I am trying to make an http request to my backend server (run on java springboot) with my React-based frontnend, which returns a string that I want to parse and assign to values. From what I have seen on the syntax pages, I want to believe that I am calling the request correctly. My error message mentions "Cannot read properties of undefined (reading 'split')", which I think means that split() is not a valid operation for js or React? Does anyone know what is the correct way to this?
import React from 'react';
import './App.css';
import Exchange from './Exchange'
import Recommendations from './Recommendations';
import axios from "axios";
function Middle(){
const response = axios.get("http://localhost:8080/run");
const data = response.data;
const dataArr = data.split(",");
return (
<div className = 'Middle'>
<h1>{data}</h1>
<Exchange name = "Coinbase" btcBuy = {dataArr[1]} btcSell = "" ethBuy = "" ethSell = ""/>
<Exchange name = "Binance" btcBuy = "" btcSell = "" ethBuy = "" ethSell = ""/>
<Recommendations/>
</div>
);
};
export default Middle;
It means that the data variable is not a string. Also you need to use useEffect if you want to fetch data.
import React, { useState, useEffect } from "react";
function Middle(){
const [data, setData] = useState([]);
useEffect(() => {
(async () => {
try {
const response = await axios.get("http://localhost:8080/run");
const data = response.data;
setData(data); // use split if you have to, I dont think you need that.
} catch(err) {
console.error(err);
}
})()
}, [])
Actually you do not read the response properly, as it is an asynchronous operation and your response is undefined at the time you make operations on it sequentially.
You have to place your code in the body of .then, like this:
let dataArr = [];
axios.get("http://localhost:8080/run")
.then(response => {
const data = response.data;
dataArr = data.split(",");
});
Related
I have a react project setup with Redux and Axios. This is a function I am using to get data from an endpoint in my Redux actions:
export const getCSEfirstStageApplicants = () => async (dispatch) => {
try {
dispatch(LOADING());
const response = await axios.get(
`${baseUrl}/Franchisee/CSEFirstStageApplication`
);
if (response.status === 200) {
const { message, data } = response?.data || {};
return { message, data };
}
} catch (error) {
const { message } = error?.response?.data || {};
return message;
} finally {
dispatch(STOP_LOADING());
}
};
My component looks something like this:
import { useState, useEffect } from "react";
import {getCSEfirstStageApplicants} from "../../../redux/user/actions";
import { useDispatch } from "react-redux";
const MyComponent = () => {
const [cseApplicants, setCseApplicants] = useState([]);
const dispatch = useDispatch();
const getFirstStage = async () => {
const response = await dispatch(getCSEfirstStageApplicants());
if (response && response.data) {
console.log(response);
setCseApplicants(response.data);
return;
}
setCseApplicants([]);
};
useEffect(() => {
getFirstStage();
}, [dispatch]);
}
Apparently, this is working fine on my localhost. But when I build the app and push it to the server, it is giving an error on Chrome and Firefox and is working on Edge (browsers I have tested), indicating that response is undefined.
Chrome shows this error:
Firefox shows this error:
At first I thought it was the way the network call was made as preflight seemed to come after the xhr request. But checking Chrome showed that wasn't the error.
Another indication was an error that showed up as asyncgenerator error. I haven't been able to find a relation with this.
add properties to the empty object
const { message, data } = response?.data || {data:[], message:''};
I am new in Nextjs, i am trying to integrate [slug.js] page, i want to know that how can we manage/get data in sidebar (similar blogs) ? in other words for blog details i used "get static path" and "props", But now i want to pass "current slug" ( to API) so i can fetch all blogs with this blog category,How can i do this ?
Client-side approach:
Since you pass the post as page-props via getStaticProps, you can either take the slug from there (if it's included in your data model), or extract the slug from the url via next's useRouter hook in case you want to do client-side fetching:
import axios from "axios"; // using axios as an example
import { useRouter } from "next/router";
const Component = () => {
const [similarPosts, setSimilarPosts] = useState([]);
const router = useRouter();
const { slug } = router.query;
const getSimilarPosts = async () => {
if (!router.isReady() || !slug) return [];
const { data } = await axios.get("/api/similar-posts-route/" + slug);
return data;
};
useEffect(() => {
if (similarPosts.length > 0) return;
(async () => {
const posts = await getSimilarPosts(); // assuming API returns an array of posts as data.
setSimilarPosts(posts);
})();
}, []);
return <div>Similar posts: {JSON.stringify(similarPosts)}</div>;
};
[...]
