I'm trying to display articles filtered by subject. When you access directly path="/subject/:selectedSubject" (subject/TECH) for example it works perfectly. However if you navigate through <Link to={"/subject/TECH"} /> it will change the URL but will not load new articles.
I've tried: connecting everything with "withRouter".
I know that the <Link/> is changing the redux state, however that is not calling componentWillMount() which is where fetchArticles() is.
So, my question is, where should I put fetchArticles in order for it to be called when is triggered. I tried putting it inside render() but it keeps getting called non-stop. Or maybe I'm approaching this the wrong way.
PS: if another path gets called via <Link/>, like for example path="/", it works as intended (loads up new articles).
at App/
<BrowserRouter>
<div>
<Route path="/" exact component={ArticlesList} />
<Route path="/subject/:selectedSubject" component={ArticlesList} />
</div>
</BrowserRouter>
at ArticleList/
componentDidMount() {
if (this.props.match.params.selectedSubject) {
const selectedSubject = this.props.match.params.selectedSubject.toUpperCase();
this.props.fetchArticles(selectedSubject);
} else {
this.props.fetchArticles();
}
}
at Link/
{this.props.subjects.map(subject => {
return (
<Link to={`/subject/${subject.name}`} key={subject.name}>
<li>
<span>{subject.name}</span>
</li>
</Link>
);
})}
Since you use the same Component for / and /subject/:selectedSubject, he's not calling mounting lifecycle methods, including constructor() and componentDidMount().
You have to use updating lifecycle method, especially componentDidUpdate() to handle a update of your component.
Related
I have a page where i add products to a product list. After a successful add, the app needs to go back to the list to see the products again with the new entry added. The redirecting to the product list works fine, and i see the products again, but the new product is not on the list. In order to view the new added products, i have to hard reload the page. For some reason the component is not getting re-rendered thus not requesting the new product list from the server.
Why is this happening? How can I make the ProductPage re-render without forcing a full app refresh.
I have reproduced the problem in this codesandbox.
This was pretty much covered by Jacob Smith in his above comment. However, to expand a little upon his explanation, you have a setup that looks something like this:
// App.jsx
return (
<>
<h1>Some header</h1>
<Switch>
<Route path='productlist' component={ProductList} />
</Switch>
</>
)
// ProductList.jsx
const [state, setState] = usetState();
useEffect(() => {
loadSomeData().then(data => {
setState(data);
})
}, []);
return (
<>
<Switch>
<Route path='productlist' render={() => <ProductPage data={state} />} />
<Route path='productlist/add' component={AddProduct} />
</Switch>
</>
)
Due to this data flow, new data is only loaded when ProductList mounts, unmounts, and mounts again. However, nothing you do in either ProductPage or AddProduct ever unmounts ProductList, since both are rendered in that component.
This can be fixed in two main ways, move the render of AddProduct to the top level in App.jsx or, if Axios.post returns the new data, you can hand down the state setting method to AddProduct and set the state in the .then callback, since the parent component is not unmounted.
Another way is that you should really hard reload after the submitting the form by adding the following code at the end of the form submit handler function of your form.
window.location = '/productList';
I am seeking to recreate a pattern with React Router. It is best described by the Twitter example: as you hit the Tweet button, the browser navigates to /compose/tweet, mounting the composer component. However, and that's the key, the previous route (/home, /explore, /notifications, /messages) is kept mounted despite the route change. How do you do that?
This could be called bidimensional routing: the /compose/tweet route is kept orthogonal with respect to the other routes that render the main view. The other routes are hidden (i.e., not in the address bar any longer) upon navigating to /compose/tweet, thereby rendering two independent routes (say, /notifications and /compose/tweet) at once.
My actual example: I need to show a user settings menu (/user/menu) as a large sidebar, but I do not want that to change whether the user was navigating / (the homepage), /faq, /contact, etc. Based on my current understanding of React Router, as soon as you hit /user/menu, any other route (take /faq as an example) would be unmounted based on route match.
Caching the previous route (e.g., Redux, which I'm using extensively already) does not seem feasible, since, even though I would be able to redirect the user to the previous route upon exiting /user/menu, React would still be unmounting components, in fact showing the homepage in the background until the user exits /user/menu & gets redirected to where they were at, which is not the intended behaviour. I would want the rest of the page to stay there with the rendered components, just the way Twitter does.
Am I overlooking anything? Is this an easy pattern and I am missing something?
Note: it's a SSR isomorphic app, but I guess/hope that won't change things.
Despite Adam Abramov's suggestion to keep React Router as the source of truth for whatever can be passed as route, and avoid deep integrations between Router and Redux, I found myself having to use Redux as the main source of truth in this (important) use case. I still wanted to have Route components for SSR and SEO purposes.
