Babel6 + rollup.jsをやるにあたってちょっとハマった話 ref: http://qiita.com/inuscript/items/be4d437c4a935a241cd0

file0.txt

It looks like your Babel configuration specifies a module transformer. Please disable it. If you're using the "es2015" preset, consider using "es2015-rollup" instead. See https://github.com/rollup/rollup-plugin-babel#configuring-babel for more information
Error: It looks like your Babel configuration specifies a module transformer. Please disable it. If you're using the "es2015" preset, consider using "es2015-rollup" instead. See https://github.com/rollup/rollup-plugin-babel#configuring-babel for more information

file1.txt

$ npm install rollup -D
$ npm install rollup-plugin-babel -D
$ npm install babel-preset-es2015-rollup -D # これが必要

package.json

    :
  "babel": {
    "presets": [
      "es2015-rollup"
    ]
  },
   :

rollup.config.js

import babel from "rollup-plugin-babel"
export default {
  entry: "src/index.js",
  dest: "dest/index.js",
  plugins: [babel()]
}