Server-Side approach (preferred):
I believe it would be a better approach to directly fetch similar posts inside getStaticProps to reduce API calls and for a better UX.
Inside getStaticProps you can take the slug from context.params and fetch all similar posts directly from your database/CMS, and pass them directly as props to your page component:
export async function getStaticProps({ params }) {
const { slug } = params;
// fetch similar posts directly from the database using the slug (don't call the API, it's not up yet during build phase)
const similarPosts = await executeDatabaseQueryForSimilarPosts(slug);
// [...] fetch the rest of the page props
return {
props: {
similarPosts,
// [...] return the rest of page props
},
revalidate: 60 * 30 // re-fetch the data at most every 30 minutes, so the posts stay up to date
};
}
// directly take all similar posts from props
const Component = ({similarPosts}) => {
return <div>Similar posts: {JSON.stringify(similarPosts)}</div>;
};
Here is the new script with the find function which allows me to identify a single element of the array for sure but there is still a small problem. As you can see it's my const crypto which contains the data I want to display on the front end. However when I want to call crypto at the return level the const is not recognized.
Hello again,
I updated the script now it works I can display on the front end the data I want however I have the impression that the request to the api is executed several times when I would like there to be only one request
I put below a screen of the console.log of my script.
As you can see the data requested is displayed first as undefined then it is displayed several times, then I put blocked due to the too large number of requests made in little time
Thanks for your help
How do I make my requests :
import { useState, useEffect } from "react";
function App() {
const [data, setData] = useState(null);
const [loading, setLoading] = useState(true);
const [error, setError] = useState(null)
useEffect(() => {
fetch("http://localhost:4500/coingeckotest")
.then(response => {
if (response.ok) {
return response.json()
}
throw response;
})
.then(data => {
setData(data)
})
.catch(error => {
console.error("Error fetching data: ", error)
setError(error)
})
.finally(() => {
setLoading(false)
})
}, [])
const uniswap = data&&data[0].tickers?.find(donne =>
donne.trade_url === 'https://app.uniswap.org/#/swap?
inputCurrency=0x2260fac5e5542a773aa44fbcfedf7c193bc2c599&
outputCurrency=ETH')
const uniprice = uniswap?.converted_last?.usd
const sushiswap = data&&data[1].tickers?.find(donne =>
donne.trade_url === 'https://app.sushi.com/swap?
inputCurrency=0x2260fac5e5542a773aa44fbcfedf7c193bc2c59
9&outputCurrency=ETH')
const sushiprice = sushiswap?.converted_last?.usd
const curvefinance = data&&data[2].tickers?.find(donne =>
donne.base === 'DAI')
const curveprice = curvefinance?.converted_last?.usd
const quickswap = data&&data[3].tickers?.find(donne =>
donne.trade_url === 'https://quickswap.exchange/#/swap?
inputCurrency=0x0d500b1d8e8ef31e21c99d1db9a6444d3adf127
0&outputCurrency=0xbbba073c31bf03b8acf7c28ef0738decf369
5683')
const quickprice = quickswap?.converted_last?.usd
console.log(uniprice)
console.log(sushiprice)
console.log(curveprice)
console.log(quickprice)
if (loading) return "Loading..."
if(error) return "Error !"
return (
<>
</>
)
}
export default App;
Thank you in advance for your answers
You can use the Array.find method to find out the first entry that matches a particular coin_id. The code for that would be:
const desiredCoinID = "something"; (determined by some user input)
const desiredCoinObject = data.find(coin => coin.coin_id === desiredCoinID);
const priceInUSD = desiredCoinObject?.tickers?.converted_last?.usd;
——-Updated Answer——-
Hi, this is my answer to your updated question. const crypto that you use is available only within the scope of the callback of the useEffect function, which is why you cannot see the results on your screen. There are two ways you can go about it:
First, you can declare crypto as a let outside the useEffect and then update it inside your useEffect. That way your crypto will have global scope. But there is a better way to do this, which is to use the useState hook.
You can declare a crypto, setCrypto using useState and then use the setter to update the value if crypto inside useEffect after the data fetching is over. Let me know if you need help writing code.
Probably this is a very stupid question, i'm new in Node.js and javascript, so please forgive me if the question is not properly explained or the answer is simple...
