Gruntfile.js

module.exports = function(grunt) {
  "use strict";
  require("jit-grunt")(grunt);
  require("load-grunt-tasks")(grunt); // npm install --save-dev load-grunt-tasks

  function sourceMap(path) {
    if (grunt.file.exists(path)) {
      return grunt.file.readJSON(path);
    }
  }

  grunt.initConfig({
    babel: {
      options: {
        sourceMap: true,
        inputSourceMap: sourceMap("build/js/main.js.map")
      },
      dist: {
        src: ["build/js/main.js"],
        dest: "build/js/main.js"
      }
    },
    jshint: {
      options: {
        jshintrc: true
      },
      all: ["src/**/*.js"]
    },

    sass: {
      project: {
        files: {
          "build/css/main.css": "src/scss/main.scss"
        }
      }
    },

    watch: {
      js: {
        files: ["src/**/*.js"],
        tasks: ["js-build"]
      },
      sass: {
        files: ["src/**/*.scss"],
        tasks: ["css-build"]
      },
      html: {
        files: ["src/**/*.html"],
        tasks: ["copy:html"]
      }
    },

    clean: ["build/"],

    concat: {
      options: {
        seperator: ";",
        sourceMap: true
      },
      js: {
        src: [
          "node_modules/react/dist/react.min.js",
          "node_modules/react-dom/dist/react-dom.min.js",
          "src/js/components/*.js",
          "src/js/client.js"
        ],
        dest: "build/js/main.js"
      },
      server: {
        src: ["src/server/*.js"],
        dest: "build/server/app.js"
      }
    },

    copy: {
      html: {
        expand: true,
        src: ["**/*.html"],
        dest: "build/",
        cwd: "src/"
      },
      js: {
        expand: true,
        src: ["**/*.js"],
        dest: "build/js/",
        cwd: "vendor/"
      },
      img: {
        expand: true,
        src: ["**/*.png", "**/*.ico", "**/*.jpg"],
        dest: "build/",
        cwd: "src/"
      }
    }
  });

  require("time-grunt")(grunt);

  grunt.registerTask("js-build", ["concat:js", "babel"]);
  grunt.registerTask("css-build", ["sass"]);
  grunt.registerTask("default", ["clean", "copy", "concat", "babel", "sass"]);
};