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How to make a JSON response data global :)

Currently working on a stock project for my portfolio and I am using finnhub as the API.
I can log everything to my console. However I cannot render it as the "data" is not globally declared and must be inside of a certain function.
I tried rendering globally but had no luck...
So my question is how do I make 'data' global so that I can render it inside of the "StockHeader's" return ?
Heres what I have so far...
import React,{ useState, useEffect } from 'react';
const StockHeader = (data) => {
const [stocks, setStocks] = useState({});
const getStocks = () => {
//setting stocks
setStocks(stocks)
}
//calling it once
useEffect(()=> {
getStocks();
}, [])
//using finhubs ready made code from documentation
const finnhub = require('finnhub');
const api_key = finnhub.ApiClient.instance.authentications['api_key'];
api_key.apiKey = "my apikey"
const finnhubClient = new finnhub.DefaultApi()
finnhubClient.quote("AAPL", (error, data, response) => {
//I can log the data but I cant show it in my component
console.log(data.c)
});
return (
<>
{/* This says that data is not defined */}
<h1>{data.c}</h1>
</>
)
}
export default StockHeader

You just need a little bit of code reorganization so that the API request only happens once and so that you can use setStocks to store it:
const StockHeader = (data) => {
const [stocks, setStocks] = useState({});
useEffect(()=> {
//this could be separated into a `getStocks` function if you want
const finnhub = require('finnhub');
const api_key = finnhub.ApiClient.instance.authentications['api_key'];
api_key.apiKey = "my apikey"
const finnhubClient = new finnhub.DefaultApi()
finnhubClient.quote("AAPL", (error, data, response) => {
console.log(data.c);
setStocks(data.c);
});
}, []);
return (
<>
{/* You probably don't want to render `stocks` itself, but this shows you how to get access to the variable */}
<h1>{stocks}</h1>
</>
)
}

access to RESTful API in react

I have laravel in server side, that can show api with entering this url: http://localhost:8000/api/cabangs, and show this (the data as example):
[
{
"id":2,
"nm_cabang":"zxcvb",
"deskripsi":"poiuyt",
"created_at":"2020-08-08T05:25:31.000000Z",
"updated_at":"2020-08-08T05:29:23.000000Z"
},
{
"id":3,
"nm_cabang":"asdfg",
"deskripsi":"qwerty",
"created_at":"2020-08-08T05:28:26.000000Z",
"updated_at":"2020-08-08T05:28:26.000000Z"
}
]
I want to only display nm_cabang and deskripsi. if it's possible, using react hooks. thanks

You could start with something like this.
I'm assuming this is for the web so I used span and div.
const App: React.FC = () => {
const [data, setData] = React.useState();
const [isLoading, setLoading] = React.useState(true);
React.useEffect(() => {
const fetchData = async () => {
try {
const result = await fetch('http://localhost:8000/api/cabangs');
if (result.ok)
{
let json = await result.json();
setData(json);
}
} catch (e) {
//error
} finally {
setLoading(false);
}
};
fetchData();
}, []);
if (isLoading) {
return <span>Loading...</span>;
}
return (
<div>
{
data ? (
data.map((item) => {
return <span>{`${item.nm_cabang} ${item.deskripsi}`}</span>;
})
) : (
<></>
)
}
</div>
);
};

Use a library like axios or fetch, you only need to make the http request to the url and use the data you need.
https://github.com/axios/axios
https://javascript.info/fetch
I like axios