I'm trying to send 2 variables thru a url... When i send only 1 variable (artist=${term}) work all good, but I'm really stuck with about how to send 2 variables thru the url (&artist=${term1}&album=${term2})
I've work on this code so far which for 1 variable is working well... but i have no idea how to add a second or a third variable to the request:
File 1: "./services/albumInfo.js"
import { BRV_API } from '../../config';
import axios from 'axios';
import dotenv from 'dotenv';
const ALBUM_INFO = 'method=album.getinfo';
dotenv.config();
const doRequest = async (url) => {
return await axios.get(`${BRV_API}/${url}&api_key=${process.env.API_KEY}&format=json`);
};
export const infoAlbum = async (term) => {
return await doRequest(`?${ALBUM_INFO}&artist=${term}`);
};
File 2: "./repositories/albumInfo.js"
import { infoAlbum } from '../repositories/albumInfo';
import status from 'http-status';
export const albumInfo = async (req, res, next) => {
try {
const { query } = req;
const { data } = await infoAlbum(query.name);
const response = data;
res.status(status.OK).send(response);
} catch (error) {
next(error);
}
};
I know that my problem is in this part of the code (I guess)
export const infoAlbum = async (term) => {
return await doRequest(`?${ALBUM_INFO}&artist=${term1}&album=${term2}`);
};
I've been searching, and i've seen some solution, like this one, but i just don't understand those solutions or how to apply on my code (sorry for that, im a very new on this)
Any good soul who can help this newbie? (if can explain the why of the solution as well, for understand, will be amazing!!)
Thanks in advance!!
Axios provides parameters that can be added custom as the following
const your_url = process.env.URL
const infoAlbum = await axios.get(your_url,{
params: {
artist: term,
album: term2,
api_key: process.env.API_KEY,
format:'json'
}
})
console.log(infoAlbum.data.args)
note: your_url without any more parameters.
So,
I've found a solution, which is pretty ugly, but so far is working, if someone have a better option, will be amazing to know:
File 1: repositories/albumInfo.js, I've just add the console (as per #Alex028502 suggestion), to know what the code was returning:
import { BRV_API } from '../../config';
import axios from 'axios';
import dotenv from 'dotenv';
const ALBUM_INFO = 'method=album.getinfo';
dotenv.config();
const doRequest = async (url) => {
const fullurl = `${BRV_API}/?${ALBUM_INFO}${url}&api_key=${process.env.API_KEY}&format=json`;
console.log('full url is', fullurl);
return await axios.get(fullurl);
};
export const infoAlbum = async (term) => {
return await doRequest(`&${term}`);
};
File 1: services/albumInfo.js: I change the behaviour of 'infoAlbum' to make the request from his side:
import { infoAlbum } from '../repositories/albumInfo';
import status from 'http-status';
export const albumInfo = async (req, res, next) => {
try {
const { query } = req;
console.log(query);
const { data } = await infoAlbum('artist=' + query.artist + '&album=' + query.album);
const response = data;
res.status(status.OK).send(response);
} catch (error) {
next(error);
}
};
I know that probably this is not the very best way to walk away from the problem, but so far is what i have.... any other better option about how to capture the second or third parameter of the url request and then add them to the final url?
Best!
I am trying to import a csv file that is in a folder called data on the same level as this function. I've tried to incorporate the solution I found on here, but no luck and I don't know what I need to modify.
getData.jsx
import React, { useState, useEffect } from 'react';
import Papa from 'papaparse';
export default function GetData(artist) {
const data = Papa.parse(fetchCsv);
console.log(data);
return data;
}
async function fetchCsv() {
const response = await fetch('data/artist_data.csv');
const reader = response.body.getReader();
const result = await reader.read();
const decoder = new TextDecoder('utf-8');
const csv = decoder.decode(result.value);
return csv;
}
Few problems I see here.
When you do fetch('data/mycsv.csv') you are essentially making a request to http://localhost:3000/data/mycsv.csv. Check the n/w tab and you will see the response returned is your html. React first loads your root page and then checks further for routes.
Some coding errors like - you haven't called the fetchCsv fun inside GetData function. Also you need to await for fetchCsv.
Solution:
Move your data folder which has your csv file to the public folder and make corrections to your code.
import React from 'react';
import Papa from 'papaparse';
async function GetData(artist) {
const data = Papa.parse(await fetchCsv());
console.log(data);
return data;
}
async function fetchCsv() {
const response = await fetch('data/mycsv.csv');
const reader = response.body.getReader();
const result = await reader.read();
const decoder = new TextDecoder('utf-8');
const csv = await decoder.decode(result.value);
console.log('csv', csv);
return csv;
}
I have tested the above code in my local and it works fine.