Allow Babel experimental plugins using package.json create-react-app.…

Created by: haraldrudell

fix for #3481 (closed)

test by adding Babel Function bind transform:

• run create-react-app
• npm i --save-dev babel-plugin-transform-function-bind
• add to package.json:

  "create-react-app": {
    "babel": {
      "plugins": [
        "transform-function-bind"
      ]
    }
  },

• modify src/App.js to use the experimental bind operator:

class App extends Component {
  constructor(o) {
    super(o)

    const thisf = ::this.f // this.f.bind(this) in ancient ECMAScript 2017
    const actualThis = thisf() // if bind no work: undefined

    const isCorrect = this.isCorrect = this === actualThis
    console.log(`this correct: ${isCorrect}`)
  }

  f() {
    return this
  }

  render() {
    return (
      <div className="App">bind operator working: {String(this.isCorrect)}

verify that npm t and npm start still works…

Awesome!