redirect to the same component re render - javascript

I'm using the same Form component for editing a post and adding a new one in my application. The componentDidMount of Form looks like this:
componentDidMount() {
this.props.match ? this.props.dispa({
type: 'ON_LOAD_ACTION',
payload: this.props.fetch.data.find(x => x.id == this.props.match.params.id)
}) : this.props.dispa({
type: 'ON_RESET',
payload: ''
});
}
It checks if there's an id on the URL, e.g. localhost:3000/edit/id
I'm trying to update a post. I extract the data of the post and I can fill the form with it. If there's no id on the URL I just render the form empty. The second dispatch is for resetting the state to its initial state.
I'm using react-router/redux and my problem is when I'm on the edit form and click on create form. It doesn't re-render and I got the value of the post I was in. I think that it's because i'm redirecting to the same form.
<Route exact path="/create" >
<FromProduct />
</Route>
<Route exact path="/edit/:id" component={FromProduct}></Route>
But if I click on submit button to update the post or I go to the /home first, the component re-renders perfectly.

There are different ways to see the problem:
React-router doesn't unmounts FromProduct component on each Route change. This is causing the behavior you described, you're seeing the same component always. You could try to force a re-render with an inline function.
Since your componentDidMount is not being called again, you can use componentWillReceiveProps on the FromProduct component. This way, for each Route change, it'll be executed even if it was mounted, because it'll now receive new props.
Solution #1 is not really recommended. The solution #2 would be doing something like this:
componentWillReceiveProps(newProps) {
// very similar logic for componentDidMount
// but use newProps instead of this.props
}
If you still want to try Solution #1, please check React router's documentation about inline rendering here.

Related

how to re render component on Link click [duplicate]

