React useState overwritten even with spread - reactjs

So I have a component where I have to make an API call to get some data that has IDs that I use for another async API call. My issue is I can't get the async API call to work correctly with updating the state via spread (...) so that the checks in the render can be made for displaying specific stages related to specific content.
FYI: Project is a Headless Drupal/React.
import WidgetButtonMenu from '../WidgetButtonMenu.jsx';
import { WidgetButtonType } from '../../Types/WidgetButtons.tsx';
import { getAllInitaitives, getInitiativeTaxonomyTerm } from '../../API/Initiatives.jsx';
import { useEffect } from 'react';
import { useState } from 'react';
import { stripHTML } from '../../Utilities/CommonCalls.jsx';
import '../../../CSS/Widgets/WidgetInitiativeOverview.css';
import iconAdd from '../../../Icons/Interaction/icon-add.svg';
function WidgetInitiativeOverview(props) {
const [initiatives, setInitiatives] = useState([]);
const [initiativesStages, setInitiativesStage] = useState([]);
// Get all initiatives and data
useEffect(() => {
const stages = [];
const asyncFn = async (initData) => {
await Promise.all(initData.map((initiative, index) => {
getInitiativeTaxonomyTerm(initiative.field_initiative_stage[0].target_id).then((data) => {
stages.push({
initiativeID: initiative.nid[0].value,
stageName: data.name[0].value
});
});
}));
return stages;
}
// Call data
getAllInitaitives().then((data) => {
setInitiatives(data);
asyncFn(data).then((returnStages) => {
setInitiativesStage(returnStages);
})
});
}, []);
useEffect(() => {
console.log('State of stages: ', initiativesStages);
}, [initiativesStages]);
return (
<>
<div className='widget-initiative-overview-container'>
<WidgetButtonMenu type={ WidgetButtonType.DotsMenu } />
{ initiatives.map((initiative, index) => {
return (
<div className='initiative-container' key={ index }>
<div className='top-bar'>
<div className='initiative-stage'>
{ initiativesStages.map((stage, stageIndex) => {
if (stage.initiativeID === initiative.nid[0].value) {
return stage.stageName;
}
}) }
</div>
<button className='btn-add-contributors'><img src={ iconAdd } alt='Add icon.' /></button>
</div>
<div className='initiative-title'>{ initiative.title[0].value } - NID ({ initiative.nid[0].value })</div>
<div className='initiative-description'>{ stripHTML(initiative.field_initiative_description[0].processed) }</div>
</div>
);
}) }
</div>
</>
);
}
export default WidgetInitiativeOverview;
Here's a link for video visualization: https://vimeo.com/743753924. In the video you can see that on page refresh, there is not data within the state but if I modify the code (like putting in a space) and saving it, data populates for half a second and updates correctly within the component.
I've tried using spread to make sure that the state isn't mutated but I'm still learning the ins and outs of React.
The initiatives state works fine but then again that's just 1 API call and then setting the data. The initiativeStages state can use X amount of API calls depending on the amount of initiatives are returned during the first API call.
I don't think the API calls are necessary for this question but I can give reference to them if needed. Again, I think it's just the issue with updating the state.

the function you pass to initData.map() does not return anything, so your await Promise.all() is waiting for an array of Promise.resolve(undefined) to resolve, which happens basically instantly, certainly long before your requests have finished and you had a chance to call stages.push({ ... });
That's why you setInitiativesStage([]) an empty array.
And what you do with const stages = []; and the stages.push() inside of the .then() is an antipattern, because it produces broken code like yours.
that's how I'd write that effect:
useEffect(() => {
// makes the request for a single initiative and transforms the result.
const getInitiative = initiative => getInitiativeTaxonomyTerm(
initiative.field_initiative_stage[0].target_id
).then(data => ({
initiativeID: initiative.nid[0].value,
stageName: data.name[0].value
}))
// Call data
getAllInitaitives()
.then((initiatives) => {
setInitiatives(initiatives);
Promise.all(initiatives.map(getInitiative))
.then(setInitiativesStage);
});
}, []);
this code still has a flaw (imo.) it first updates setInitiatives, then starts to make the API calls for the initiaives themselves, before also updating setInitiativesStage. So there is a (short) period of time when these two states are out of sync. You might want to delay setInitiatives(initiatives); until the other API requests have finished.
getAllInitaitives()
.then(async (initiatives) => {
const initiativesStages = await Promise.all(initiatives.map(getInitiative));
setInitiatives(initiatives);
setInitiativesStage(initiativesStages)
});

Related

Why is my component failing to run when I call it?

