Gruntfile.js

module.exports = function(grunt) {
	grunt.initConfig({
		pkg : grunt.file.readJSON("package.json"),
		concat: {
			options : {
				banner : "/**\n" + 
				         " * <%= pkg.name %>\n" +
				         " *\n" +
				         " * @copyright <%= grunt.template.today('yyyy') %> <%= pkg.author %>\n" +
				         " * @license <%= pkg.license %>\n" +
				         " * @version <%= pkg.version %>\n" +
				         " */\n"
			},
			dist: {
				src : [
					"<banner>",
					"src/intro.js",
					"src/filesize.js",
					"src/outro.js"
				],
				dest : "lib/filesize.es6.js"
			}
		},
		"babel": {
			options: {
				sourceMap: false,
				presets: ["babel-preset-es2015"]
			},
			dist: {
				files: {
					"lib/<%= pkg.name %>.js": "lib/<%= pkg.name %>.es6.js"
				}
			}
		},
		eslint: {
			target: ["lib/<%= pkg.name %>.es6.js"]
		},
		nodeunit : {
			all : ["test/*.js"]
		},
		sed : {
			"version" : {
				pattern : "{{VERSION}}",
				replacement : "<%= pkg.version %>",
				path : ["<%= concat.dist.dest %>"]
			}
		},
		uglify: {
			options: {
				banner : "/*\n" +
				" <%= grunt.template.today('yyyy') %> <%= pkg.author.name %>\n" +
				" @version <%= pkg.version %>\n" +
				" */",
				sourceMap: true,
				sourceMapIncludeSources: true
			},
			target: {
				files: {
					"lib/filesize.min.js" : ["lib/filesize.js"]
				}
			}
		},
		watch : {
			js : {
				files : "<%= concat.dist.src %>",
				tasks : "build"
			},
			pkg: {
				files : "package.json",
				tasks : "build"
			}
		}
	});

	// tasks
	grunt.loadNpmTasks("grunt-sed");
	grunt.loadNpmTasks("grunt-contrib-concat");
	grunt.loadNpmTasks("grunt-contrib-nodeunit");
	grunt.loadNpmTasks('grunt-contrib-watch');
	grunt.loadNpmTasks("grunt-contrib-uglify");
	grunt.loadNpmTasks("grunt-babel");
	grunt.loadNpmTasks("grunt-eslint");

	// aliases
	grunt.registerTask("test", ["eslint", "nodeunit"]);
	grunt.registerTask("build", ["concat", "sed", "babel"]);
	grunt.registerTask("default", ["build", "test", "uglify"]);
};