I need some help with me current project making in React. I'am making a star-wars-app for my job interview and I stucked on a one problem.
Fetch efficiency.
I'am fetching this data, and then fetching some more because of the url's in the first fetched data, and everything fetches good, but first i have the 'url's' seeing in the table and then it changes into correct data.
I want to set the 'fetched' state to true when everything is rendered correctly but I don't know how to do it.
const api = `https://swapi.dev/api/people/`;
const [characters, setCharacters] = useState([]);
const [speciesOptions, setSpeciesOptions] = useState([]);
const [homeworldOptions, setHomeworldOptions] = useState([]);
const [fetched, setFetched] = useState(false);
useEffect(() => {
const fetchedTimeout = () => {
setTimeout(() => {
setFetched(true);
}, 2000);
};
const fetchArray = (array, arrName) => {
for (let elem of array) {
fetch(elem).then((response) =>
response.json().then((data) => {
array.shift();
array.push(data.name);
})
);
}
if (arrName === "species") {
if (!array.length) {
array.push("Unspecified");
}
}
};
async function fetchOtherData(characters) {
await characters.forEach((character) => {
const homeworld = character.homeworld;
const vehicles = character.vehicles;
const starships = character.starships;
const species = character.species;
fetch(homeworld).then((response) =>
response.json().then((data) =>
setCharacters((prevData) =>
prevData.map((prevCharacter) =>
prevCharacter.homeworld === homeworld
? {
...prevCharacter,
homeworld: data.name,
}
: prevCharacter
)
)
)
);
fetchArray(vehicles);
fetchArray(starships);
fetchArray(species, "species");
});
await setCharacters(characters);
await fetchedTimeout();
}
const fetchAllCharacters = (allCharacters, data) => {
if (data.next) {
fetch(data.next)
.then((response) => response.json())
.then((data) => {
allCharacters.push(...data.results);
fetchAllCharacters(allCharacters, data);
});
}
if (!data.next) {
fetchOtherData(allCharacters);
}
};
async function fetchApi() {
const allCharacters = [];
await fetch(api)
.then((response) => response.json())
.then((data) => {
allCharacters.push(...data.results);
fetchAllCharacters(allCharacters, data);
})
.catch((error) => console.log(error));
}
const setSpeciesFiltering = () => {
const speciesFiltering = [];
for (let character of characters) {
const characterSpecies = character.species.join();
const foundSpecies = speciesFiltering.indexOf(characterSpecies);
if (foundSpecies === -1) {
speciesFiltering.push(characterSpecies);
}
}
const speciesOptions = speciesFiltering.map((species) => (
<option value={species}>{species}</option>
));
setSpeciesOptions(speciesOptions);
};
const setHomeworldFiltering = () => {
const homeworldFiltering = [];
for (let character of characters) {
const characterHomeworld = character.homeworld;
const foundSpecies =
homeworldFiltering.indexOf(characterHomeworld);
if (foundSpecies === -1) {
homeworldFiltering.push(characterHomeworld);
}
}
const homeworldOptions = homeworldFiltering.map((homeworld) => (
<option value={homeworld}>{homeworld}</option>
));
setHomeworldOptions(homeworldOptions);
};
fetchApi();
setSpeciesFiltering();
setHomeworldFiltering();
}, []);
I will appreciate your response.
Okay, after all the comments (thanks for that!) i changed the code to something like this.
useEffect(() => {
const fetchOtherData = (characters) => {
const charactersWithAllData = [];
characters.forEach((character) => {
const homeworld = character.homeworld;
const species = character.species;
const vehicles = character.vehicles;
const starships = character.starships;
let urls = [homeworld, ...species, ...vehicles, ...starships];
Promise.all(
urls.map((url) => {
if (url.length) {
fetch(url)
.then((response) => response.json())
.then((data) => {
if (url.search("species") > 0) {
character.species = data.name;
}
if (url.search("planets") > 0) {
character.homeworld = data.name;
}
if (url.search("vehicles") > 0) {
character.vehicles.shift();
character.vehicles.push(data.name);
}
if (url.search("starships") > 0) {
character.starships.shift();
character.starships.push(data.name);
}
})
.catch((err) => console.error(err));
}
if (!url.length) {
if (url.search("species")) {
character.species = "Unspecified";
}
if (url.search("vehicles")) {
character.vehicles = "";
}
if (url.search("starships")) {
character.starships = "";
}
}
})
).then(charactersWithAllData.push(character));
});
return charactersWithAllData;
};
const fetchApi = () => {
const characters = [];
Promise.all(
[api].map((api) =>
fetch(api)
.then((response) => response.json())
.then((data) => characters.push(...data.results))
.then((data) => {
setCharacters(fetchOtherData(characters));
})
)
);
};
fetchApi();
}, []);
In what point do i have to set the 'characters' state ? Because in the situation above the data first shows on the screen, and then the state is set.