Is there a way to force a React-Router <Link> to load a page from path, even when the current location is already that page? I can't seem to find any mention of this in the react-router documentations.
We have a page on a route for "apply" that loads up a landing page with a hero image, some explanatory text, etc., and an "apply for this program" button that swaps in content that acts as an application form. This all happens on the same "apply" route, because users should not be able to directly navigate to this form without first hitting the landing page.
However, when they have this form open, and they click on the apply link in the nav menu again, the entire page should reload as it would on first mount, getting them "back" (but really, forward) to the landing page again.
Instead, clicking the <Link> does nothing, because react-router sees we're already on the "apply" page, and so does not unmount the current page to then mount a different one.
Is there a way to force it to unmount the current page before then mounting the requested page, even if it's for the page users are supposedly already on? (via a <Link> property for instance?)
Note: this question was posted when React-Router meant v5, and while the problem in this post is independent of a specific React-Router versions, but the solutions are not. As such, the accepted answer is the solution for React-Router v6, so if you're still using v5, first and foremost upgrade your version of React-Router, but if you absolutely can't, the accepted answer won't work for you and you'll want this answer instead.
In the Route component, specify a random key.
<Route path={YOURPATH} render={(props) => <YourComp {...props} keyProp={someValue} key={randomGen()}/>} />
when react see a different key, they will trigger rerender.
A fix I used to solve my little need around this was to change the location that React-Router looks at. If it sees a location that we're already on (as in your example) it won't do anything, but by using a location object and changing that, rather than using a plain string path, React-Router will "navigate" to the new location, even if the path looks the same.
You can do this by setting a key that's different from the current key (similar to how React's render relies on key) with a state property that allows you to write clear code around what you wanted to do:
render() {
const linkTarget = {
pathname: "/page",
key: uuid(), // we could use Math.random, but that's not guaranteed unique.
state: {
applied: true
}
};
return (
...
<Link to={linkTarget}>Page</Link>
...
);
}
Note that (confusingly) you tell the Link which values you need pass as a state object, but the link will pass those values on into the component as props. So don't make the mistake of trying to access this.state in the target component!
We can then check for this in the target component's componentDidUpdate like so:
componentDidUpdate(prevProps, prevState, snapshot) {
// Check to see if the "applied" flag got changed (NOT just "set")
if (this.props.location.state.applied && !prevProps.location.state.applied) {
// Do stuff here
}
}
Simple as:
<Route path="/my/path" render={(props) => <MyComp {...props} key={Date.now()}/>} />
Works fine for me. When targeting to the same path:
this.props.history.push("/my/path");
The page gets reloaded, even if I'm already at /my/path.
Based on official documentation for 'react-router' v6 for Link component
A is an element that lets the user navigate to another page by clicking or tapping on it. In react-router-dom, a renders an accessible element with a real href that points to the resource it's linking to. This means that things like right-clicking a work as you'd expect. You can use to skip client side routing and let the browser handle the transition normally (as if it were an ).
So you can pass reloadDocument to your <Link/> component and it will always refresh the page.
Example
<Link reloadDocument to={linkTo}> myapp.com </Link>
At least works for me!
Not a good solution because it forces a full page refresh and throws an error, but you can call forceUpdate() using an onClick handler like:
<Link onClick={this.forceUpdate} to={'/the-page'}>
Click Me
</Link>
All I can say is it works. I'm stuck in a similar issue myself and hope someone else has a better answer!
React router Link not causing component to update within nested routes
This might be a common problem and I was looking for a decent solution to have in my toolbet for next time. React-Router provides some mechanisms to know when an user tries to visit any page even the one they are already.
Reading the location.key hash, it's the perfect approach as it changes every-time the user try to navigate between any page.
componentDidUpdate (prevProps) {
if (prevProps.location.key !== this.props.location.key) {
this.setState({
isFormSubmitted: false,
})
}
}
After setting a new state, the render method is called. In the example, I set the state to default values.
Reference: A location object is never mutated so you can use it in the lifecycle hooks to determine when navigation happens
I solved this by pushing a new route into history, then replacing that route with the current route (or the route you want to refresh). This will trigger react-router to "reload" the route without refreshing the entire page.
<Link onClick={this.reloadRoute()} to={'/route-to-refresh'}>
Click Me
</Link>
let reloadRoute = () => {
router.push({ pathname: '/empty' });
router.replace({ pathname: '/route-to-refresh' });
}
React router works by using your browser history to navigate without reloading the entire page. If you force a route into the history react router will detect this and reload the route. It is important to replace the empty route so that your back button does not take you to the empty route after you push it in.
According to react-router it looks like the react router library does not support this functionality and probably never will, so you have to force the refresh in a hacky way.
I got this working in a slightly different way that #peiti-li's answer, in react-router-dom v5.1.2, because in my case, my page got stuck in an infinite render loop after attempting their solution.
Following is what I did.
<Route
path="/mypath"
render={(props) => <MyComponent key={props.location.key} />}
/>
Every time a route change happens, the location.key prop changes even if the user is on the same route already. According to react-router-dom docs:
Instead of having a new React element created for you using the
component prop, you can pass in a function to be called when the
location matches. The render prop function has access to all the same
route props (match, location and history) as the component render
prop.
This means that we can use the props.location.key to obtain the changing key when a route change happens. Passing this to the component will make the component re-render every time the key changes.
I found a simple solution.
<BrowserRouter forceRefresh />
This forces a refresh when any links are clicked on. Unfortunately, it is global, so you can't specify which links/pages to refresh only.
From the documentation:
If true the router will use full page refreshes on page navigation. You may want to use this to imitate the way a traditional server-rendered app would work with full page refreshes between page navigation.
Here's a hacky solution that doesn't require updating any downstream components or updating a lot of routes. I really dislike it as I feel like there should be something in react-router that handles this for me.
Basically, if the link is for the current page then on click...
Wait until after the current execution.
Replace the history with /refresh?url=<your url to refresh>.
Have your switch listen for a /refresh route, then have it redirect back to the url specified in the url query parameter.
Code
First in my link component:
function MenuLink({ to, children }) {
const location = useLocation();
const history = useHistory();
const isCurrentPage = () => location.pathname === to;
const handler = isCurrentPage() ? () => {
setTimeout(() => {
if (isCurrentPage()) {
history.replace("/refresh?url=" + encodeURIComponent(to))
}
}, 0);
} : undefined;
return <Link to={to} onClick={handler}>{children}</Link>;
}
Then in my switch:
<Switch>
<Route path="/refresh" render={() => <Redirect to={parseQueryString().url ?? "/"} />} />
{/* ...rest of routes go here... */}
<Switch>
...where parseQueryString() is a function I wrote for getting the query parameters.
There is a much easier way now to achieve this, with the reloadDocument Link prop:
<Link to={linkTarget} reloadDocument={true}>Page</Link>
you can use BrowserRouter forceRefresh={true}
I use react-router-dom 5
Example :
<BrowserRouter forceRefresh={true}>
<Link
to={{pathname: '/otherPage', state: {data: data}}}>
</Link>
</BrowserRouter>
Solved using the Rachita Bansal answer but with the componentDidUpdate instead componentWillReceiveProps
componentDidUpdate(prevProps) {
if (prevProps.location.pathname !== this.props.location.pathname) { window.location.reload();
}
}
You can use the lifecycle method - componentWillReceiveProps
When you click on the link, the key of the location props is updated. So, you can do a workaround, something like below,
/**
* #param {object} nextProps new properties
*/
componentWillReceiveProps = (nextProps)=> {
if (nextProps.location.pathname !== this.props.location.pathname) {
window.location.reload();
}
};
To be honest, none of these are really "thinking React". For those that land on this question, a better alternative that accomplishes the same task is to use component state.
Set the state on the routed component to a boolean or something that you can track:
this.state = {
isLandingPage: true // or some other tracking value
};
When you want to go to the next route, just update the state and have your render method load in the desired component.
Try just using an anchor tag a href link. Use target="_self" in the tag to force the page to rerender fully.

