acdlite/app.js

eonezhang · 2017-06-09T07:43:34Z

@acdlite, is there any idea on loading the asyncComponent related reducers together, and inject the reducers into the store?
I have implemented the injectHelper.

function createReducer(asyncReducers) {
  return combineReducers({
    ...asyncReducers,
    system,
    router,
  })
}

function injectReducer(store, { key, reducer }) {
  if (Reflect.has(store.asyncReducers, key)) return

  store.asyncReducers[key] = reducer // eslint-disable-line no-param-reassign
  store.replaceReducer(createReducer(store.asyncReducers))
}

MorganeLecurieux · 2017-07-03T13:35:11Z

@acdlite, thanks for you solution it's working perfectly.
Right now, I'm trying to prefetch the async bundles (I have a "setup" on my app, and I know my users will later navigate to an other view).
The prefetched bundles are fine, however when I navigate on an other view, the bundle is reloaded like it haven't been before.
Any idea how to solve the problem please ? I've been trying several things for a few days now and can't get a hint of what's going on on the async bundles...
Thanks :)

ethan-deng · 2017-08-20T04:07:43Z

Will the component js file be loaded more than once if the component unmounted and mounted again in the case such as React router. In the case of the code is not splitted, one bundle.js file is loaded just once.

titanve · 2017-10-01T00:22:23Z

Hello everyone!

I'm using this code:

import React from "react";
import {
  BrowserRouter as Router,
  Route,
  Link,
  Switch,
  Redirect,
  Match
} from "react-router-dom";
// import Bundle from "Bundle/Bundle";

// import PedidoApp from "bundle-loader?lazy!./PedidoApp";
// import PedidoForm from "bundle-loader?lazy!./pedidoform";

// getComponent is a function that returns a promise for a component
// It will not be called until the first mount
const asyncComponent = getComponent => {
  return class AsyncComponent extends React.Component {
    static Component = null;
    state = { Component: AsyncComponent.Component };

    componentWillMount() {
      if (!this.state.Component) {
        getComponent().then(({ default: Component }) => {
          AsyncComponent.Component = Component;
          this.setState({ Component });
        });
      }
    }
    render() {
      const { Component } = this.state;
      if (Component) {
        return <Component {...this.props} />;
      }
      return null;
    }
  };
};

const PedidoApp = asyncComponent(() => import("./PedidoApp"));
const PedidoForm = asyncComponent(() => import("./pedidoform"));

class Root extends React.Component {
  render() {
    return (
      <Router>
        <div>
          <Link to="/pedido-1">Pedido</Link>
          <Link to="/pedido-1/add">Agregar</Link>

          <Route pattern="/pedido-1" component={PedidoApp} />
          <Route pattern="/pedido-1/add" component={PedidoForm} />
          <Redirect path="*" to="/pedido-1" />
        </div>
      </Router>
    );
  }
}

export default Root;

But it shows both components at the same time. How do I do in order to show <PedidoApp/> by default (Home) and when I click the Add button (or edit) show <PedidoForm/> ???

Thank you

dleitee · 2017-10-11T20:50:43Z

Hello,

I've implemented with recompose:

import React from 'react'
import { lifecycle } from 'recompose'

export default getComponent => {
  const setLifecycle = lifecycle({
    state: {
      Component: undefined,
    },
    componentWillMount() {
      if (!this.props.Component) {
        getComponent().then(Component => {
          this.setState({ Component })
        })
      }
    },
  })
  const AsyncComponent = props => {
    const { Component, ...otherProps } = props
    if (Component) {
      return <Component {...otherProps} />
    }
    return undefined
  }

  return setLifecycle(AsyncComponent)
}

harshes53 · 2017-10-27T02:06:32Z

@titanve use Switch, refer docs here

Anenth · 2017-11-03T11:51:53Z

export class LazyLoadComponent extends Component {
    constructor(props) {
        super(props);
        this.state = {
            fetched_module: null
        };
    }

    componentWillMount() {
        if (!this.state.fetched_module) {
            System.import(this.props.file_location)
                .then(fetched_component => {
                    this.setState({fetched_module: fetched_component.default});
                });
        }
    }

    render() {
        const CurrentComponent = this.state.fetched_module;
        const {loading_page, ...component_props} = this.props;

        if (CurrentComponent) {
            return (<CurrentComponent {...component_props} />);
        }
        return (<LoadingPage page={loading_page}/>);
    }
}

LazyLoadComponent.propTypes = {
    file_location: PropTypes.string.isRequired,
    loading_page: PropTypes.string
};

Something like this won't work?

budarin · 2017-11-20T22:55:38Z

After rendering route component on a server I have FOT because when React initializes app - asyncComponent renders null at first time!
The second problem is about Stores keys - reducers of the route component will be injected into main reducer when it will be loaded.
But at that time server state is lost the keys which are belonged to the loaded component - so SSR is useless ! ((
Is there a solution of these problems?

aerosunilkumar · 2017-12-14T08:41:03Z

can any one help me to solve this

ashokrao1 · 2017-12-22T08:28:01Z

@aerosunilkumar, transpile using https://babeljs.io/docs/plugins/preset-stage-0/

ashokrao1 · 2017-12-22T08:29:00Z

Thanks for this awesome post, made my life lot easier :)

budarin · 2017-12-26T06:01:23Z

@acdlite
What is the main purpose of having static Component field?

