import books from '../books'
function BookScreen({ match }) {
const book = books.find((b) => b._id === match.params.id)
return (
<div>
{book}
</div>
)
}
export default BookScreen
I keep getting the error match is undefined. I saw a tutorial with similar code, but it seemed fine when put to the test. Any clue what might be the issue?
If match prop is undefined this could be from a few things.
react-router-dom v5
If using RRDv5 if the match prop is undefined this means that BookScreen isn't receiving the route props that are injected when a component is rendered on the Route component's component prop, or the render or children prop functions. Note that using children the route will match and render regardless, see route render methods for details.
Ensure that one of the following is implemented to access the match object:
Render BookScreen on the component prop of a Route
<Route path="...." component={BookScreen} />
Render BookScreen on the render or children prop function of a Route and pass the route props through
<Route path="...." render={props => <BookScreen {...props} />} />
or
<Route path="...." children={props => <BookScreen {...props} />} />
Decorate BookScreen with the withRouter Higher Order Component to have the route props injected
import { withRouter } from 'react-router-dom';
function BookScreen = ({ match }) {
const book = books.find((b) => b._id === match.params.id)
return (
<div>
{book}
</div>
);
};
export default withRouter(BookScreen);
Since BookScreen is a React function component, import and use the useParams hook to access the route match params
import { useParams } from 'react-router-dom';
...
function BookScreen() {
const { id } = useParams();
const book = books.find((b) => b._id === id)
return (
<div>
{book}
</div>
);
}
react-router-dom v6
If using RRDv6 then there is no match prop. Gone are the route props. Here only the useParams and other hooks exist, so use them.
import { useParams } from 'react-router-dom';
...
function BookScreen() {
const { id } = useParams();
const book = books.find((b) => b._id === id)
return (
<div>
{book}
</div>
);
}
If you've other class components and you're using RRDv6 and you don't want to convert them to function components, then you'll need to create a custom withRouter component. See my answer here with details.
I guess you rendered BookScreen component before match is initialized. This is why match is undefined when BookScreen rendered. Render it conditionally like below.
return (
... other components
{match && <BookScreen match={match}/>}
)
Also, I leave useful site which tells you some good ways to do that. :D
https://www.digitalocean.com/community/tutorials/7-ways-to-implement-conditional-rendering-in-react-applications
I hope you find an answer :D
i'm new at React. Basically i want to call different components based on the string passed as props. I've component named Device that have as prop the name of a particular device and in Device i want to call another components which has as name the props. Something like this: <DeviceName/>
This is my code:
App.js
<Device name = {devName} />
Device.js
import DeviceMark from ./devices/DeviceMark
function DeviceName({devName}) {
const DevName = devName;
return (
<Router>
<Switch>
<Route path = "/" exact><DevName /></Route>
</Switch>
</Router>
)
}
Imagine that in this case DevName will replace DeviceMark
When you really need to convert string component names to actual components while rendering, I can suggest following way
import DeviceMark from ./devices/DeviceMark
function DeviceName({devName}) {
const mappingComponents = {
foo: FooComponent,
bar: BarComponent,
deviceMark: DeviceMark
};
const ComponentToRender = mappingComponents[devName || 'foo'];
return (
<Router>
<Switch>
<Route path = "/" exact><ComponentToRender></ComponentToRender></Route>
</Switch>
</Router>
)
}
More details in official doc - https://reactjs.org/docs/jsx-in-depth.html
I guess you need to use React.createElement. It allows to create React element from string (if it's a basic html tag) or from function (if it's a React component).
import React from 'react'
import ReactDOM from 'react-dom'
const DeviceName = () => {
return 'sub component'
}
const Device = ({subDev}) => {
return (
<div>
{ React.createElement(subDev) }
</div>
)
}
function App() {
return <Device subDev={DeviceName} />
}
ReactDOM.render(<App />, document.getElementById('root'))
It's a little example. I have a main component Device. It accepts a sub-component via a prop and I pass sub-component to createElement. It does not matter if sub-component whether basic html tag or React component.
It's codesandbox example.
I have the following line of code:
<Route path="/users/:id" exact ><User url={structure.users} /></Route>
In User component I do the following:
function User(props, {match}) {
useEffect(() => {
console.log(match);
console.log(props);
}, [props]);
// ...
}
I removed a bit of the code because I only want to show what is necessary but here I see that match is undefined but it should have match.params.id from the link. How can I achieve this so i can make the full url with the url with the attached id?
React components receive only a single props object argument.