I am struggling to find why my component is not responding to being called by its parent. I am trying to integrate Cloud Firestore with code that previously ran using Redux. My first goal is to populate my List with data from Firestore.
Here are my (simplified) components in question:
// List.js
import React, { useEffect, useState } from "react";
import db from "../../db";
import { onSnapshot, query, collection, orderBy } from "firebase/firestore";
import TaskItem from "./TaskItem";
const List = () => {
const [taskList, setTaskList] = useState([]); // Currently assumes DB never empty, populates on initial render
const [isInitialRender, setIsInitialRender] = useState(true);
// Firestore
const ref = collection(db, "Tasks");
const q = query(ref, orderBy("listIndex"));
useEffect(() => {
// Execute only on initial render
if (isInitialRender) {
// Populate task list
onSnapshot(q, (querySnapshot) => {
setTaskList(() => querySnapshot.docs)
}, (error) => {
console.log(error)
})
};
setIsInitialRender(() => false);
}, []);
return (
<>
<h2>List</h2>
{taskList.forEach((task) => ( // console-logging `task` here will output correct data
<ul key={task.data().key}>
<TaskItem
id={task.data().key}
// docRef={taskDoc}
/>
</ul>
))
}
</>
);
};
export default List;
// TaskItem.js
import React from "react";
const TaskItem = (props) => {
console.log('This will not print')
const submitHandler = () => console.log('Submitted');
return (
<form onSubmit={submitHandler}>
<input
autoFocus
type="text"
/>
</form>
);
};
export default TaskItem;
I have tried:
Populating the state with the data from each document (rather than assigning it directly), then passing the contents as props. This led to (I believe) an infinite loop, and ideally I would like to pass the actual DocumentReference to the TaskItem anyways. So this was a bust for me.
Returning [...querySnapshot.docs], or even (prev) => prev = [...querySnapshot.docs] in the state setter. No response from TaskItem().
Decomposing the taskList state into a new dummy array, and using that array to populate the props for TaskItem.
I know that the task data is being fetched successfully because I can satisfactorily log taskList's contents from the map function in List's return statement. But it seems like TaskItem() never runs.
Does anyone see my error here?
edit: sorry I assumed you were using map. I'm not sure why your forEach isn't working but map would work, from my example
edit 2: you probably are looking to use map because you want to transform every element in the array: JavaScript: Difference between .forEach() and .map()
you forgot to return something from the map, and maybe need {} instead.
try
{taskList.forEach((task) => {
return (
<ul key={task.data().key}>
<TaskItem
id={task.data().key}
// docRef={taskDoc}
/>
</ul>
)
})

ReactJS context-api won't render after I get data

This is a next.js site, since both my Navbar component and my cart page should have access to my cart's content I created a context for them. If I try to render the page, I get:
Unhandled Runtime Error
TypeError: Cannot read properties of undefined (reading 'key')
obs: The cartContent array exists and has length 1, I can get it by delaying when the data's rendered by using setTimeout, but, can't get it to render right after it's fetched.
I need to make it render after the data from firebase is returned, but always met with the mentioned error.
This is my _app.tsx file
function MyApp({ Component, pageProps }) {
// set user for context
const userContext = startContext();
return (
<UserContext.Provider value = { userContext }>
<Navbar />
<Component {...pageProps} />
<Toaster />
</UserContext.Provider>
);
}
export default MyApp
This file has the startContext function that returns the context so it can be used.
export const startContext = () => {
const [user] = useAuthState(auth);
const [cart, setCart] = useState(null);
const [cartContent, setCartContent] = useState(null);
useEffect(() => {
if (!user) {
setCart(null);
setCartContent(null);
}
else {
getCart(user, setCart, setCartContent);
}
}, [user]);
return { user, cart, setCart, cartContent, setCartContent };
}
This file contains the getCart function.
export const getCart = async (user, setCart, setCartContent) => {
if (user) {
try {
let new_cart = await (await getDoc(doc(firestore, 'carts', user.uid))).data();
if (new_cart) {
let new_cartContent = []
await Object.keys(new_cart).map(async (key) => {
new_cartContent.push({...(await getDoc(doc(firestore, 'products-cart', key))).data(), key: key});
});
console.log(new_cartContent);
setCartContent(new_cartContent);
console.log(new_cartContent);
setCart(new_cart);
}
else {
setCart(null);
setCartContent(null);
}
} catch (err) {
console.error(err);
}
}
}
This is the cart.tsx webpage. When I load it I get the mentioned error.
export default () => {
const { user, cart, cartContent } = useContext(UserContext);
return (
<AuthCheck>
<div className="grid grid-cols-1 gap-4">
{cartContent && cartContent[0].key}
</div>
</AuthCheck>
)
}
I've tried to render the cart's content[0].key in many different ways, but couldn't do it. Always get error as if it were undefined. Doing a setTimeout hack works, but, I really wanted to solve this in a decent manner so it's at least error proof in the sense of not depending on firebase's response time/internet latency.
Edit:
Since it works with setTimeout, it feels like a race condition where if setCartContent is used, it triggers the rerender but setCartContent can't finish before stuff is rendered so it will consider the state cartContent as undefined and won't trigger again later.
Try changing
{cartContent && cartContent[0].key}
to
{cartContent?.length > 0 && cartContent[0].key}
Edit:: The actual problem is in getCart function in line
let new_cart = await (await getDoc(doc(firestore, 'carts', user.uid))).data();
This is either set to an empty array or an empty object. So try changing your if (new_cart) condition to
if (Object.keys(new_cart).length > 0) {
Now you wont get the undefined error
Since there seemed to be a race condition, I figured the setCartContent was executing before its content was fetched. So I changed in the getCart function the map loop with an async function for a for loop
await Object.keys(new_cart).map(async (key) => {
new_cartContent.push({...(await getDoc(doc(firestore, 'products-cart', key))).data(), key: key});
});
to
for (const key of Object.keys(new_cart)) {
new_cartContent.push({...(await getDoc(doc(firestore, 'products-cart', key))).data(), key: key});
}
I can't make a map function with await in it without making it asynchronous so I the for loop made it work. Hope someone finds some alternatives to solving this, I could only come up with a for loop so the code is synchronous.

