I have a project that needs to show a register modal when the user is null,
it works some times??
I am asking a state element if user exists, then showing the modal, the problem is that when the user is logged in, when the page is shown, sometimes it shows the register modal,
like it renders and then checks if user === null
Is that my problem?
NOTE: on other tabs, this works fine, like it had more time to load the state?
const mapStateToProps = ({ firebase, navigation }) => ({
firebase,
})
function Feed ({ feed, firebase }) {
React.useEffect(
() => navigation.addListener('focus', () =>
{
console.log("aki:: ",firebase.user)
if (firebase.user === null) {
//SHOW MODAL TO INVITE REGISTER
setVisible(true),
navigation.dispatch(navigateToBrowse())
} else {
setVisible(false)
}
}
),
[]
);
It's likely because the firebase.user prop isn't set before this component is rendered. It's impossible to tell without seeing the parent component.
You can block the tree from rendering until firebase.user exists.
Otherwise, you have to differentiate between 1. auth is loading, 2. auth is done loading and user doesn't exist, and 3. auth is done loading and user exists.
I initially thought it was because of how you were handling the navigation side effect, so here's that code anyways:
function Feed({ feed, firebase }) {
const [visible, setVisible] = useState<boolean>(false);
React.useEffect(() => {
const checkForUser = () => {
setVisible(firebase.user === null);
}
// Check for user on all focus events
navigation.addListener('focus', checkForUser);
// Also check for user immediately
checkForUser();
}, []);
React.useEffect(() => {
// Only navigate away when visible gets turned on
if (visible) navigation.dispatch(navigateToBrowse());
}, [visible])
}
Related
My code is not long or complicated at all. It's simple. so please read!
(Im using react + next.js)
In the root file, app.js, I have useEffect to fetch photo data. This data array will be used in a page component so I pass it down from app.js via <Component.../>
function MyApp({ Component, pageProps }) {
const [photoData, setPhotoData] = useState([]);
const [user, setUser] = useState([]);
useEffect(() => {
const getPhotos = async () => {
try {
const photoData = await axios.get(
"https://jsonplaceholder.typicode.com/albums"
);
setPhotoData(photoData.data);
} catch (error) {
console.log(error);
}
};
getPhotos();
}, []);
useEffect(() => {
//code for finding user. no external api used.
setUser(user);
}
}
}, []);
const passedProps = {
...pageProps,
photoData,
user
};
return (
...
<Component {...passedProps} />
)
Then I pass the data (photodata) from a Home component to a (app.js 's) grandchild component, an Photo component
export default function Home({ photoData, user }) {
return(
<Photo photoData={photoData} user={user} />
)
In Photo component, I am receiving photoData and trying to set a state for photoArr with the default state of photoData.
When the entire app is first loaded, the photoData is passed down to the Photo component successfully that it sets the state without any issue.
But the main problem is that when I am in the Photo page (photos are loaded) and refresh the page, then it does not set the state for photoArr with photoData. Even though I can console log photoData received from app.js, it does not set state, photoArr, with the default state, photoData.
export default function Photo({ photoData, user }) {
const [photoArr, setPhotoArr] = useState(photoData);
//I have this as state because I change this array
//later on in this component (doing CRUD on the photo array).
console.log(photoData); // this returns the array received from app.js
console.log(photoArr); // []. returns an empty array
console.log(user); // returns the user object received from app.js.
return (
<div>
{photoArr.length > 0 ?
.... code mapping photoArr
: "Data is empty" //It returns this comment when I refresh the page
}
</div>
)
As you can see above, when I refresh the page, I get "Data is empty" meaning photoArr was not set even with the given default state. If I keep refreshing the page multiple times, it still shows a blank page.
From my research, it's due to setting state being asynchronous? So then how can I fix this problem?
Try this:
(In your Photo page)
const [photoArr, setPhotoArr] = useState(null);
useEffect(() => {
if(photoData.length) setPhotoArr(photoData) // If not empty, set the Arr
},[photoData]} // We listen to photoData's change
On page load, there aren't any data in your photoData, and as it pass down to Photo component, react remembers that state.
But with useEffect listen to photoData's change, we can setPhotoArr once the getPhotos function got the data back.
I am new to react and am having trouble figuring out why the data inside my Content component does not re-render on refresh.
When I visit one of the routes, say /sentences-of-the-day, and then I refresh the page, it seems all the stuff inside content is gone.
Can someone please help me out?
Here is the code sandbox:
https://codesandbox.io/s/mainichome-v7hrq
You need to load the data once the component is mounted (using useEffect) set to local state to trigger the render. In each refresh, mounting happens again and you have the data after each refresh.
Define another function in content.data.js
export const getContentData = () => {
return Promise.all(contentDataStories.map((func) => func()));
};
In your content.component.jsx
import { getContentData } from "./content.data.js";
const [content, setContent] = useState([]);
useEffect(() => {
(async () => {
setContent(await getContentData());
})();
}, []);
Code sandbox => https://codesandbox.io/s/mainichome-forked-4sx5n?file=/src/components/content/content.component.jsx:302-449
The problem is here:
import contentData from "./content.data.js";
//...
const [content] = useState(contentData);
That imports contentData and then sets it as state.