Use the Route's render prop so you can pass the route props on to the component.
<Route
path="/users/:id"
exact
render={routeProps => <User url={structure.users} {...routeProps} />}
/>
Alternatively you can use the useParams React hook to access match.params of the current Route.
import { ...., useParams, .... } from 'react-router-dom';
function User(props) {
const { id } = useParams();
useEffect(() => {
console.log(id);
console.log(props);
}, [props]);
// ...
}
I have a simple setup to test the use of the useContext hook, when you want to change the context value in child components.
A simple Context is defined in its own file like such:
import React from 'react'
const DataContext = React.createContext({})
export const DataProvider = DataContext.Provider
export default DataContext
Then I wrap my router in a provider in a component that exposes its state to use as a reference for the ContextProvider, as such:
import { DataProvider } from './dataContext.js'
export default function App(props) {
const [data, setData] = useState("Hello!")
const value = { data, setData }
const hist = createBrowserHistory();
return (
<DataProvider value={value}>
<Router history={hist}>
<Switch>
<Route path="/admin" component={Admin} />
<Redirect from="/" to="/admin/services" />
</Switch>
</Router>
</DataProvider>
)
}
Finally I have two Views that I am able to navigate between initially, one of them showcasing the context value, as well as containing a button to change it:
export default function EndpointView(props) {
const { data, setData } = useContext(DataContext)
return (
<div>
<h1>{data}!</h1>
<Button onClick={() => setData(Math.random())}>Update context state</Button>
</div>
)
}
The functionality seems to work, as the showcases text is updated.
The problem is, when I have clicked the button, I can no longer navigate in my navbar, even though the url is changing. Any ideas as to why?
This is showcased in this picture, where the url is corresponding to the top-most item in the side bar, even though we are stuck in the "endpoint view"-component.
Edit:
So the routing works by including a switch in the Admin layout:
const switchRoutes = (
<Switch>
{routes.map((prop, key) => {
if (prop.layout === "/admin") {
return (
<Route
path={prop.layout + prop.path}
component={prop.component}
key={key}
/>
);
}
return null;
})}
<Redirect from="/admin" to="/admin/services" />
</Switch>
);
Where the routes (which we .map) are fetched from another file that looks like this:
const dashboardRoutes = [
{
path: "/services",
name: "Services view",
icon: AccountBalance,
component: ServicesView,
layout: "/admin"
},
{
path: "/endpoint",
name: "Endpoint view",
icon: FlashOn,
component: EndpointView,
layout: "/admin"
}
];
export default dashboardRoutes;
I was able to solve this issue.
I suspect the problem was that updating the state reloaded the root router component which caused some issues.
Instead I moved the DataProvider tag one step down the tree, to wrap the switch in the Admin component.
Test Case
https://codesandbox.io/s/rr00y9w2wm
Steps to reproduce
Click on Topics
Click on Rendering with React
OR
Go to https://rr00y9w2wm.codesandbox.io/topics/rendering
Expected Behavior
match.params.topicId should be identical from both the parent Topics component should be the same as match.params.topicId when accessed within the Topic component
Actual Behavior
match.params.topicId when accessed within the Topic component is undefined
match.params.topicId when accessed within the Topics component is rendering
I understand from this closed issue that this is not necessarily a bug.
This requirement is super common among users who want to create a run in the mill web application where a component Topics at a parent level needs to access the match.params.paramId where paramId is a URL param that matches a nested (child) component Topic:
const Topic = ({ match }) => (
<div>
<h2>Topic ID param from Topic Components</h2>
<h3>{match.params.topicId}</h3>
</div>
);
const Topics = ({ match }) => (
<div>
<h2>Topics</h2>
<h3>{match.params.topicId || "undefined"}</h3>
<Route path={`${match.url}/:topicId`} component={Topic} />
...
</div>
);
In a generic sense, Topics could be a Drawer or Navigation Menu component and Topic could be any child component, like it is in the application I'm developing. The child component has it's own :topicId param which has it's own (let's say) <Route path="sections/:sectionId" component={Section} /> Route/Component.
Even more painful, the Navigation Menu needn't have a one-to-one relationship with the component tree. Sometimes the items at the root level of the menu (say Topics, Sections etc.) might correspond to a nested structure (Sections is only rendered under a Topic, /topics/:topicId/sections/:sectionId though it has its own normalized list that is available to the user under the title Sections in the Navigation Bar).
Therefore, when Sections is clicked, it should be highlighted, and not both Sections and Topics.