Does React Router necessarily complicate state management (without Redux)?

I'm fairly new to React to trying to wrap my head around routing via React Router while also passing required data to components. I will probably eventually incorporate Redux in my app, but I'm trying to avoid it initially.
It seems like using React Router as opposed to serving individual pages from the server means having to store state data in the App.js component since that's where the Router exists.
For example if I'm on site.com/x and I want to navigate to site.com/y and /x looks like this:
<div>
<XOuter >
<XInner />
</XOuter>
</div>
And App.js looks like this:
<BrowserRouter>
<Route exact path="/x" component={X} />
<Route exact path="/y" component={Y} />
</BrowserRouter>
... if the GET request is being called from XInner and the results will inform the content of /y, XInner will have to pass the response all the way back to App.js to properly render /y.
It seems like this could get messy quickly. Is there any way to avoid it?
This isn't as bad as you think, for two reasons:
If you use React Router's <Link> component to create links instead of using <a> directly, it will add event handlers that cancel the link's actual navigation and instead use history.pushState to do the navigation. To the user, they think they're on the new page (the URL bar shows this), but no GET request ever actually happened to load it.
React Router's paths are parsed via path-to-regexp. This lets you add parameters to the URL and then extract them from the router's props. You can also put data in the query string and then parse it later. This will let you pass state from one page to another without using any top-level React state, with the added benefit of making the browser's history and URL copying automatically work right.
The data is stored in the path instead of App.js. Path should be converted to props through pure function so the same path is always converted to the same props. That's the external state that chooses a <Route /> and sets its props.
Root of your problems lies in this design:
if the GET request is being called from XInner and the results will inform the content of /y, XInner will have to pass the response all the way back to App.js to properly render /y
Remove the if the GET request is being called from XInner... and all your concerns become moot.
Component A should not be responsible for fetching data for Component B. If /y needs data, fetch the data in Y's componentdidmount.
Example code showing the concept
fetchData(){
fetch(...) // or axios or whatever
.then(() => {
this.setState({
data: 'Hello World'
})
})
}
componentDidMount(){
this.fetchData()
}
render() {
return(
<div>
{this.state.data}
</div>
)
}

