Gruntfile.js

module.exports = function(grunt) {

  require('load-grunt-tasks')(grunt);

  grunt.loadNpmTasks('grunt-execute');
  grunt.loadNpmTasks('grunt-contrib-clean');
  grunt.loadNpmTasks('grunt-contrib-watch');


    grunt.initConfig({

    clean: ["dist"],

    copy: {
      src_to_dist: {
        cwd: 'src',
        expand: true,
        src: ['**/*', '**/*.js', '!**/*.scss'],
        dest: 'dist'
      },
      pluginDef: {
        expand: true,
        src: ['README.md'],
        dest: 'dist'
      }
    },

    watch: {
      rebuild_all: {
        files: ['src/**/*'],
        tasks: ['watch-ts'],
        options: {spawn: false}
      }
    },

    typescript: {
      build: {
        src: ['dist/**/*.ts', "!src/spec/**/*", "!**/*.d.ts"],
        dest: 'dist/',
        options: {
          module: 'system', //or commonjs
          target: 'es3', //or es5
          rootDir: 'dist/',
          keepDirectoryHierarchy: false,
          declaration: true,
          emitDecoratorMetadata: true,
          experimentalDecorators: true,
          sourceMap: true,
          noImplicitAny: false,
        }
      },
      distTests: {
        src: ['src/**/*.ts', "!src/spec/**/*", "!**/*.d.ts"],
        dest: 'dist/test/',
        options: {
          module: 'commonjs', //or commonjs
          target: 'es5', //or es5
          rootDir: 'src/',
          sourceRoot: 'src/',
          declaration: true,
          emitDecoratorMetadata: true,
          experimentalDecorators: true,
          sourceMap: true,
          noImplicitAny: false,
        }
      },
      // distTestsSpecs: {
      //   src: ['src/spec/**/*.ts'],
      //   dest: 'dist/test/',
      //   options: {
      //     module: 'commonjs', //or commonjs
      //     target: 'es5', //or es5
      //     declaration: true,
      //     emitDecoratorMetadata: true,
      //     experimentalDecorators: true,
      //     sourceMap: true,
      //     noImplicitAny: false,
      //   }
      // }
    },

    // babel: {
    //   options: {
    //     sourceMap: true,
    //     presets:  ['es2015']
    //   },
    //   distTestsSpecsNoSystemJs: {
    //     files: [{
    //       expand: true,
    //       cwd: 'src/spec',
    //       src: ['**/*.js'],
    //       dest: 'dist/test/spec',
    //       ext:'.js'
    //     }]
    //   }
    // },

    // mochaTest: {
    //   test: {
    //     options: {
    //       reporter: 'spec'
    //     },
    //     src: ['dist/test/spec/test-main.js', 'dist/test/spec/*_specs.js']
    //   }
    // }
  });

  grunt.registerTask('default', [
    'clean',
    'copy',
    'typescript:build',
    'typescript:distTests'
    // 'babel',
    // 'mochaTest'
  ]);

  grunt.registerTask('watch-ts', [
    'clean',
    'copy:src_to_dist',
    'copy:pluginDef',
    'typescript:build'
  ]);
};