With the sectionId or sections path unavailable to the Navigation Bar component which is at the Root level of the application, it becomes necessary to write hacks like this for such a commonplace use case.
I am not an expert at all at React Router, so if anyone can venture a proper elegant solution to this use case, I would consider this to be a fruitful endeavor. And by elegant, I mean
Uses match and not history.location.pathname
Does not involve hacky approaches like manually parsing the window.location.xxx
Doesn't use this.props.location.pathname
Does not use third party libraries like path-to-regexp
Does not use query params
Other hacks/partial solutions/related questions:
React Router v4 - How to get current route?
React Router v4 global no match to nested route childs
TIA!
React-router doesn't give you the match params of any of the matched children Route , rather it gives you the params based on the current match. So if you have your Routes setup like
<Route path='/topic' component={Topics} />
and in Topics component you have a Route like
<Route path=`${match.url}/:topicId` component={Topic} />
Now if your url is /topic/topic1 which matched the inner Route but for the Topics component, the matched Route is still, /topic and hence has no params in it, which makes sense.
If you want to fetch params of the children Route matched in the topics component, you would need to make use of matchPath utility provided by React-router and test against the child route whose params you want to obtain
import { matchPath } from 'react-router'
render(){
const {users, flags, location } = this.props;
const match = matchPath(location.pathname, {
path: '/topic/:topicId',
exact: true,
strict: false
})
if(match) {
console.log(match.params.topicId);
}
return (
<div>
<Route exact path="/topic/:topicId" component={Topic} />
</div>
)
}
EDIT:
One method to get all the params at any level is to make use of context and update the params as and when they match in the context Provider.
You would need to create a wrapper around Route for it to work correctly, A typical example would look like
RouteWrapper.jsx
import React from "react";
import _ from "lodash";
import { matchPath } from "react-router-dom";
import { ParamContext } from "./ParamsContext";
import { withRouter, Route } from "react-router-dom";
class CustomRoute extends React.Component {
getMatchParams = props => {
const { location, path, exact, strict } = props || this.props;
const match = matchPath(location.pathname, {
path,
exact,
strict
});
if (match) {
console.log(match.params);
return match.params;
}
return {};
};
componentDidMount() {
const { updateParams } = this.props;
updateParams(this.getMatchParams());
}
componentDidUpdate(prevProps) {
const { updateParams, match } = this.props;
const currentParams = this.getMatchParams();
const prevParams = this.getMatchParams(prevProps);
if (!_.isEqual(currentParams, prevParams)) {
updateParams(match.params);
}
}
componentWillUnmount() {
const { updateParams } = this.props;
const matchParams = this.getMatchParams();
Object.keys(matchParams).forEach(k => (matchParams[k] = undefined));
updateParams(matchParams);
}
render() {
return <Route {...this.props} />;
}
}
const RouteWithRouter = withRouter(CustomRoute);
export default props => (
<ParamContext.Consumer>
{({ updateParams }) => {
return <RouteWithRouter updateParams={updateParams} {...props} />;
}}
</ParamContext.Consumer>
);
ParamsProvider.jsx
import React from "react";
import { ParamContext } from "./ParamsContext";
export default class ParamsProvider extends React.Component {
state = {
allParams: {}
};
updateParams = params => {
console.log({ params: JSON.stringify(params) });
this.setState(prevProps => ({
allParams: {
...prevProps.allParams,
...params
}
}));
};
render() {
return (
<ParamContext.Provider
value={{
allParams: this.state.allParams,
updateParams: this.updateParams
}}
>
{this.props.children}
</ParamContext.Provider>
);
}
}
Index.js
ReactDOM.render(
<BrowserRouter>
<ParamsProvider>
<App />
</ParamsProvider>
</BrowserRouter>,
document.getElementById("root")
);
Working DEMO
Try utilizing query parameters ? to allow the parent and child to access the current selected topic. Unfortunately, you will need to use the module qs because react-router-dom doesn't automatically parse queries (react-router v3 does).