Fetch data with a custom React hook

I'm newbie in React but I'm developing an app which loads some data from the server when user open the app. App.js render this AllEvents.js component:
const AllEvents = function ({ id, go, fetchedUser }) {
const [popout, setPopout] = useState(<ScreenSpinner className="preloader" size="large" />)
const [events, setEvents] = useState([])
const [searchQuery, setSearchQuery] = useState('')
const [pageNumber, setPageNumber] = useState(1)
useEvents(setEvents, setPopout) // get events on the main page
useSearchedEvents(setEvents, setPopout, searchQuery, pageNumber)
// for ajax pagination
const handleSearch = (searchQuery) => {
setSearchQuery(searchQuery)
setPageNumber(1)
}
return(
<Panel id={id}>
<PanelHeader>Events around you</PanelHeader>
<FixedLayout vertical="top">
<Search onChange={handleSearch} />
</FixedLayout>
{popout}
{
<List id="event-list">
{
events.length > 0
?
events.map((event, i) => <EventListItem key={event.id} id={event.id} title={event.title} />)
:
<InfoMessages type="no-events" />
}
</List>
}
</Panel>
)
}
export default AllEvents
useEvents() is a custom hook in EventServerHooks.js file. EventServerHooks is designed for incapsulating different ajax requests. (Like a helper file to make AllEvents.js cleaner) Here it is:
function useEvents(setEvents, setPopout) {
useEffect(() => {
axios.get("https://server.ru/events")
.then(
(response) => {
console.log(response)
console.log(new Date())
setEvents(response.data.data)
setPopout(null)
},
(error) => {
console.log('Error while getting events: ' + error)
}
)
}, [])
return null
}
function useSearchedEvents(setEvents, setPopout, searchQuery, pageNumber) {
useEffect(() => {
setPopout(<ScreenSpinner className="preloader" size="large" />)
let cancel
axios({
method: 'GET',
url: "https://server.ru/events",
params: {q: searchQuery, page: pageNumber},
cancelToken: new axios.CancelToken(c => cancel = c)
}).then(
(response) => {
setEvents(response.data)
setPopout(null)
},
(error) => {
console.log('Error while getting events: ' + error)
}
).catch(
e => {
if (axios.isCancel(e)) return
}
)
return () => cancel()
}, [searchQuery, pageNumber])
return null
}
export { useEvents, useSearchedEvents }
And here is the small component InfoMessages from the first code listing, which display message "No results" if events array is empty:
const InfoMessages = props => {
switch (props.type) {
case 'no-events':
{console.log(new Date())}
return <Div className="no-events">No results :(</Div>
default:
return ''
}
}
export default InfoMessages
So my problem is that events periodically loads and periodically don't after app opened. As you can see in the code I put console log in useEvents() and in InfoMessages so when it's displayed it looks like this:
logs if events are displayed, and the app itself
And if it's not displayed it looks like this: logs if events are not displayed, and the app itself
I must note that data from the server is loaded perfectly in both cases, so I have totally no idea why it behaves differently with the same code. What am I missing?

Do not pass a hook to a custom hook: custom hooks are supposed to be decoupled from a specific component and possibly reused. In addition, your custom hooks return always null and that's wrong. But your code is pretty easy to fix.
In your main component you can fetch data with a custom hook and also get the loading state like this, for example:
function Events () {
const [events, loadingEvents] = useEvents([])
return loadingEvents ? <EventsSpinner /> : <div>{events.map(e => <Event key={e.id} title={e.title} />}</div>
}
In your custom hook you should return the internal state. For example:
function useEvents(initialState) {
const [events, setEvents] = useState(initialState)
const [loading, setLoading] = useState(true)
useEffect(function() {
axios.get("https://server.ru/events")
.then(
(res) => {
setEvents(res.data)
setLoading(false)
}
)
}, [])
return [events, loading]
}
In this example, the custom hook returns an array because we need two values, but you could also return an object with two key/value pairs. Or a simple variable (for example only the events array, if you didn't want the loading state), then use it like this:
const events = useEvents([])