As other comments say, using Promise.all and refactoroing your useEffect is best solution for this.
But this might be helpful if you don't want to change a lot.
(but still consider refactor your hook)
const [loading, setLoading] = useState(0);
const isLoading = loading > 0;
// replace your fetches with below:
const myFetch = async (path) => {
try {
setLoading(loading => loading + 1);
return await fetch(path);
} finally {
setLoading(loading => loading - 1);
}
};
useEffect(() => {
// do your stuffs
}, []);
Related
I switched all my loaders from jQuery to Fetch and now none of the sliders are working but the slides themselves are showing up correctly in the DOM. I just can't seem to target them with JS.
https://www.harpercollege.edu/dev/whoward-dev-area/dev-index.php
fetch('/_resources/php/dev-home-interrupter-loader.php')
.then(function(response) {
return response.text();
})
.then(function(body) {
document.querySelector('#home-interrupter').innerHTML = body;
});
const interrupterslidesContainer = document.getElementById("interrupter-slides-container");
const interrupterslide = document.querySelector(".interrupter-slide");
const previnterrupter = document.getElementById("interrupter-slide-arrow-prev");
const nextinterrupter = document.getElementById("interrupter-slide-arrow-next");
nextinterrupter.addEventListener("click", () => {
const interrupterslideWidth = interrupterslide.clientWidth;
interrupterslidesContainer.scrollLeft += interrupterslideWidth;
});
previnterrupter.addEventListener("click", () => {
const interrupterslideWidth = interrupterslide.clientWidth;
interrupterslidesContainer.scrollLeft -= interrupterslideWidth;
});
Your code runs before the fetch even starts
fetch('/_resources/php/dev-home-interrupter-loader.php')
.then(function(response) {
return response.text();
})
.then(function(body) {
document.querySelector('#home-interrupter').innerHTML = body;
})
.then(() => {
const interrupterslidesContainer = document.getElementById("interrupter-slides-container");
const interrupterslide = document.querySelector(".interrupter-slide");
const previnterrupter = document.getElementById("interrupter-slide-arrow-prev");
const nextinterrupter = document.getElementById("interrupter-slide-arrow-next");
nextinterrupter.addEventListener("click", () => {
const interrupterslideWidth = interrupterslide.clientWidth;
interrupterslidesContainer.scrollLeft += interrupterslideWidth;
});
previnterrupter.addEventListener("click", () => {
const interrupterslideWidth = interrupterslide.clientWidth;
interrupterslidesContainer.scrollLeft -= interrupterslideWidth;
});
})
I have created a react hook to work on with multiple get request using axios
const useAxiosGetMultiple = (urls,{preventCall = false} = {}) => {
const [error, setError] = useState(false);
const [loading, setLoading] = useState(false);
const [response, setResponse] = useState(()=>{
const temp = {}
Object.keys(urls).forEach(key => temp[key] = [])
return temp
})
const [reloadToken, setReloadToken] = useState(false)
const urlObj = useRef({...urls})
const unmountedOnReload = useRef(false)
useEffect(() => {
if(preventCall === true){
return null
}
let unmounted = false;
const source = axios.CancelToken.source();
setLoading(true)
const requests = []
Object.values(urlObj.current).forEach(url => {
requests.push(
axios.get(url, {
cancelToken: source.token,
})
);
});
const result = {}
const errors = {}
console.log(requests)
Promise.allSettled(requests)
.then(resArray => {
if(!unmounted){
console.log('from promise allsettled')
console.log(resArray)
console.log(urlObj.current)
Object.keys(urlObj.current).forEach((key,i) =>{
if(resArray[i].status === 'fulfilled'){
result[key] = resArray[i].value.data.responseData
}
if(resArray[i].status === 'rejected'){
errors[key] = resArray[i].reason
result[key] = []
}
})
setError(errors)
setLoading(false)
setResponse(result)
}
})
.catch(err => {