AndrejGajdos · 2018-02-06T14:41:41Z

@acdlite I have the same question as @budarin

nateq314 · 2018-02-26T23:56:38Z

@budarin @AndreGajdos It's memoization. It's caching it for the next time the component is used. First time it will do the fetch. Every time thereafter it will already be there in the static Component field.

nhulongctk10 · 2018-03-01T08:46:16Z

I have the same question as @budarin.

ghost · 2018-04-04T11:07:50Z

How we can add progress until component not import.
I want to use this type of progress.

mrukas · 2018-04-08T13:00:50Z

@nateq314 This should only be necessary if you're using something other than webpack. Using webpack the module only gets fetched one time, even if you're not caching the component in the static field.

How do I pass props to the lazy loaded component? I see that {...this.props} has been used, but you can't pass properties to the AsyncComponent. Am I missing something?

I'm currently using something like this:

export default function asyncComponent(getComponent, props = {}) {
    return class AsyncComponent extends Component {
        state = {};

        componentWillMount() {
            getComponent().then(({ default: component }) => {
                this.setState({ Component: component });
            });
        }

        render() {
            const { Component } = this.state
            return Component ? <Component {...props} /> : null;
        }
    };
}

The route entry looks like this:

 <Route path="/about" component={asyncRoute(() => import('./About'), { title: "About" })} />

elycruz · 2018-04-21T03:03:23Z

Nice!!!

I would use FetchedComponent or something internally instead of Component (since you're probably already importing that symbol (Component)).

Other than that awesome!

49-22 · 2018-11-03T10:44:23Z

Hello everyone!

I'm using this code:

import React from "react";
import {
  BrowserRouter as Router,
  Route,
  Link,
  Switch,
  Redirect,
  Match
} from "react-router-dom";
// import Bundle from "Bundle/Bundle";

// import PedidoApp from "bundle-loader?lazy!./PedidoApp";
// import PedidoForm from "bundle-loader?lazy!./pedidoform";

// getComponent is a function that returns a promise for a component
// It will not be called until the first mount
const asyncComponent = getComponent => {
  return class AsyncComponent extends React.Component {
    static Component = null;
    state = { Component: AsyncComponent.Component };

    componentWillMount() {
      if (!this.state.Component) {
        getComponent().then(({ default: Component }) => {
          AsyncComponent.Component = Component;
          this.setState({ Component });
        });
      }
    }
    render() {
      const { Component } = this.state;
      if (Component) {
        return <Component {...this.props} />;
      }
      return null;
    }
  };
};

const PedidoApp = asyncComponent(() => import("./PedidoApp"));
const PedidoForm = asyncComponent(() => import("./pedidoform"));

class Root extends React.Component {
  render() {
    return (
      <Router>
        <div>
          <Link to="/pedido-1">Pedido</Link>
          <Link to="/pedido-1/add">Agregar</Link>

          <Route pattern="/pedido-1" component={PedidoApp} />
          <Route pattern="/pedido-1/add" component={PedidoForm} />
          <Redirect path="*" to="/pedido-1" />
        </div>
      </Router>
    );
  }
}

export default Root;

But it shows both components at the same time. How do I do in order to show <PedidoApp/> by default (Home) and when I click the Add button (or edit) show <PedidoForm/> ???

Thank you

You have to use Either <switch> component to wrap routes (or) Exact Attribute on <Route>

StefanoSega · 2019-04-01T05:28:45Z

Hello!

Writing an async component like this in TypeScript:

export function routeAsyncComponent(getComponent: () => Promise<React.Component>) {
  interface IRouteAsyncComponentState {
    Component: React.Component;
  }

  return class RouteAsyncComponent extends React.Component<any, IRouteAsyncComponentState> {
    static Component: React.Component = null;
    state = { Component: RouteAsyncComponent.Component };

    componentWillMount() {
      if (!this.state.Component) {
        getComponent().then(Component => {
          RouteAsyncComponent.Component = Component;
          this.setState({ Component });
        });
      }
    }
    render() {
      const { Component } = this.state;
      if (Component) {
        return <Component {...this.props} />;
      }

      return null;
    }
  }
}

TypeScript complains on return <Component {...this.props} />; :

Type assertion using the '<>' syntax is forbidden. Use the 'as' syntax instead. (no-angle-bracket-type-assertion)tslint(1)

Type assertion on object literals is forbidden, use a type annotation instead. (no-object-literal-type-assertion)tslint(1)

Cannot find name 'Component'.ts(2304)

BertieGo · 2020-01-16T06:49:56Z

so dirty and so good, bro

lynda0214 · 2020-12-08T10:16:28Z

Thank you for this brilliant code. I've been using this code very usefully.