Working example: https://codesandbox.io/s/my1ljx40r9
URL is structured like a concatenated string:
topic?topic=props-v-state
Then you would add to the query with &:
/topics/topic?topic=optimization&category=pure-components&subcategory=shouldComponentUpdate
✔ Uses match for Route URL handling
✔ Doesn't use this.props.location.pathname (uses this.props.location.search)
✔ Uses qs to parse location.search
✔ Does not involve hacky approaches
Topics.js
import React from "react";
import { Link, Route } from "react-router-dom";
import qs from "qs";
import Topic from "./Topic";
export default ({ match, location }) => {
const { topic } = qs.parse(location.search, {
ignoreQueryPrefix: true
});
return (
<div>
<h2>Topics</h2>
<ul>
<li>
<Link to={`${match.url}/topic?topic=rendering`}>
Rendering with React
</Link>
</li>
<li>
<Link to={`${match.url}/topic?topic=components`}>Components</Link>
</li>
<li>
<Link to={`${match.url}/topic?topic=props-v-state`}>
Props v. State
</Link>
</li>
</ul>
<h2>
Topic ID param from Topic<strong>s</strong> Components
</h2>
<h3>{topic && topic}</h3>
<Route
path={`${match.url}/:topicId`}
render={props => <Topic {...props} topic={topic} />}
/>
<Route
exact
path={match.url}
render={() => <h3>Please select a topic.</h3>}
/>
</div>
);
};
Another approach would be to create a HOC that stores params to state and children update the parent's state when its params have changed.
URL is structured like a folder tree: /topics/rendering/optimization/pure-components/shouldComponentUpdate
Working example: https://codesandbox.io/s/9joknpm9jy
✔ Uses match for Route URL handling
✔ Doesn't use this.props.location.pathname
✔ Uses lodash for object to object comparison
✔ Does not involve hacky approaches
Topics.js
import map from "lodash/map";
import React, { Fragment, Component } from "react";
import NestedRoutes from "./NestedRoutes";
import Links from "./Links";
import createPath from "./createPath";
export default class Topics extends Component {
state = {
params: "",
paths: []
};
componentDidMount = () => {
const urlPaths = [
this.props.match.url,
":topicId",
":subcategory",
":item",
":lifecycles"
];
this.setState({ paths: createPath(urlPaths) });
};
handleUrlChange = params => this.setState({ params });
showParams = params =>
!params
? null
: map(params, name => <Fragment key={name}>{name} </Fragment>);
render = () => (
<div>
<h2>Topics</h2>
<Links match={this.props.match} />
<h2>
Topic ID param from Topic<strong>s</strong> Components
</h2>
<h3>{this.state.params && this.showParams(this.state.params)}</h3>
<NestedRoutes
handleUrlChange={this.handleUrlChange}
match={this.props.match}
paths={this.state.paths}
showParams={this.showParams}
/>
</div>
);
}
NestedRoutes.js
import map from "lodash/map";
import React, { Fragment } from "react";
import { Route } from "react-router-dom";
import Topic from "./Topic";
export default ({ handleUrlChange, match, paths, showParams }) => (
<Fragment>
{map(paths, path => (
<Route
exact
key={path}
path={path}
render={props => (
<Topic
{...props}
handleUrlChange={handleUrlChange}
showParams={showParams}
/>
)}
/>
))}
<Route
exact
path={match.url}
render={() => <h3>Please select a topic.</h3>}
/>
</Fragment>
);
If you have a known set of child routes then you can use something like this:
Import {BrowserRouter as Router, Route, Switch } from 'react-router-dom'
<Router>
<Route path={`${baseUrl}/home/:expectedTag?/:expectedEvent?`} component={Parent} />
</Router>
const Parent = (props) => {
return (
<div >
<Switch>
<Route path={`${baseUrl}/home/summary`} component={ChildOne} />
<Route
path={`${baseUrl}/home/:activeTag/:activeEvent?/:activeIndex?`}
component={ChildTwo}
/>
</Switch>
<div>
)
}
In the above example Parent will get expectedTag, expectedEvent as the match params and there is no conflict with the child components and Child component will get activeTag, activeEvent, activeIndex as the parameters. Same name for params can also be used, I have tried that as well.
Try to do something like this:
<Switch>
<Route path="/auth/login/:token" render={props => <Login {...this.props} {...props}/>}/>
<Route path="/auth/login" component={Login}/>
First, the route with the parameter and after the link without parameter.
Inside my Login component I put this line of code console.log(props.match.params.token); to test and worked for me.
If you happen to use React.FC, there is a hook useRouteMatch.
For instance, parent component routes:
<div className="office-wrapper">
<div className="some-parent-stuff">
...
</div>
<div className="child-routes-wrapper">
<Switch>
<Route exact path={`/office`} component={List} />
<Route exact path={`/office/:id`} component={Alter} />
</Switch>
</div>
</div>
And in your child component:
...
import { useRouteMatch } from "react-router-dom"
...
export const Alter = (props) => {
const match = useRouteMatch()
const officeId = +match.params.id
//... rest function code
}