if (!unmounted) {
setError(err);
setLoading(false);
setResponse([])
if (axios.isCancel(err)) {
console.log(`request cancelled:${err.message}`);
} else {
console.log("another error happened:" + err.message);
}
}
})
return () => {
unmounted = true;
unmountedOnReload.current = true
source.cancel("Api call cancelled on unmount");
};
}, [reloadToken,preventCall]);
const reFetchAll = () => {
setReloadToken((token) => !token);
};
const reload = (urlKey) =>{
unmountedOnReload.current = false
setLoading(true)
axios.get(urls[urlKey])
.then(res =>{
if(!unmountedOnReload.current){
setLoading(false)
setResponse({...response,[urlKey]: res.data.responseData})
}
})
.catch(err=>{
if(!unmountedOnReload.current){
setLoading(false)
setError({...error, [urlKey]: err})
setResponse({...response,[urlKey]: []})
}
})
}
return {response, loading, error, reFetchAll, reload, setLoading};
};
I call this hook as follows..
const {response,loading,setLoading,reload} = useAxiosGetMultiple({
stateCodes: StateCode.api,
countryCodes: CountryCode.api,
districts: District.api,
})
Rather than getting variable stateCodes containing state codes or countryCodes containing country codes it's returning in wrong order or returning same data in multiple variable. Every time the call happens every time it changes. I also tried axios.all method instead of Promise.all but problem remains same.
Even in chrome's network panel the response data is improper.
What's the possible cause for this error and how to fix it ?
Thanks in advance
I'm working on a project with graphs and I need to be able to cancel my requests if the user selects a different tab.
Here's my API call
export const getDifferentialData = (
sourceId: string,
sourceLine: string,
source: any
) => {
const graph1Request = getData(
sourceId,
sourceLine,
source
)
const graph2Request = getData(
sourceId,
sourceLine,
source
)
return Promise.all([graph1Request, graph2Request]).then(results => {
const [graphA, graphB] = results
return {
graphA: parsedData(graphA),
graphB: parsedData(graphB),
}
})
}
export const getData = (
sourceId: string,
sourceLine: string,
source?: any
) => {
if (sourceId && sourceLine) {
return api.get(`apiGoesHere`, { cancelToken: source.token }).then(response => {
const { data } = response
return parsedData(data)
})
} else {
return api.get(`apiGoesHere`, { cancelToken: source.token }).then(response => {
const { data } = response
return parsedData(data)
})
}
}
And the component where I'm doing the call. userDidChangeTab is called when pressing on a tab and it calls fetchGraph
const Graph: FC<Props> = () => {
const source = axios.CancelToken.source();
// we ensure that the query filters are up to date with the tab selected
const userDidChangeTab = (tabIndex: number) => {
const isDifferentialTabSelected = isDifferentialTab(tabIndex)
let newFilters = queryFilters
if (isDifferentialTabSelected) {
newFilters = {
// props go here
}
} else {
newFilters = {
// props go here
}
}
source.cancel()
fetchGraph(isDifferentialTabSelected)
setActiveTab(tabIndex)
}
// Function to fetch two differential graphs.
const fetchGraph = (isDifferential: boolean) => {
setFetching(true)
if (isDifferential) {
getDifferentialData(
sourceId,
sourceLine,
source
)
.then(({ graphA, graphB }: any) => {
setGraphData(graphA)
setMatchData(new diffMatch(graphA, graphB, 1.0))
})
.catch(reason => {
const errorMessage = errorMessageFromReason(reason)
addMessageToContainer(errorMessage, true)
})
.finally(() => {
setFetching(false)
})
} else {
getGraph(
sourceId,
sourceLine,
source
)
.then((graphData: any) => {
setGraphData(graphData)
setMatchData(null)
})
.catch(reason => {
const errorMessage = errorMessageFromReason(reason)
addMessageToContainer(errorMessage, true)
})
.finally(() => {
setFetching(false)
})
}
}
}
I try to add pagination using firebase and react redux-toolkit. I get the logic but having trouble using it with redux.
