Stop invoking custom hook on first render - reactjs

I started having fun with custom hooks recently. I am mostly using them to fetch from api. The thing is that since I cannot really put useFetchLink inside of functions or useEffect i dont know how to prevent it from fetching after website first render. I could put some ifs in the hook but isn't there any other way?
***component***
export default function LinkShortener({ setLinkArr }) {
const [nextLink, setNextLink] = useState();
const inputRef = useRef(null);
const handleClick = () => {
setNextLink(inputRef.current.value);
};
const { shortLink, loading, error } = useFetchLink(nextLink);
useEffect(() => {
setLinkArr((prev) => [
...prev,
{
id: prev.length === 0 ? 1 : prev[prev.length - 1].id + 1,
long: nextLink,
short: shortLink,
},
]);
inputRef.current.value = "";
}, [shortLink, error]);
return (
<LinkShortenerContainer>
<InputContainer>
<LinkInput ref={inputRef} type="text" />
</InputContainer>
<Button
size={buttonSize.medium}
text={
loading ? (
<Loader />
) : (
<FormattedMessage
id="linkShortener.shortenItBtn"
defaultMessage="Shorten It !"
/>
)
}
onClick={handleClick}
></Button>
</LinkShortenerContainer>
);
}
***hook***
const useFetchLink = (linkToShorten) => {
const [shortLink, setShortLink] = useState("");
const [loading, setLoading] = useState(false);
const [error, setError] = useState("");
const fetchLink = async () => {
setLoading(true);
try {
const response = await fetch(
`https://api.shrtco.de/v2/shorten?url=${linkToShorten}`
);
if (response.ok) {
const data = await response.json();
setShortLink(data.result.short_link);
} else {
throw response.status;
}
} catch (err) {
setError(err);
} finally {
setLoading(false);
}
};
useEffect(() => {
fetchLink(linkToShorten);
}, [linkToShorten]);
const value = { shortLink, loading, error };
return value;
};```

Why not using directly fetchLink function and calling it whenever you need inside the component? I would change the hook in this way without useEffect inside
const useFetchLink = (linkToShorten) => {
const [shortLink, setShortLink] = useState("");
const [loading, setLoading] = useState(false);
const [error, setError] = useState("");
const fetchLink = async () => {
setLoading(true);
try {
const response = await fetch(
`https://api.shrtco.de/v2/shorten?url=${linkToShorten}`
);
if (response.ok) {
const data = await response.json();
setShortLink(data.result.short_link);
} else {
throw response.status;
}
} catch (err) {
setError(err);
} finally {
setLoading(false);
}
};
const value = { shortLink, loading, error, fetchLink };
return value;
};

Generally speaking - the standard way to avoid useEffect from running of 1st render is to use a boolean ref initialized with false, and toggled to true after first render - see this answer.
However, in your case, you don't want to call the function if linkToShorten is empty, even if it's not the 1st render, so use an if inside useEffect.
const useFetchLink = (linkToShorten) => {
const [shortLink, setShortLink] = useState("");
const [loading, setLoading] = useState(false);
const [error, setError] = useState("");
const fetchLink = useCallback(async (linkToShorten) => {
setLoading(true);
try {
const response = await fetch(
`https://api.shrtco.de/v2/shorten?url=${linkToShorten}`
);
if (response.ok) {
const data = await response.json();
setShortLink(data.result.short_link);
} else {
throw response.status;
}
} catch (err) {
setError(err);
} finally {
setLoading(false);
}
}, []);
useEffect(() => {
if(linkToShorten) fetchLink(linkToShorten);
}, [fetchLink, linkToShorten]);
const value = { shortLink, loading, error };
return value;
};

Related

How to effectively refresh the data in a custom hook using react-infinite-scroll-component when an item is deleted?

