withSuspense() HOC for React.lazy() + React.Suspense

withSuspense.js

import React from 'react';
import { CircularProgress, LinearProgress } from '@material-ui/core/';

/**
 * Wraps the React Component with React.Suspense and FallbackComponent while loading.
 * @param {React.Component} WrappedComponent - lazy loading component to wrap.
 * @param {React.Component} FallbackComponent - component to show while the WrappedComponent is loading.
 */
export const withSuspense = (WrappedComponent, FallbackComponent = null) => {
	return class extends React.Component {
		render() {
			if (!FallbackComponent) FallbackComponent = <LinearProgress />; // by default
			return (
				<React.Suspense fallback={FallbackComponent}>
					<WrappedComponent {...this.props} />
				</React.Suspense>
			);
		}
	};
};

...

// Usage
const lazySomeComponent = React.lazy(() => import('./xxx/SomeComponent'));

export const SomeComponent = withSuspense(lazySomeComponent);
export const SomeComponentWithCircularProgress = withSuspense(lazySomeComponent, <CircularProgress />);
export const SomeComponentWithDiv = withSuspense(lazySomeComponent, <div>Loading...</div>);

Hey, thanks for this!
I have small suggestion: you can replace null with <LinearProgress /> in ...withSuspense = (WrappedComponent, FallbackComponent = <LinearProgress />) => ....

and you can get rid of check if its null if (!FallbackComponent) FallbackComponent = <LinearProgress />; // by default

Could be :)

@karpolan could you please help me ? Can I move import logic into the HOC ? I mean to move const lazySomeComponent = React.lazt(() => import('path')); into the withSuspense method?

You can, but in that case you need await loading...

I suggest to use following way:

import React from 'react';

/**
 * Note: Don't import/export all Views directly, use lazy loading!
 */
import { withSuspense } from '../components';
import NotFound from './NotFound';

/**
 * Views/Pages with Lazy Loading
 */
const Welcome = withSuspense(React.lazy(() => import('./Welcome')));
const About = withSuspense(React.lazy(() => import('./About')));
const MyProfile = withSuspense(React.lazy(() => import('./MyProfile')));

export { NotFound, Welcome, MyProfile, About };

@karpolan many thanks!

Nice! A comment on the naming - the argument you pass to Suspense's fallback prop is not actually a React component - it's a tree of React elements, in TS typed as ReactNode. So the naming FallbackComponent (capitalised, with "Component") is actually misleading - note you never write <FallbackComponent />. A better name for the second argument of the HOC would be simply fallback, or fallbackElement.