Confused between the difference between JSX.Element vs React.Component and when to use them with Rea-CodePudding

I am starting out a new react-typescript project and I am using react-router-dom to manage routing but I am running into the following error in the browser counter:

Matched leaf route at location "/restaurant" does not have an element. This means it will render an <Outlet /> with a null value by default resulting in an "empty" page

Here's the code:

    <BrowserRouter>
                    <SiteNav hasItemInCart={false} numberOfItemsInCart={0}/>
                    <Routes>
                        <Route path="/home" children={Home} />
                        <Route path="/restaurant" children={Restaurant} />
                        <Route path="/hostel" children={Hostel} />
                    </Routes>
                </BrowserRouter>

export default class Home extends Component<any, any> {
    render() {
        return (
            <>
                <div>
                    Home
                </div>
            </>
        )
    }
}
class Hostel extends React.Component<any, any> {
    render() {
        return (
            <div className="Hostal">
                <body>Hostal</body>
            </div>
        );
    }
}

As I understand it I am suppose to return a JSX.element but typescript is throwing errors when I try to use it. Why can't I use React.Component? How should I do this instead?

CodePudding user response：

JSX.Element is the type of already rendered JSX. For example:

const a: JSX.Element = <>asd</>
const b: JSX.Element = <SomeComponent />

React.Component is the type of a component that knows how to produce a JSX.Element when rendered with specific props.

function A() { return <>Testing</> } // A is a component
const a: JSX.Element = <A />

Typically, children in React is a JSX.Element that you pass as the contents of a tag.

<A>
  <div>children go here</div>
</A>

Or you can use the children prop explicitly:

<A children={<div>children go here</div>} />

So in your case, you are passing a component to a prop that expects rendered content.

If you want to pass in rendered content, you want either:

<Route path="/home" children={<Home />} />

Or:

<Route path="/home"><Home/></Route>

Though modern version of react router recommend passing JSX to the element prop. So use this unless you're on an older version.

<Route path="/home" element={<Home />} />

CodePudding user response：

I think you are mixing up React types and the Route component API. In react-router-dom@6 there is now only an element prop (no component or render/children function props) taking a React.ReactNode, .a.k.a. any valid JSX.

Routes and Route

declare function Route(
  props: RouteProps
): React.ReactElement | null;

interface RouteProps {
  caseSensitive?: boolean;
  children?: React.ReactNode;
  element?: React.ReactNode | null;
  index?: boolean;
  path?: string;
}

You are passing your routed components to the Route using the RRDv5 Route component API/syntax. Convert your routes to use the element prop.

Example:

<BrowserRouter>
  <SiteNav hasItemInCart={false} numberOfItemsInCart={0} />
  <Routes>
    <Route path="/home" element={<Home />} />
    <Route path="/restaurant" element={<Restaurant />} />
    <Route path="/hostel" element={<Hostel />} />
  </Routes>
</BrowserRouter>

CodePudding user response：

What version of react-router-dom is in your package.json? This could be a versioning problem, on react-router-dom v6 all the routes are paired like this

[props.path]: [props.element]

That means, for example, for rendering a "hey" in a "/" path

<Route path="/" element={<div>Hey!</div>} />

In your case, you'd have to invoke for restaurants your <Restaurants /> component

<Route path="/" element={<Restaurants />} />