I am using a custom hook useInfiniteFetchSearch to fetch and search data for a infinite scroll component built using react-infinite-scroll-component.
The hook makes an API call and sets the data in the state using setData. Currently, I am using refreshData() method to refresh the data again when an item is deleted from the list.
However, I am not satisfied with this solution as it calls the API again even though I already have the data. Is there a more efficient way to refresh the data and update the infinite scroll component without making another API call?
Here is my custom hook implementation:
import { useState, useEffect, useRef } from "react";
import axios from "axios";
const useInfiniteFetchSearch = (api, resultsPerPage, sort = null) => {
const [data, setData] = useState([]);
const [hasMore, setHasMore] = useState(true);
const [page, setPage] = useState(2);
const [loading, setLoading] = useState(false);
const [searchTerm, setSearchTerm] = useState("");
const searchTermRef = useRef(null);
useEffect(() => {
const searchData = async () => {
try {
setLoading(true);
let query = `${api}${
searchTerm === "" ? `?` : `?search=${searchTerm}&`
}page=1`;
query = sort ? `${query}&sort=${sort}` : query;
const result = await axios.post(query);
const fetchedData = result.data;
setData(fetchedData);
setPage(2);
setHasMore(fetchedData.length === resultsPerPage);
} catch (error) {
console.error(error);
} finally {
setLoading(false);
}
};
searchData();
}, [searchTerm, api, resultsPerPage, sort]);
const refreshData = async () => {
try {
setLoading(true);
let query = `${api}${
searchTerm === "" ? `?` : `?search=${searchTerm}&`
}page=1`;
query = sort ? `${query}&sort=${sort}` : query;
const result = await axios.post(query);
const fetchedData = result.data;
setData(fetchedData);
setPage(2);
setHasMore(fetchedData.length === resultsPerPage);
} catch (error) {
console.error(error);
} finally {
setLoading(false);
}
};
const fetchMore = async () => {
try {
setLoading(true);
let query = `${api}?search=${searchTerm}&page=${page}`;
query = sort ? `${query}&sort=${sort}` : query;
const result = await axios.post(query);
const newData = result.data;
setData((prev) => [...prev, ...newData]);
setPage(page + 1);
setHasMore(newData.length === resultsPerPage);
} catch (error) {
console.error(error);
} finally {
setLoading(false);
}
};
const handleSearch = async (e) => {
e.preventDefault();
setSearchTerm(searchTermRef.current.value);
};
const handleDelete = async (e, itemId) => {
try {
await axios.delete(`${api}${itemId}`);
setData((prevData) => prevData.filter((item) => item.id !== itemId));
refreshData();
} catch (error) {
console.log(error);
} finally {
}
};
return {
state: { data, hasMore, loading, searchTermRef, searchTerm },
handlers: {
fetchMore,
setSearchTerm,
handleSearch,
handleDelete,
},
};
};
export default useInfiniteFetchSearch;
I am using this hook in my component:
const { state, handlers } = useInfiniteFetchSearch("/api/guides/search", 5);
const { data, hasMore, loading, searchTermRef, searchTerm } = state;
const { fetchMore, handleSearch, setSearchTerm, handleDelete } = handlers;
....
<InfiniteScroll
dataLength={data.length}
next={fetchMore}
hasMore={hasMore}
scrollableTarget="scrollableDiv"
loader={
<div className="flex justify-center items-center mx-auto">
<Loader />
</div>
}
>
<div className="space-y-1">
{data &&
data.map((item, index) => (
<GuidesItem
key={index}
guide={item}
handleDelete={handleDelete}
/>
))}
</div>
</InfiniteScroll>
I would appreciate any suggestions or solutions to this problem, thank you!

How to display ActivityIndicator untill all elements are mapped

I have this screen in which I want to see ActivityIndicator untill all devices are mapped (not fetched):
const MyScreen = () => {
const [devices, setDevices] = useState();
const [isLoading, setIsLoading] = useState(true);
useEffect(() => {
getDevices();
}, []);
const getDevices = async () => {
const pulledDevices = await fetchDevices();
setDevices(pulledDevices)
setIsLoading(false)
};
if (isLoading)
return (
<ActivityIndicator />
);
return (
<View >
{devices?.map((device) => {
return (
<View>
<Text>{device.name}</Text>
</View>
);
})}
</View>
);
};
Mapping these devices takes some time.
How could I implement here ActivityIndicator untill all devices are mapped.
I suggest you to use a bit more sophisticated async await hook to handle this.
useAsyncHook.js
const useAsync = asyncFunction => {
const [loading, setLoading] = useState(false);
const [result, setResult] = useState(null);
const [error, setError] = useState(null);
const execute = useCallback(async () => {
setLoading(true);
setResult(null);
setError(null);
try {
const response = await asyncFunction();
setResult(response);
setLoading(false);
} catch (error) {
setError(error);
setLoading(false);
}
}, [asyncFunction]);
useEffect(() => {
execute();
}, [execute]);
return { loading, result, error };
};
This is a raw use async hook that can be enhanced many way but it handles the loading state correctly in this state.
Usage:
const { loading, result, error } = useAsync(yourFunction);
if (loading) return null;
return <Component />;

React. How to make function with state?

