Gruntfile.js

/**
 * Plugin base arguments
 *
 * @type {Object}
 */
var plugin_args = {
	path       : './', // plugin directory path
	domainPath : '/languages', // language files location ( relative to "path" )
	potFilename: 'template.pot', // generated pot file name
	exclude    : [ // excluded files and directory from parsing
		'vendor/' // composer libs vendor dir
	],
	mainFile   : 'init.php', // plugin main file ( with plugin description comment doc )
	watchFiles : {
		assets : [ 'assets/src/css/**/*.css', 'assets/src/js/**/*.js' ],
		potfile: [ './**/*.php' ]
	}
};

// requires
var fs = require( 'fs' );

/**
 * Grunt tasks
 */
module.exports = function ( grunt ) {
	// Project configuration.
	grunt.initConfig( {
		pkg    : grunt.file.readJSON( 'package.json' ),
		uglify : {
			my_target: {
				options: {
					preserveComments: 'some'
				},
				files  : [ {
					expand: true,
					cwd   : 'assets/src/js',
					src   : '**/*.js',
					dest  : 'assets/dist/js'
				} ]
			}
		},
		cssmin : {
			minify: {
				expand: true,
				cwd   : 'assets/src/css',
				src   : '**/*.css',
				dest  : 'assets/dist/css'
			}
		},
		makepot: {
			target: {
				options: {
					cwd            : plugin_args.path,
					domainPath     : plugin_args.domainPath,
					exclude        : plugin_args.exclude,
					mainFile       : plugin_args.mainFile,
					potFilename    : plugin_args.potFilename,
					potHeaders     : {
						poedit                 : true,
						'x-poedit-keywordslist': true,
						'Last-Translator'      : '',
						'Language-Team'        : 'Nabeel Molham <n.molham@gmail.com>'
					},
					type           : 'wp-plugin',
					updateTimestamp: true,
					updatePoFiles  : true
				}
			}
		},
		watch  : {
			// for localization .pot file
			potfile: {
				files: plugin_args.watchFiles.potfile,
				tasks: [ 'makepot' ]
			},
			// for JS & CSS assets
			assets : {
				files: plugin_args.watchFiles.assets,
				tasks: [ 'uglify', 'cssmin' ]
			},
			// for JS & CSS assets
			all    : {
				files: plugin_args.watchFiles.potfile.concat( plugin_args.watchFiles.assets ),
				tasks: [ 'makepot', 'uglify', 'cssmin' ]
			}
		}
	} );

	// Load plugins
	grunt.loadNpmTasks( 'grunt-wp-i18n' );
	grunt.loadNpmTasks( 'grunt-contrib-uglify' );
	grunt.loadNpmTasks( 'grunt-contrib-cssmin' );
	grunt.loadNpmTasks( 'grunt-contrib-watch' );

	// when the watch task triggers
	grunt.event.on( 'watch', function () {
		fs.writeFile( "assets/last_update", (new Date()).toISOString().replace( /[^0-9]/g, '' ), function ( err ) {
			if ( err ) {
				return console.log( err );
			}

			console.log( "The watch file was saved!" );
		} );
	} );

	// Default task(s).
	grunt.registerTask( 'default', [ 'watch:all' ] );
};