However, that value is asynchronous.
const contentData = [];
contentDataStories.forEach(function (func) {
func().then((json) => {
contentData.push(json);
});
});
export default contentData;
It's just [] until those promises reoslve.
So what's happening is that the page is loading fine, but the content from that file hasn't loaded before the first render.
This is a race condition. Which will happen first, the data loading or the render? Sometimes the render wins and everything is fine, but sometimes it doesn't and you get a blank page.
To fix it, you need to make React aware of your data loading, so that it can re-render when the data finishes loading.
First make a function that does your async loading:
export function getContentData() {
return new Promise((resolve) => {
// fetch async stuff here
resolve(myDataHere)
})
}
And then call that from a useEffect, which sets the state.
function Content() {
const { titleParam } = useParams();
const [content, setContent] = useState(contentData);
useEffect(() => {
getContentData().then(setContent);
}, [getContentData]);
//...
}
Now when you component mounts, it calls getContentData. And then that promise resolves, it sets the state, triggering a a new render.
On an app I'm working on, I have to change the language of the app based on what the user chose. I have one language selector for non-registered users and another one for registered users.
The code for the selector looks like this
const LanguageSelect: React.FunctionComponent<Props> = (props: Props) => {
const language = useLanguage();
const currentUser = useCurrentUser();
const { updateUser } = props;
const updateLanguage = useCallback((currentUser, language) => {
updateUser(currentUser.set('language', language));
}, [currentUser, language]);
useEffect(() => {
if (currentUser != null) {
try {
updateLanguage(currentUser, language);
} catch (error) {
console.log(error.message);
}
}
}, [language, currentUser, updateLanguage]);
return (
<Select
background={Color.minimalWhite}
useBorderRadius={true}
onValueChange={props.setLocalizationFunction}
items={languageDictionary}
value={languageDictionary.find((lan) => lan.value === language).label}
/>
);
}
The problem is that when a user selects a language when they're not logged in, and then has another language selected when they're logged in (for example, first they select english when not logged in, then french when they're logged in), when the Home screen for a logged in user is rendered, it gets re-rendered almost immediately. I don't know what's going on, I even tried all kinds of stuff to make the useEffect on the languageSelector to run only once, however, the screen gets re-rendered all the time. How can I make the useEffect to run only once whenever the user gets logged in or they change the language by themselves to prevent automatic re-rendering?
If I've got a function that creates a confirm popup when you click the back button, I want to save the state before navigating back to the search page. The order is a bit odd, there's a search page, then a submit form page, and the summary page. I have replace set to true in the reach router so when I click back on the summary page it goes to the search page. I want to preserve the history and pass the state of the submitted data into history, so when I click forward it goes back to the page without error.
I've looked up a bunch of guides and went through some of the docs, I think I've got a good idea of how to build this, but in this component we're destructuring props, so how do I pass those into the state variable of history?
export const BaseSummary = ({successState, children}: BaseSummaryProps) => {
let ref = createRef();
const [pdf, setPdf] = useState<any>();
const [finishStatus, setfinishStatus] = useState(false);
const onBackButtonEvent = (e) => {
e.preventDefault();
if (!finishStatus) {
if (window.confirm("Your claim has been submitted, would you like to exit before getting additional claim information?")) {
setfinishStatus(true);
props.history.push(ASSOCIATE_POLICY_SEARCH_ROUTE); // HERE
} else {
window.history.pushState({state: {successState: successState}}, "", window.location.pathname);
setfinishStatus(false);
}
}
};
useEffect(() => {
window.history.pushState(null, "", window.location.pathname);
window.addEventListener('popstate', onBackButtonEvent);
return () => {
window.removeEventListener('popstate', onBackButtonEvent);
};
}, []);
Also I'm not passing in the children var because history does not clone html elements, I just want to pass in the form data that's returned for this component to render the information accordingly
first of all, I think you need to use "useHistory" to handling your hsitry direct without do a lot of complex condition, and you can check more from here
for example:
let history = useHistory();
function handleClick() {
history.push("/home");
}
now, if you need to pass your history via props in this way or via your code, just put it in function and pass function its self, then when you destruct you just need to write your function name...for example:
function handleClick() {
history.push("/home");
}
<MyComponent onClick={handleClick} />
const MyComponent = ({onClick}) => {....}
I fixed it. We're using reach router, so everytime we navigate in our submit forms pages, we use the replace function like so: {replace: true, state: {...stateprops}}. Then I created a common component that overrides the back button functionality, resetting the history stack every time i click back, and using preventdefault to stop it from reloading the page. Then I created a variable to determine whether the window.confirm was pressed, and when it is, I then call history.back().