I'm learning React Native and can't understand how to make function or component instead of repeated part of my code:
export const PostScreen = () => {
const postId = 1
/* THIS PART IS REPEATED IN MANY FILES */
const [data, setData] = useState([]);
const [loader, setLoader] = useState(false);
const [error, setError] = useState(null);
const fetchData = async () => {
setError(null)
setLoader(true)
try {
const data = await Api.get(`http://localhost/api/posts/${postId}`)
if (data.success == 1) {
setData(data.data)
}
else {
setError(data.error)
}
}
catch(e) {
console.log(e)
setError('Some problems')
}
finally {
setLoader(false)
}
}
useEffect(() => {
fetchData()
}, [])
if (loader) {
return <Loader />
}
if (error) {
return <View><Text>{error}</Text></View>
}
/*END>>> THIS PART IS REPEATED IN MANY FILES */
return (
<View><Text>{data.title}</Text></View>
)
}
The problem is that fetchData is working with state. I found, how to do it with Context, but I don't wont to use it. Is there any way to do clear code without Context?
So, why not make your own hook, then?
Write the hook in a dedicated module:
function useMyOwnHook(props) {
const {
postId,
} = props;
const [data, setData] = useState([]);
const [loader, setLoader] = useState(false);
const [error, setError] = useState(null);
const fetchData = async () => {
setError(null)
setLoader(true)
try {
const data = await Api.get(`http://localhost/api/posts/${postId}`)
if (data.success == 1) {
setData(data.data)
}
else {
setError(data.error)
}
}
catch(e) {
console.log(e)
setError('Some problems')
}
finally {
setLoader(false)
}
}
useEffect(() => {
fetchData()
}, [])
const render = loader
? <Loader />
: error
? <View><Text>{error}</Text></View>
: null;
return {
data,
render,
}
}
At that point, the component will be written as follows:
export const PostScreen = () => {
const postId = 1
const {
render,
data,
} = useMyOwnHook({ postId });
return render ?? (
<View><Text>{data.title}</Text></View>
)
}

React hooks - fetching data from api and passing to a component

So basically, I'm trying to fetch data from api and pass it to Component.
I create usePosition hook to get my positon from browser, and then get response from api. I really don't know how to wait with useEffect for my position, when i'm executing this code now I'm getting always log 'no position'.
const usePosition = () => {
const [error, setError] = useState(null);
const [position, setPosition] = useState();
useEffect(() => {
const geo = navigator.geolocation;
if(!geo) {
setError('Geolocation is not supported.');
return;
}
const handleSuccess = position => {
const { latitude, longitude } = position.coords;
setPosition({
latitude,
longitude
});
};
const handleError = error => {
setError(error.message);
};
geo.getCurrentPosition(handleSuccess, handleError);
}, []);
return { position, error };
}
function App() {
const {position, error} = usePositon();
const [weather, setWeather] = useState([]);
useEffect(() => {
if(position) {
const URL = `https://api.openweathermap.org/data/2.5/onecall?lat=${position.latitude}&lon=${position.longitude}&exclude=current,minutely,daily&units=metric&lang=pl&appid=${API_KEY}`;
const fetchData = async () => {
const result = await fetch(URL)
.then(res => res.json())
.then(data => data);
setWeather(result.hourly);
}
fetchData();
} else {
console.log('no position');
}
}, []);
return (
<div className="App">
<div>
<Swiper weather={weather}/>
</div>
</div>
)
}
It's all because of [] empty dependencies list down in App's useEffect. It runs exactly once on mount, when usePosition has not requested anything yet. And once it successes later and returns different { error, position } App does not react.
How to solve? Provide things as dependencies:
useEffect(() => {
if(position) {
const URL = `https://api.openweathermap.org/data/2.5/onecall?lat=${position.latitude}&lon=${position.longitude}&exclude=current,minutely,daily&units=metric&lang=pl&appid=${API_KEY}`;
const fetchData = async () => {
const result = await fetch(URL)
.then(res => res.json())
.then(data => data);
setWeather(result.hourly);
}
fetchData();
} else {
console.log('no position');
}
}, [position, error]);

