Functions are not valid as a React child. This may happen if you return a Component instead of from render

Question

I have written a Higher Order Component:

import React from \'react\';


const NewHOC = (PassedComponent) => {
    return class extends React.Component {
          


        

Answer 1

You are using it as a regular component, but it's actually a function that returns a component.

Try doing something like this:

const NewComponent = NewHOC(Movie)

And you will use it like this:

<NewComponent someProp="someValue" />

Here is a running example:

const NewHOC = (PassedComponent) => {
  return class extends React.Component {
    render() {
      return (
        <div>
          <PassedComponent {...this.props} />
        </div>
      )
    }
  }
}

const Movie = ({name}) => <div>{name}</div>

const NewComponent = NewHOC(Movie);

function App() {
  return (
    <div>
      <NewComponent name="Kill Bill" />
    </div>
  );
}

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="root"/>

So basically NewHOC is just a function that accepts a component and returns a new component that renders the component passed in. We usually use this pattern to enhance components and share logic or data.

You can read about HOCS in the docs and I also recommend reading about the difference between react elements and components

I wrote an article about the different ways and patterns of sharing logic in react.

Answer 2

I was getting this from webpack lazy loading like this

import Loader from 'some-loader-component';
const WishlistPageComponent = loadable(() => import(/* webpackChunkName: 'WishlistPage' */'../components/WishlistView/WishlistPage'), {
  fallback: Loader, // warning
});
render() {
    return <WishlistPageComponent />;
}


// changed to this then it's suddenly fine
const WishlistPageComponent = loadable(() => import(/* webpackChunkName: 'WishlistPage' */'../components/WishlistView/WishlistPage'), {
  fallback: '', // all good
});