React-Router not unmounting on location parameter change

This problem is driving me insane, I got a simple little app created by create-react-app and I am using React-Router.
JSX:
<Router>
<Route path="/pages/:pageId" component={Page} />
</Router>
In the Page component I have an fetch on componentDidMount, its working as expected first time the route is loaded.
For example I visit: /pages/13 and then it fetches that pages data, but when I am on: /pages/13 and then click on a Link component (imported from React-Router) redirecting me to: /pages/15 - the pageId prop is then updated but it never re-renders.
The Page component never run componentWillUnmount before, or componentDidMount after.
Expected behavior:
Visit: /pages/13 → render() → componentDidMount() → render()
Click on Link component /pages/15 → componentWillUnmount() → render()
→ componentDidMount() → render()
I am using the following versions:
react: 16.3.2
react-dom: 16.3.2
react-router-dom: 4.2.2
What am I doing wrong? I am still pretty new to React so be nice :)
Your problem is that componentDidMount only executes when the component is completely mounted, and this only occurs one time. In this case, changing the route param doesn't change the component, I mean, you still being in the same component when you change the pageId, thus the componentDidMount is never executed again.
What could you do then?, well, I suggest you to look into componentWillReceiveProps(newProps) method, this is executed whenever the component's props are about to be modified, which in this case, is what you are looking for, because, according to this:
You’ll have access match objects in various places:
Route component as this.props.match;
Route render as ({ match }) => ();
Route children as ({ match }) => ();
withRouter as this.props.match;
matchPath as the return value;
the match object (which contains the route params) is given through component's props.
So, short answer. Use componentDidMount for first time fetching, and then use componentWillRecieveProps(newProps) for all the rest fetching calls.
check this for more info.
Note: I didn't know that componentWillRecieveProps(newProps) was about to be somewhat deprecated, anyways, it suggest you to use getDerivedStateFromProps(nextProps, prevState) which is basically the same
When parameter is changing, your Route doesn't remount your component. This is an expected behaviour. You should catch the parameter changing via componentWillReceiveProps, otherwise if you wish to force remounting, you should use <Route path="/your/path/with/:id" render={props => <Component {...props} key={props.params.id} />

When in the React component life cycle can I execute a route change?

I have some kind of a wizard where each step has it's own route. Now when a user uses a direct link to the second step route, I would like to redirect him to the first step (using browserHistory.replace).
The problem I face is that I don't really know which stage in the components life cycle it should be performed. I have tried constructor, render, componentWillMount, but all of those do not prevent the component from rendering even if I use router. So what happens is that redirect occurs, but the component from the previous route still gets renders and fails (no data obviously).
Is there any "proper" way of redirecting during the component initialization (I need to check the state)? Or is there any other better way of doing so?
I don't know the "official" recommended way (still interested if someone can find it), but what worked for me is this:
Redirect during componentWillMount
During render use the same condition as in componentWillMount to return null
Example:
class MyComponent extends Component {
componentWillMount() {
if (!this.props.data) {
browserHistory.replace(myRoute);
}
}
render() {
if (this.props.data) {
return (
<div>
...
</div>
);
}
return null;
}
}
In v2/3 you should use the onEnter function to redirect (using the replace function). v2/3 replicates most of React's life cycle functions because it doesn't really use React to render route components. That is to say, <Route>s are just used for configuration and react-router generates an array of components for a given route and renders each individually.
function redirectToStart(nextState, replace) {
if (!nextState.someCondition) {
replace('/initial-page')
}
}
<Route onEnter={redirectToStart} ... />

React Router Query Parameters

I have a React application which is using react-router v2.4. I have a route defined like so:
<Router history={this.props.history}>
<Route path="/:organisationId/objects"
component={ObjectsPage}
onEnter={(state) => {
this.props.dispatch(objectsFetch(
state.params.organisationId,
state.location.query
));
}}
/>
</Router>
Essentially, this route dispatches an action to fetch some objects from an API which are then rendered in a tabular format. I would like this table to be searchable, sortable and paginated and I think it would be appropriate to store the state of the table in the URL as query parameters so it can be refreshed and browser back/forward functionality isn't broken.
In order to update my table component I make a call to browserHistory with a URI similar to this (note the query parameters):
browserHistory.push('/0f08ac61-ddbd-4c73-a044-e71b8dd11edc/objects?page=2&search=query&sort=firstname|desc');
However, this doesn't trigger react-router into thinking the route has updated as the onEnter callback is never fired even though the browser history is updated with the new query string. I think I understand why this is happening; since the query string isn't part of the defined route I guess the package won't pick the change up.
Is there a way to use react-router with query parameters like this or will I have to make my filters part of the URI?
Need to use onChange in the route definition - onEnter is called the first time you hit a route and onChange is called when the route status changes:
<Route path="/:organisationId/patients"
component={PatientsPage}
onEnter={(state) => {
this.props.dispatch(patientsFetch(
state.params.organisationId,
state.location.query
));
}}
onChange={(state) => {
this.props.dispatch(patientsFetch(
state.params.organisationId,
state.location.query
));
}}
/>

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