At first I wanted to set lastDoc in redux state but I got error since it is an object.
Then I changed the way and started to keep id of last document in the state. But then I can't get the firebase doc itself
const lastDocRef = firestoreDB.doc(`catalog/${publishedBooks.lastDocId}`)
is not same with
const lastDoc = snap.docs[snap.docs.length-1];
I appreciate any help how to solve this.
import { createSlice, createAsyncThunk, createEntityAdapter } from '#reduxjs/toolkit';
import firebaseService from 'app/services/firebaseService';
const firestoreDB = firebaseService.firestoreDB;
export const getPublishedBooks = createAsyncThunk('adminApp/publishedBooks/getPublishedBooks',
async (params, { dispatch, getState }) => {
const promise = firestoreDB
.collection('catalog')
.orderBy('lastPublish', 'desc')
.limit(10)
.get()
.then(snap => {
const lastDoc = snap.docs[snap.docs.length-1];
dispatch(setLastDocId(lastDoc.id));
let books = [];
snap.forEach(bookDoc => {
const id = bookDoc.id;
const data = bookDoc.data();
const lastPublish = data.lastPublish.toDate().toISOString();
books.push({ ...data, id, lastPublish });
});
return books;
})
.catch(error => {
return {}
});
const result = await promise;
return result;
}
);
export const getPublishedBooksNext = createAsyncThunk('adminApp/publishedBooks/getPublishedBooksNext',
async (params, { dispatch, getState }) => {
const { publishedBooks } = getState().adminApp;
const lastDocRef = firestoreDB.doc(`catalog/${publishedBooks.lastDocId}`)
const promise = firestoreDB
.collection('catalog')
.orderBy('lastPublish', 'desc')
.startAfter(lastDocRef)
.limit(10)
.get()
.then(snap => {
const lastDoc = snap.docs[snap.docs.length-1];
dispatch(setLastDocId(lastDoc.id));
let books = [];
snap.forEach(bookDoc => {
const id = bookDoc.id;
const data = bookDoc.data();
const lastPublish = data.lastPublish.toDate().toISOString();
books.push({ ...data, id, lastPublish });
});
return books;
})
.catch(error => {
return {}
});
const result = await promise;
return result;
}
);
const publishedBooksAdapter = createEntityAdapter({});
const initialState = publishedBooksAdapter.getInitialState({
lastDocId: null
});
export const {
selectAll: selectPublishedBooks,
selectById: selectPublishedBookById,
selectTotal: selectPublishedBooksTotal
} = publishedBooksAdapter.getSelectors(state => state.adminApp.publishedBooks);
const publishedBooksSlice = createSlice({
name: 'adminApp/publishedBooks',
initialState,
reducers: {
resetPublishedBooks: (state, action) => initialState,
setLastDocId: {
prepare: doc => {
const payload = doc
return { payload };
},
reducer: (state, action) => {
state.lastDocId = action.payload;
}
},
resetLastDocId: {
prepare: () => {
const payload = null
return { payload };
},
reducer: (state, action) => {
state.lastDocId = action.payload;
}
},
},
extraReducers: {
[getPublishedBooks.fulfilled]: publishedBooksAdapter.setAll,
[getPublishedBooksNext.fulfilled]: publishedBooksAdapter.upsertMany
}
});
export const { resetPublishedBooks, setLastDocId, resetLastDocId } = publishedBooksSlice.actions;
export default publishedBooksSlice.reducer;
lastDocRef only returns the doc reference. You need to get the actual doc itself.
const lastDocRef = await firestoreDB.doc(`catalog/${publishedBooks.lastDocId}`).get();
And you should use await instead of then-catch for more readble code.
