gistfile1.txt

//works
const decorate = (Component, body={}) => {
  class Wrapper extends React.Component {
    constructor() { return super() }
    render() { return <Component {...this.props} /> }

    static getInitialProps = body.getInitialProps
  }

  for (const key in body) {
    Wrapper.prototype[key] = body[key]
  }

  return Wrapper
}

// does not
const decorate = (Component, body={}) => {
  class Wrapper extends React.Component {
    constructor() { return super() }
    render() { return <Component {...this.props} /> }

    static getInitialProps = body.getInitialProps
  }

  Wrapper.prototype = body

  return Wrapper
}

i get

TypeError: Cannot call a class as a function
    at exports.default (/Users/dade/work/grocerest/grocerest-webapp/node_modules/babel-runtime/helpers/classCallCheck.js:7:11)
    at Wrapper (/Users/dade/work/grocerest/grocerest-webapp/.next/dist/pages/index.js:109:36)
    at /Users/dade/work/grocerest/grocerest-webapp/node_modules/react/lib/ReactCompositeComponent.js:305:16
    at measureLifeCyclePerf (/Users/dade/work/grocerest/grocerest-webapp/node_modules/react/lib/ReactCompositeComponent.js:74:12)
    at ReactCompositeComponentMixin._constructComponentWithoutOwner (/Users/dade/work/grocerest/grocerest-webapp/node_modules/react/lib/ReactCompositeComponent.js:304:14)
    at ReactCompositeComponentMixin._constructComponent (/Users/dade/work/grocerest/grocerest-webapp/node_modules/react/lib/ReactCompositeComponent.js:279:21)
    at ReactCompositeComponentMixin.mountComponent (/Users/dade/work/grocerest/grocerest-webapp/node_modules/react/lib/ReactCompositeComponent.js:187:21)
    at Object.ReactReconciler.mountComponent (/Users/dade/work/grocerest/grocerest-webapp/node_modules/react/lib/ReactReconciler.js:47:35)
    at ReactCompositeComponentMixin.performInitialMount (/Users/dade/work/grocerest/grocerest-webapp/node_modules/react/lib/ReactCompositeComponent.js:370:34)
    at ReactCompositeComponentMixin.mountComponent (/Users/dade/work/grocerest/grocerest-webapp/node_modules/react/lib/ReactCompositeComponent.js:257:21)