So, I created my own MultidimensionalSwitch and MultidimensionalRoute components to solve this use case. If a MultidimensionalSwitch is mounted, it will render the components at their subroutes, but if none of them is matched, it will render them based on another dimension, which is provided by Redux at an additional alt property of the corresponding MultidimensionalRoute.
Here below is some code, feel free to answer/ask should you need more info about it.
Main
class _Main extends Component {
render() {
const {menuOpen,selected} = this.props;
return (
<Fragment>
<Route exact path={exactRoutes.ROOT} component={() => <Redirect to={selected?exactRoutes[selected]:exactRoutes.HOME} />} />
<Header />
<Route path={nestedRoutes.AUTH+routeParams.LOGIN_SIGNUP.key} component={ScreenAuth} />
<Route path={exactRoutes.USER_MENU} component={ScreenUser} />
{!menuOpen?"":<ScreenMenu />}
<ScreenMain>
<MultidimensionalSwitch>
<MultidimensionalRoute path={exactRoutes.HOME} alt={selected===guestMenuOption.HOME} component={GuestHome} />
<MultidimensionalRoute path={exactRoutes.USER} alt={selected===guestMenuOption.USER} component={User} />
<MultidimensionalRoute path={exactRoutes.VISION} alt={selected===guestMenuOption.VISION} component={GuestVision} />
<MultidimensionalRoute path={exactRoutes.FAQ} alt={selected===guestMenuOption.FAQ} component={GuestFaq} />
<MultidimensionalRoute path={exactRoutes.INFOGRAPHICS} alt={selected===guestMenuOption.INFOGRAPHICS} component={GuestInfographics} />
<MultidimensionalRoute path={exactRoutes.BLOG} alt={selected===guestMenuOption.BLOG} component={GuestBlog} />
<MultidimensionalRoute path={exactRoutes.CONTACT} alt={selected===guestMenuOption.CONTACT} component={GuestContact} />
</MultidimensionalSwitch>
<Footer />
</ScreenMain>
<Flare />
</Fragment>
);
};
}
const mapStateToProps = state => ({
menuOpen: state.client.guest.menuOpen,
selected: state.client.guest.guestMenuOption,
});
const Main = withRouter(connect(mapStateToProps,{})(_Main));
export default Main;
MultidimensionalSwitch
class _MultidimensionalSwitch extends Component {
render() {
return (
<Fragment>
<Switch>
{this.props.children}
{this.props.children.map(child => !child.props.alt?"":<Route path={nestedRoutes.ROOT} component={child.props.component} />)}
</Switch>
</Fragment>
);
}
}
const mapStateToProps = state => ({
selected: state.client.guest.guestMenuOption,
});
const MultidimensionalSwitch = withRouter(connect(mapStateToProps,{})(_MultidimensionalSwitch));
export default MultidimensionalSwitch;
MultidimensionalRoute
class _MultidimensionalRoute extends Component {
render() {
const {path,component} = this.props;
return (
<Fragment>
<Route exact path={path} component={component} />
</Fragment>
);
}
}
const mapStateToProps = (state,ownProps) => ({
path: ownProps.path,
component: ownProps.component,
});
const MultidimensionalRoute = withRouter(connect(mapStateToProps,{})(_MultidimensionalRoute));
export default MultidimensionalRoute;
I am using Ant design breadcrumbs. I am trying to change the page using link and pushing the URL, I can see the URL change but the page in not changing.
I tried using Link, then creating a function for onClick but everything just change the URL.
Route:
<Route exact path="/assistant/:wId/skill/xyz/:sid" component={ xyz } />
Tried process 1:
<Breadcrumb separator=">">
<Breadcrumb.Item
onClick={this.redirectToParam2}>
{param2}
</Breadcrumb.Item>
</Breadcrumb>
redirectToParam2 = () => {
this.props.history.push(`/assistant/${wId}/skill/xyz/${sId}`);
}
Tried process 2:
<Breadcrumb separator=">">
<Breadcrumb.Item>
<Link to= {`/assistant/${wId}/skill/xyz/${sId}`}>
{param2}
</Link>
</Breadcrumb.Item>
</Breadcrumb>
Even I tried without the Breadcrumbs component but it's still not changing the page.
I want the page to change as soon as the URL changes.
Thank you in advance.
Try this,
import { Link } from "react-router-dom";
<Breadcrumb separator=">">
<Breadcrumb.Item>
<Link to= {`/assistant/${wId}/skill/xyz/${sId}`}>
{param2}
</Link>
</Breadcrumb.Item>
</Breadcrumb>
The problem you are running into, is that with changing the parameters used as props for the xyz component, the component is not replaced but gets new properties. Since nothing changes, i'm assuming you have state that gets filled either in the constructor or ComponentWillMount/ComponentDidMount.
React class components have a lifecycle function for this: componentDidUpdate.
componentDidUpdate() is invoked immediately after updating occurs. This method is not called for the initial render.
Use this as an opportunity to operate on the DOM when the component has been updated. This is also a good place to do network requests as long as you compare the current props to previous props (e.g. a network request may not be necessary if the props have not changed).