In some scenarios where we went to external pages outside of the reach router where replace doesn't work, I just used window.history.replaceStack() before the navigate (which is what reach router is essentially doing with their call).
Anyways you wrap this component around wherever you want the back button behavior popup to take effect, and pass in the successState (whatever props you're passing into the current page you're on) in the backButtonBehavior function.
Here is my code:
import React, {useEffect, ReactElement} from 'react';
import { StateProps } from '../Summary/types';
export interface BackButtonBehaviorProps {
children: ReactElement;
successState: StateProps;
}
let isTheBackButtonPressed = false;
export const BackButtonBehavior = ({successState, children}: BackButtonBehaviorProps) => {
const onBackButtonEvent = (e: { preventDefault: () => void; }) => {
e.preventDefault();
if (!isTheBackButtonPressed) {
if (window.confirm("Your claim has been submitted, would you like to exit before getting additional claim information?")) {
isTheBackButtonPressed = true;
window.history.back();
} else {
isTheBackButtonPressed = false;
window.history.pushState({successState: successState}, "success page", window.location.pathname); // When you click back (this refreshes the current instance)
}
} else {
isTheBackButtonPressed = false;
}
};
useEffect(() => {
window.history.pushState(null, "", window.location.pathname);
window.addEventListener('popstate', onBackButtonEvent);
return () => {
window.removeEventListener('popstate', onBackButtonEvent);
};
}, []);
return (children);
};
I am developing an app named "GitHub Finder".
I am fetching the date in App component using async function and pass these function to User component as props and I call these functions in useEffect.
The problem is here, when I goto user page for second time it shows previous data which I passed in props from App component and then it shows loader and shows new data.
Here is App component code where I am fetching date from APIs and passing to User component through props.
// Get single GitHub user
const getUser = async (username) => {
setLoading(true);
const res = await axios.get(
`https://api.github.com/users/${username}?client_id=${
process.env.REACT_APP_GITHUB_CLIENT_ID}&client_secret=${
process.env.REACT_APP_GITHUB_CLIENT_SECRET}`
);
setUser(res.data);
setLoading(false);
}
// Get user repos
const getUserRepos = async (username) => {
setLoading(true);
const res = await axios.get(
`https://api.github.com/users/${username}/repos?
per_page=5&sort=created:asc&client_id=${
process.env.REACT_APP_GITHUB_CLIENT_ID}&client_secret=${
process.env.REACT_APP_GITHUB_CLIENT_SECRET}`
);
setRepos(res.data);
setLoading(false);
}`
User component code.
useEffect(() => {
getUser(match.params.login);
getUserRepos(match.params.login);
// eslint-disable-next-line
}, []);
I've recorded a video, so you guys can easily understand what I am trying to say.
Video link
Check live app
How can I solve this problem?
Thank in advance!
Here is what happens in the app :
When the App component is rendered the first time, the state is user={} and loading=false
When you click on a user, the User component is rendered with props user={} and loading=false, so no spinner is shown and no data.
After the User component is mounted, the useEffect hooks is triggered, getUser is called and set loading=true (spinner is shown) then we get the user data user=user1 and set loading=false (now the user data is rendered)
When you go back to search page, the app state is still user=user1 and loading=false
Now when you click on another user, the User component is rendered with props user=user1 and loading=false, so no spinner is shown and the data from previous user is rendered.
After the User component is mounted, the useEffect hooks is triggered, getUser is called and set loading=true (spinner is shown) then we get the user data user=user2 and set loading=false (now the new user data is rendered)
One possible way to fix this problem :
instead of using the loading boolean for the User component, inverse it and use loaded
When the User component is unmounted clear the user data and the loaded boolean.
App component:
const [userLoaded, setUserLoaded] = useState(false);
const getUser = async username => {
await setUserLoaded(false);
const res = await axios.get(
`https://api.github.com/users/${username}?client_id=${
process.env.REACT_APP_GITHUB_CLIENT_ID
}&client_secret=${process.env.REACT_APP_GITHUB_CLIENT_SECRET}`
);
await setUser(res.data);
setUserLoaded(true);
};
const clearUser = () => {
setUserLoaded(false);
setUser({});
};
<User
{...props}
getUser={getUser}
getUserRepos={getUserRepos}
repos={repos}
user={user}
loaded={userLoaded}
clearUser={clearUser}
/>
User component:
useEffect(() => {
getUser(match.params.login);
getUserRepos(match.params.login);
// eslint-disable-next-line
return () => clearUser();
}, []);
if (!loaded) return <Spinner />;
You can find the complete code here
Please make your setUser([]) empty at the start of getUser like this:
const getUser = async (username) => {
setLoading(true);
setUser([]);
const res = await axios.get(
`https://api.github.com/users/${username}?client_id=${
process.env.REACT_APP_GITHUB_CLIENT_ID}&client_secret=${
process.env.REACT_APP_GITHUB_CLIENT_SECRET}`
);
setUser(res.data);
setLoading(false);
}