Refactor a functional component with React hooks

I have several functional components which share the same logic. So I would like to refactor them using React hooks. All of them make some calls to the server on mount to check if the order has been paid. If yes, paid state is set to true , and a file is being downloaded. On submit I check if paid state is set to true, if yes, the same file is being downloaded, if not, a new order is created and a user is being redirected to a page with a payment form.
I have already extracted all functions (getOrder(), getPaymentState(), createOrder(), initPayment() and downloadFile()) which make API calls to the server. How can I further optimize this code, so that I could move checkOrder(), checkPayment(), downloadPDF() and newOrder() outside the component to use the same logic with other components as well?
Here is my component:
const Form = () => {
const [paid, setPaid] = useState(false);
const [submitting, setSubmitting] = useState(false);
const [loading, setLoading] = useState(false);
const [data, setData] = useState({});
const checkOrder = async () => {
let search = new URLSearchParams(window.location.search);
let success = search.get("Success");
if (success) {
try {
const data = await getOrder();
setData(data);
checkPayment(data);
} catch (err) {
alert(err.message)
}
}
};
const checkPayment = async values => {
try {
const paid = await getPaymentState();
setPaid(paid);
downloadPDF(values);
} catch (err) {
alert(err.message)
}
};
const downloadPDF = async values => {
setLoading(true);
let downloadData = {
email: values.email,
phone: values.phone
}
const response = await downloadFile(downloadData, sendURL);
setLoading(false);
window.location.assign(response.pdf);
}
const newOrder = async values => {
setSubmitting(true);
const order = await createOrder(values, description, sum);
const paymentUrl = await initPayment(order, description, sum, returnURL);
setSubmitting(false);
window.location.assign(paymentUrl);
}
const onSubmit = async values => {
if (paid) {
try {
downloadPDF(data);
} catch (err) {
console.log(err);
}
} else {
try {
newOrder(values)
} catch (err) {
alert(err.message)
}
}
};
useEffect(() => {
checkOrder();
}, []);
return (
)
}
EDIT 1: I also need to be able to pass some data to this hook: downloadData, sendURL, description, sum and returnURL, which will be different in each case. downloadData then needs to be populated with some data from the values.
I would appreciate if you could point me at the right direction. I'm just learning React and I would really like to find the correct way to do this.
EDIT 2: I've posted my own answer with the working code based on the previous answers. It's not final, because I still need to move downloadPDF() outside the component and pass downloadData to it, but when I do so, I get an error, that values are undefined. If anybody can help me with that, I will accept it as an answer.
I made a quick refactor of the code and put it in a custom hook, it looks like search param is the key for when the effect needs to run.
const useCheckPayment = (search) => {
const [paid, setPaid] = useState(false);
const [submitting, setSubmitting] = useState(false);
const [loading, setLoading] = useState(false);
const [data, setData] = useState({});
const checkOrder = useCallback(async () => {
let paramSearch = new URLSearchParams(search);
let success = paramSearch.get('Success');
if (success) {
try {
//why not just pass it, makes getOrder a little less impure
const data = await getOrder(paramSearch);
setData(data);
checkPayment(data);
} catch (err) {
alert(err.message);
}
}
}, [checkPayment, search]);
const checkPayment = useCallback(async (values) => {
try {
const paid = await getPaymentState();
setPaid(paid);
downloadPDF(values);
} catch (err) {
alert(err.message);
}
}, []);
const downloadPDF = async (values) => {
setLoading(true);
const response = await downloadFile();
setLoading(false);
window.location.assign(response.pdf);
};
const newOrder = async (values) => {
setSubmitting(true);
const order = await createOrder();
const paymentUrl = await initPayment(order);
setSubmitting(false);
window.location.assign(paymentUrl);
};
const onSubmit = useCallback(
async (values) => {
if (paid) {
try {
downloadPDF(data);
} catch (err) {
console.log(err);
}
} else {
try {
newOrder(values);
} catch (err) {
alert(err.message);
}
}
},
[data, paid]
);
useEffect(() => {
checkOrder();
}, [checkOrder]); //checkOrder will change when search changes and effect is called again
return { onSubmit, submitting, loading };
};
const Form = () => {
const { onSubmit, submitting, loading } = useCheckPayment(
window.location.search
);
return '';
};
You can extract out all the generic things from within the Form component into a custom Hook and return the required values from this hook
