Last active
January 20, 2023 08:23
-
-
Save acdlite/a68433004f9d6b4cbc83b5cc3990c194 to your computer and use it in GitHub Desktop.
Quick and dirty code splitting with React Router v4
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// 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 |
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)
so dirty and so good, bro
Thank you for this brilliant code. I've been using this code very usefully.
Since
System.import
is deprecated, you have to useimport
.Additionally, rather than doing
module => module.default
for every routes, you can remove some unnecessary codes by doing({default: Component}) => ...
in componentWillMountFull 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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
You have to use Either
<switch>
component to wrap routes (or)Exact
Attribute on<Route>