export const getPublishedBooksNext = createAsyncThunk('adminApp/publishedBooks/getPublishedBooksNext',
async (params, { dispatch, getState }) => {
const { publishedBooks } = getState().adminApp;
try {
const lastDocRef = await firestoreDB.doc(`catalog/${publishedBooks.lastDocId}`).get();
const snap = await firestoreDB
.collection('catalog')
.orderBy('lastPublish', 'desc')
.startAfter(lastDocRef)
.limit(10)
.get()
const lastDoc = snap.docs[snap.docs.length-1];
let books = [];
dispatch(setLastDocId(lastDoc.id));
snap.forEach(bookDoc => {
const id = bookDoc.id;
const data = bookDoc.data();
const lastPublish = data.lastPublish.toDate().toISOString();
books.push({ ...data, id, lastPublish });
});
return books;
} catch (error) {
return {}
}
}
);
Edit: You can also save the lastDoc to redux then reference it later to avoid additional workload fetching for the lastDocRef.
export const getPublishedBooksNext = createAsyncThunk('adminApp/publishedBooks/getPublishedBooksNext',
async (params, { dispatch, getState }) => {
const { lastDocRef } = getState().adminApp; // get saved lastDoc
try {
const snap = await firestoreDB
.collection('catalog')
.orderBy('lastPublish', 'desc')
.startAfter(lastDocRef) // use it here.
.limit(10)
.get()
const lastDoc = snap.docs[snap.docs.length-1];
let books = [];
// dispatch(setLastDocId(lastDoc.id)); // instead of saving the doc id
dispatch(setLastDoc(lastDoc)); // save the last document instead
snap.forEach(bookDoc => {
const id = bookDoc.id;
const data = bookDoc.data();
const lastPublish = data.lastPublish.toDate().toISOString();
books.push({ ...data, id, lastPublish });
});
return books;
} catch (error) {
return {}
}
}
);
I tried to download the image which is in firebase storage which link is store in database. When I tried to download the image, it takes more time to execute while for loop is completed.
Is there any process that somehow I download in time which doesn't make the function really slow? I already solve this issue using setTimeout but I hope there may be a better solution than mine. Help me! thank you!
export const shampooHandler = () => {
return (dispatch) => {
dispatch(shampooStart());
const data = [];
const imgList = [];
fire
.database()
.ref()
.child("Shampoo")
.once("value")
.then((response) => {
for (let i = 0; i < response.val().length; i++) {
fire.storage().refFromURL(response.val()[i].img).getDownloadURL().then((image) => {
imgList.push(image);
})
.catch((error) => {
dispatch(shampooError(error));
});
setTimeout(() => {
name = response.val()[i].name;
description = response.val()[i].description;
value = response.val()[i].value;
img = imgList[i];
data.push({ name, description, value, img });
if (i === (response.val().length - 1)) {
dispatch(shampooSuccess(data));
}
}, 3000);
}
})
.catch((error) => {
dispatch(shampooError(error));
});
};
};
I spend a day finding a right solution for it. It may help someone to find solution in future. Thanks guys for giving a thought and specially DougStevensen to tiggering me an idea
export const shampooHandler = () => {
return (dispatch) => {
dispatch(shampooStart());
const data = [];
const imglist = [];
fire.database().ref().child("Shampoo").once("value").then((response) => {
response.val().forEach(element => {
const promise = imageUrlHandler(element.img).then(url => {
return url;
}).catch(error =>{
dispatch(shampooError(error));
})
imglist.push(promise);
//all the promise call to download the images
Promise.all(imglist).then(items =>{
const dataCollection = {
name: element.name,
description: element.description,
value: element.value,
img: items[items.length - 1]
}
data.push(dataCollection);
if(data.length === response.val().length){
dispatch(shampooSuccess(data));
}
}).catch(err =>dispatch(shampooError(err)));
})
}).catch(error => {
dispatch(shampooError(error));
})
}
}
export const imageUrlHandler = (databaseUrl) => {
return new Promise((resolve,reject)=> {
fire.storage().refFromURL(databaseUrl).getDownloadURL().then((url) => {
resolve(url);
})
.catch((error) => {
reject(error)
});
})
}