Quote from react docs, See: https://reactjs.org/docs/react-component.html#componentdidupdate
componentDidUpdate(prevProps) {
if ((this.props.params.match.sid !== prevProps.params.match.sid) ||
(this.props.params.match.wid !== prevProps.params.match.wid)) {
this.populateState(this.props.params.match); //fill your state
}
}
I have a question regarding component loading in React.js.
Is there a way to load components in a specific order. For instance I have the components for each page of my single page website.
I would like <homepage /> and it's images to load first than <profile />, then <works />, and so on...
The idea being that when a user first visit my site, homepage will load instantly(or really quickly) and the rest can follow so at least the user has something to look at before they potentially start scrolling.
I've tried to google "loading components in order with react.js" but no luck.
class MainContent extends React.Component {
componentDidMount() {
console.log("component mounted");
}
render() {
return(
<div className="main-content">
<ul className="block">
<HomePage />
<ProfilePage />
<WorksPage />
<ContactPage />
<BlogPage />
</ul>
</div>
)
}
}
My first idea would be to have a promise in <componentDidMount /> function which would switch a boolean state to true when <Homepage /> is loaded.
<Homepage />
{
this.state.loaded ?
<ProfilePage />
<WorksPage />
<ContactPage />
<BlogPage />
:
null
;
}
Am I on the right track with that train of thought?
Any help is much appreciated.
Thanks,
Moe
You are doing just fine. It is a recommended approach:
componentDidMount() is invoked immediately after a component is
mounted. Initialization that requires DOM nodes should go here. If you
need to load data from a remote endpoint, this is a good place to
instantiate the network request. Setting state in this method will
trigger a re-rendering.
So initially in render method render only portions on UI that are immediately available. then in componentDidMount - fire and wait for completion of your promise to fetch the rest of the data, and afterwards call setState to refresh UI to show in full.
I have a container component with a modal in it that is opened and closed based on a state property.
I want to control this via the URL, i.e. I want to have
/projects - the modal is NOT open
/projects/add - the modal IS open
As well as being able to link directly to it, I want the URL to change when I click on links within the main container to open the modal.
Can someone explain how I could do this, or point me in the right direction of a good tutorial?
NOTE: This way is not perfect. Even more it's rather antipattern than pattern. The reason I publish it here is it works fine for me and I like the way I can add modals (I can add modal to any page and in general their components don't depends on the other app in any way. And I keep nice url's instead of ugly ?modal=login-form). But be ready to get problems before you find everything working. Think twice!
Let's consider you want following url's:
/users to show <Users /> component
/users/login to show <Users /> component and <Login /> modal over it
You want Login to not depend on Users in anyway, say adding login modal to other pages without pain.
Let's consider you have kinda root component which stands on top of other components. For example Users render may look something like this:
render() {
return (
<Layout>
<UsersList />
</Layout>
);
}
And Layout's render may look something like this:
render() {
return (
<div className="page-wrapper">
<Header />
<Content>
{this.props.children}
</Content>
<Footer />
</div>
);
}
The trick is to force modal's injection to <Layout /> every time we need it.
The most simple approach is to use flux for it. I'm using redux and have ui reducer for such page meta-information, you can create ui store if you use other flux implementation. Anyway, final goal is to render modal if <Layout />'s state (or even better props) contains modal equal to some string representing modal name. Something like:
render() {
return (
<div className="page-wrapper">
<Header />
<Content>
{this.props.children}
</Content>
{this.props.modal ?
<Modal key={this.props.modal} /> :
null
}
<Footer />
</div>
);
}
<Modal /> returns modal component depends on given key (In case of our login-form key we want to receive <Login /> component).
Okay, let's go to router. Consider following code snippet.
const modal = (key) => {
return class extends React.Component {
static displayName = "ModalWrapper";
componentWillMount() {
// this is redux code that adds modal to ui store. Replace it with your's flux
store.dispatch(uiActions.setModal(key));
}
componentWillUnmount() {
store.dispatch(uiActions.unsetModal());
}
render() {
return (
<div className="Next">{this.props.children}</div>
);
}
}
};
...
<Route path="users" component={Next}>
<IndexRoute component={Users}>
<Route path="login" component={modal('login-form')}>
<IndexRoute component={Users} />
</Route>
</Route>
(Don't care about Next - I add it here for simplicity. Imagine it just renders this.props.children)
modal() function returns react component that triggers change in ui store. So as soon as router gets /users/login it adds login-form to ui store, <Layout /> get it as prop (or state) and renders <Modal /> which renders corresponding for given key modal.
To programmatically assess to a new URL, pass the router to your component and use push. push for example will be call in the callback trigger by the user action.
When setting your router set a route to /projects/:status. then, in your component route, you can read the value of status using this.props.param.status. Read "whats-it-look-lik" from react-router for an example.