The values which are dependencies and will vary according to the component this is being called from can be passed as arguments to the hook. Also the hook can return a onSubmit function to which you can pass on the downloadData
const useOrderHook = ({returnURL, sendURL, }) => {
const [paid, setPaid] = useState(false);
const [submitting, setSubmitting] = useState(false);
const [loading, setLoading] = useState(false);
const [data, setData] = useState({});
const checkOrder = async () => {
let search = new URLSearchParams(window.location.search);
let success = search.get("Success");
if (success) {
try {
const data = await getOrder();
setData(data);
checkPayment(data);
} catch (err) {
alert(err.message)
}
}
};
const checkPayment = async values => {
try {
const paid = await getPaymentState();
setPaid(paid);
downloadPDF(values);
} catch (err) {
alert(err.message)
}
};
const downloadPDF = async values => {
setLoading(true);
let downloadData = {
email: values.email,
phone: values.phone
}
const response = await downloadFile(downloadData, sendURL);
setLoading(false);
window.location.assign(response.pdf);
}
const newOrder = async (values, description, sum) => {
setSubmitting(true);
const order = await createOrder(values, description, sum);
const paymentUrl = await initPayment(order, description, sum, returnURL);
setSubmitting(false);
window.location.assign(paymentUrl);
}
const onSubmit = async ({values, downloadData: data, description, sum}) => {
if (paid) {
try {
downloadPDF(data);
} catch (err) {
console.log(err);
}
} else {
try {
newOrder(values, description, sum)
} catch (err) {
alert(err.message)
}
}
};
useEffect(() => {
checkOrder();
}, []);
return {onSubmit, loading, submitting, paid, data };
}
Now you can use this hook in component like Form as follows
const Form = () => {
const {onSubmit, newOrder, loading, submitting, paid, data } = useOrderHook({returnUrl: 'someUrl', sendURL: 'Some send URL'})
const handleSubmit = (values) => {
// since this function is called, you can get the values from its closure.
const data = {email: values.email, phone: values.phone}
onSubmit({ data, values, description, sum})// pass in the required values for onSubmit here. you can do the same when you actually call newOrder from somewhere
}
// this is how you pass on handleSubmit to React-final-form
return <Form
onSubmit={handleSubmit }
render={({ handleSubmit }) => {
return <form onSubmit={handleSubmit}>...fields go here...</form>
}}
/>
}
Based on the answers above I came up with the following code.
The hook:
const useCheckPayment = ({initialValues, sendUrl, successUrl, description, sum, downloadPDF}) => {
const [paid, setPaid] = useState(false);
const [loading, setLoading] = useState(false);
const [submitting, setSubmitting] = useState(false);
const [data, setData] = useState(initialValues);
const checkOrder = useCallback(
async () => {
let search = new URLSearchParams(window.location.search);
let success = search.get('Success');
if (success) {
try {
const data = await getOrder(search);
setData(data);
checkPayment(search);
} catch (err) {
alert(err.message);
}
}
}, [checkPayment]
);
const checkPayment = useCallback(
async (search) => {
try {
const paid = await getPaymentState(search);
setPaid(paid);
document.getElementById('myForm').dispatchEvent(new Event('submit', { cancelable: true }))
} catch (err) {
alert(err.message);
}
}, []
);
const newOrder = useCallback(
async (values) => {
setSubmitting(true);
const order = await createOrder(values, description, sum);
const paymentUrl = await initPayment(order, description, sum, successUrl);
setSubmitting(false);
window.location.assign(paymentUrl);
}, [description, sum, successUrl]
);
const downloadPDF = async (values, downloadData) => {
setLoading(true);
const response = await downloadFile(downloadData, sendUrl);
setLoading(false);
window.location.assign(response.pdf);
};
const onSubmit = useCallback(
async ({ values, downloadData }) => {
if (paid) {
try {
downloadPDF(values, downloadData);
} catch (err) {
console.log(err);
}
} else {
try {
newOrder(values);
} catch (err) {
alert(err.message);
}
}
},
[paid, downloadPDF, newOrder]
);
useEffect(() => {
checkOrder();
}, [checkOrder]);
return { onSubmit, submitting };
};
The component:
const sendUrl = 'https://app.example.com/send'
const successUrl = 'https://example.com/success'
const description = 'Download PDF file'
const sum = '100'
const Form = () => {
const handleSubmit = (values) => {
const downloadData = {
email: values.email,
phone: values.phone
}
onSubmit({ downloadData, values })
}
const { onSubmit, submitting } = useCheckPayment(
{sendUrl, successUrl, description, sum}
);
return (
<Form
onSubmit={handleSubmit}
render={({ handleSubmit }) => (
<form onSubmit={handleSubmit}></form>
)}
/>
)
}

Resources