Since System.import is deprecated, you have to use import.

Additionally, rather than doing module => module.default for every routes, you can remove some unnecessary codes by doing ({default: Component}) => ... in componentWillMount

Full Code:

function asyncComponent(getComponent) {
  return class AsyncComponent extends React.Component {
    static Component = null;
    state = { Component: AsyncComponent.Component };

    componentWillMount() {
      if (!this.state.Component) {
        getComponent().then(({default: Component}) => {
          AsyncComponent.Component = Component
          this.setState({ Component })
        })
      }
    }
    render() {
      const { Component } = this.state
      if (Component) {
        return <Component {...this.props} />
      }
      return null
    }
  }
}

const Foo = asyncComponent(() => import('./Foo'))
const Bar = asyncComponent(() => import('./Bar'))

Can't figure out why .default is needed

acdlite/app.js

eonezhang commented Jun 9, 2017 •

edited

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MorganeLecurieux commented Jul 3, 2017

ethan-deng commented Aug 20, 2017

titanve commented Oct 1, 2017 •

edited

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dleitee commented Oct 11, 2017

harshes53 commented Oct 27, 2017 •

edited

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Anenth commented Nov 3, 2017 •

edited

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budarin commented Nov 20, 2017

aerosunilkumar commented Dec 14, 2017

ashokrao1 commented Dec 22, 2017

ashokrao1 commented Dec 22, 2017

budarin commented Dec 26, 2017 •

edited

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AndrejGajdos commented Feb 6, 2018 •

edited

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nateq314 commented Feb 26, 2018

nhulongctk10 commented Mar 1, 2018

ghost commented Apr 4, 2018 •

edited by ghost

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mrukas commented Apr 8, 2018

elycruz commented Apr 21, 2018

49-22 commented Nov 3, 2018

StefanoSega commented Apr 1, 2019

BertieGo commented Jan 16, 2020

lynda0214 commented Dec 8, 2020

	// getComponent is a function that returns a promise for a component
	// It will not be called until the first mount
	function asyncComponent(getComponent) {
	return class AsyncComponent extends React.Component {
	static Component = null;
	state = { Component: AsyncComponent.Component };

	componentWillMount() {
	if (!this.state.Component) {
	getComponent().then(Component => {
	AsyncComponent.Component = Component
	this.setState({ Component })
	})
	}
	}
	render() {
	const { Component } = this.state
	if (Component) {
	return <Component {...this.props} />
	}
	return null
	}
	}
	}

	const Foo = asyncComponent(() =>
	System.import('./Foo').then(module => module.default)
	)
	const Bar = asyncComponent(() =>
	System.import('./Bar').then(module => module.default)
	)

	const App = () =>
	<BrowserRouter>
	<Link to="/foo">Foo</Link>
	<Link to="/bar">Bar</Link>

	<Match pattern="/foo" component={Foo} />
	<Match pattern="/bar" component={Bar} />
	</BrowserRouter>

	export default App

acdlite/app.js

eonezhang commented Jun 9, 2017 • edited Loading

MorganeLecurieux commented Jul 3, 2017

ethan-deng commented Aug 20, 2017

titanve commented Oct 1, 2017 • edited Loading

dleitee commented Oct 11, 2017

harshes53 commented Oct 27, 2017 • edited Loading

Anenth commented Nov 3, 2017 • edited Loading

budarin commented Nov 20, 2017

aerosunilkumar commented Dec 14, 2017

ashokrao1 commented Dec 22, 2017

ashokrao1 commented Dec 22, 2017

budarin commented Dec 26, 2017 • edited Loading

AndrejGajdos commented Feb 6, 2018 • edited Loading

nateq314 commented Feb 26, 2018

nhulongctk10 commented Mar 1, 2018

ghost commented Apr 4, 2018 • edited by ghost Loading

mrukas commented Apr 8, 2018

elycruz commented Apr 21, 2018

49-22 commented Nov 3, 2018

StefanoSega commented Apr 1, 2019

BertieGo commented Jan 16, 2020

lynda0214 commented Dec 8, 2020

eonezhang commented Jun 9, 2017 •

edited

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titanve commented Oct 1, 2017 •

edited

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harshes53 commented Oct 27, 2017 •

edited

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Anenth commented Nov 3, 2017 •

edited

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budarin commented Dec 26, 2017 •

edited

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AndrejGajdos commented Feb 6, 2018 •

edited

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ghost commented Apr 4, 2018 •

edited by ghost

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