Lazy Loading



Lazy Loading:

 

1. Create an asyncComponent.js:

 

import React, { Component } from 'react';

 

const asyncComponent = (importComponent) => {

    return class extends Component {

        state = {

            component: null

        }

 

        componentDidMount () {

            importComponent()

                .then(cmp => {

                    this.setState({component: cmp.default});

                });

        }

       

        render () {

            const C = this.state.component;

 

            return C ? <C {...this.props} /> : null;

        }

    }

}

 

export default asyncComponent;

 

2. In the main App.js where we have all the routing setup:

 

import asyncComponent from './hoc/asyncComponent/asyncComponent';

 

instead of

 

import MyComponent from '../path/to/MyComponent';

 

load the component asynchronously using the following code:

 

const asyncMyComponent = asyncComponent(() => {

  return import('../path/to/MyComponent');

});

 

And in the routing use the async component:

 

<Switch>

                <Route path="/mycomponentpath" component={asyncMyComponent} />

                <Redirect to="/" />

</Switch>

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