This is another example that you can use, creating a custom hook that performs the task of fetching the information
export const useFetch = (_url) => {
const [data, setData] = useState(null);
const [loading, setLoading] = useState(true);
const [error, setError] = useState(true);
useEffect(function() {
setLoading('procesando...');
setData(null);
setError(null);
const source = axios.CancelToken.source();
setTimeout( () => {
axios.get( _url,{cancelToken: source.token})
.then(
(res) => {
setLoading(false);
console.log(res.data);
//setData(res);
res.data && setData(res.data);
// res.content && setData(res.content);
})
.catch(err =>{
setLoading(false);
setError('si un error ocurre...');
})
},1000)
return ()=>{
source.cancel();
}
}, [_url])

Fetching data from Prismic API using React Hooks

I'm trying to query data from the Prismic headless CMS API and running into problems using React Hooks. The prismic API is returning null, though I know its being passed down correctly as I can query it successfully without using react hooks.
Heres my current compontent code. Its returning "cannot read property 'api' of null". It doesn't reach the 'data' console log.
const Footer = ({ prismicCtx }) => {
const [links, setLinks] = useState([]);
useEffect(() => {
const fetchLinks = async () => {
const data = await prismicCtx.api.query([
Prismic.Predicates.at('document.tags', [`${config.source}`]),
Prismic.Predicates.at('document.type', 'footer'),
]);
console.log('data:', data);
setLinks(data.results[0].data);
};
fetchLinks();
}, []);
return (
<div>
<h1> Footer </h1>
</div>
);
};
export default Footer;

It seems to be a case where on initial render prismicCtx is null and only on the subsequent render you receive the updated value. The solution is obviously to call the effect on change of prismicCtx, but you if you just want to call the api on initial render you would need to keep track of whether you called the api earlier or not which you can achieve by using useRef and also you don't need to set the state as empty if prismicCtx doesn't exist
const Footer = ({ prismicCtx }) => {
const [links, setLinks] = useState([]);
const isFirstCall = useRef(true);
useEffect(() => {
if(prismicCtx && isFirstCall.current) {
const fetchLinks = async () => {
const data = await prismicCtx.api.query([
Prismic.Predicates.at('document.tags', [`${config.source}`]),
Prismic.Predicates.at('document.type', 'footer'),
]);
console.log('data:', data);
setLinks(data.results[0].data);
};
fetchLinks();
isFirstCall.current = false;
}
},[prismicCtx]);
return (
<div>
<h1> Footer </h1>
</div>
);
};
export default Footer;

Figured it out, I beleive. PrismicCTX was being changed up the tree so it was switching to undefinded. A simple if/else fixed it and making it so it only updated on that prop change. Still not sure if best practice though!
const Footer = ({ prismicCtx }) => {
const [links, setLinks] = useState([]);
useEffect(
() => {
const fetchLinks = async () => {
const data = await prismicCtx.api.query([
Prismic.Predicates.at('document.tags', [`${config.source}`]),
Prismic.Predicates.at('document.type', 'footer'),
]);
console.log('data:', data);
setLinks(data.results[0].data);
};
if (prismicCtx) {
fetchLinks();
} else {
setLinks([]);
}
},
[prismicCtx]
);
return (
<div>
<h1> Footer </h1>
</div>
);
};
export default Footer;

Loading effect using react hooks

I'm making an effort to implement a loading using hooks on react.
I can do it using componentDidMount, but this applications uses Hoocks.
I create the state and the changestate, but i can not set and use it on my html.
Here is my code:
First of all i made a get request whit axios and async/await
const fetchContent = async content => {
const data = []
for await (const item of content) {
const info = await axios.get(
`url/id`
)
data.push({ componentDisplay: item.title });
}
return data
}
then i call it whit usseEffect
const ContentGroups = ({ content , ads}) => {
const [contentResult, setResult] = useState([])
const [contentLoading, changeCondition] = useState(true)
const change = () => {
changeCondition(false)
}
useEffect(
() => {
fetchContent(content).then(data => setResult(data)
change()
},
[content]
)
return (
<React.Fragment>
{ contentLoading ? <Loading /> : <Conteiner> } // always show me the container, although contentLoading innitial state is true..
</div>
</React.Fragment>
)
}