 * Parallely minifies javascript and stylesheets in SCRIPTS and STYLES respectively.
 *
 * @param {Function} next - The callback whose invocation marks the end of the minifacation routine.
 */
module.exports = function (next) {
    try {
        fs.mkdirSync(TARGET_DIR); // eslint-disable-line no-sync
    } catch (e) {} // eslint-disable-line no-empty, brace-style

    async.parallel({

        /**
         * Handles the minification of front end javascript in SCRIPTS.
         *
         * @param {Function} done - The callback that marks the completion of the JS minification routine.
         */
        js: function (done) {
            fs.readdir('public/javascripts', function (err, scripts) {
                if (err) { return done(err); }

                return async.each(scripts, function (script, callback) {
                    var target = path.join(TARGET_DIR, script),
                        content = uglifyJs.minify(path.join(SCRIPTS, script), JS_OPTIONS).code;

                    return script.endsWith('.js') ? fs.writeFile(target, content, callback) : callback();
                }, done);
            });
        },

        /**
         * Minifies stylesheets in the STYLES directory.
         *
         * @param {Function} done - The callback that marks the end of the stylesheet minification routine.
         */
        css: function (done) {
            fs.readdir(STYLES, function (err, styles) {
                if (err) { return done(err); }

                return async.each(styles, function (style, callback) {
                    var target = path.join(TARGET_DIR, style),
                        content = cleanCss.minify([path.join(STYLES, style)]).styles;

                    return style.endsWith('.css') ? fs.writeFile(target, content, callback) : callback();
                }, done);
            });
        }
    }, next);
};

!module.parent && module.exports(process.exit); // Directly call the exported function if used via the CLI.