Infinite Loop from Promise and useState Hook

I've managed to accidentally create an infinite loop out of a fetch promise and a useState hook in react. Can anyone point out why this is repeating? My grasp of both pieces is a little weak, and I imagine that a clear explanation with correctly functioning code would help me see how both work.
FYI - the loreReturn variable is an object with some transaction ids, and the getData function goes and grabs some text from the web using those ids.
export function TextExample(){
let testText = "no itemLore yet";
const [text, textAdd] = useState(testText);
const txs = loreReturn.data.transactions.edges;
txs.forEach ((tx) => {arweave.transactions.getData(tx.node.id, {decode: true, string: true}).then(data => {
console.log(data);
textAdd(text + data);
});
});
return (
<div>
<p>{text}</p>
<
/div>
);
};
Put your API calls inside a useEffect hook and add necessary dependencies. This will make sure you are not repeatedly running the API calls every time the component reloads
export function TextExample(){
let testText = "no itemLore yet";
const [text, textAdd] = useState(testText);
useEffect(()=>{
const txs = loreReturn.data.transactions.edges;
txs.forEach ((tx) => {
arweave.transactions.getData(tx.node.id, {decode: true, string: true})
.then(data => {
console.log(data);
textAdd(text + data);
});
});
}, [])
return (
<div>
<p>{text}</p>
</div>
);
};

map not a function using react hooks

i'm trying to populate a select bar with a name from an API call. I Have created my hook, also useEffect for its side effects, and passed the data down the return. its giving me map is not a function error. my variable is an empty array but the setter of the variable is not assigning the value to my variable. How can i clear the map not a function error ? i have attached my snippet. Thanks.
import React, { useEffect, useState } from "react";
import axios from "axios";
const Sidebar = () => {
const [ingredients, setIngredients] = useState([]);
useEffect(() => {
const fetchIngredients = async (url) => {
try {
let res = await axios.get(url);
setIngredients(res.data);
} catch (error) {
setIngredients([]);
console.log(error);
}
};
fetchIngredients(
"https://www.thecocktaildb.com/api/json/v2/1/search.php?i=vodka"
);
}, []);
const displayIngredients = ingredients.map((ingredient) => {
setIngredients(ingredient.name);
return <option key={ingredient.name}>{ingredients}</option>;
});
return (
<div className="sidebar">
<label>
By ingredient:
<select>{displayIngredients}</select>
</label>
</div>
);
};
export default Sidebar
First, here
setIngredients(res.data);
change res.data to res.ingredients (the response object doesn't have data property). Then you'll face another bug,
const displayIngredients = ingredients.map((ingredient) => {
setIngredients(ingredient.name);
//...
First, ingredient.name is undefined, and second, it probably would be a string if it existed. Just ditch the setIngredients call here.
You are declaring displayIngredients as a variable typeof array (By directly affecting the array.map() result). You need it to be a function that return an array as follow :
const displayIngredients = () => ingredients.map((ingredient) => {
// Do not erase your previous values here
setIngredients(previousState => [...previousState, ingredient.name]);
// Changed it here as well, seems more logic to me
return <option key={ingredient.name}>{ingredient.name}</option>;
});
You should also wait for the API call to end before to display your select to prevent a blank result while your data load (If there is a lot). The easiest way to do that is returning a loader while the API call is running :
if(!ingredients.length) {
return <Loader />; // Or whatever you want
}
return (
<div className="sidebar">
<label>
By ingredient:
<select>{displayIngredients}</select>
</label>
</div>
);

How to link to a show view from an index using react hooks with firestore data

I am trying to figure out how to define a link to reference that can use a firebase document id to link to a show view for that document. I can render an index. I cannot find a way to define a link to the document.
I've followed this tutorial - which is good to get the CRUD steps other than the show view. I can find other tutorials that do this with class components and the closest I've been able to find using hooks is this incomplete project repo.
I want to try and add a link in the index to show the document in a new view.
I have an index with:
const useBlogs = () => {
const [blogs, setBlogs] = useState([]); //useState() hook, sets initial state to an empty array
useEffect(() => {
const unsubscribe = Firebase
.firestore //access firestore
.collection("blog") //access "blogs" collection
.where("status", "==", true)
.orderBy("createdAt")
.get()
.then(function(querySnapshot) {
// .onSnapshot(snapshot => {
//You can "listen" to a document with the onSnapshot() method.
const listBlogs = querySnapshot.docs.map(doc => ({
//map each document into snapshot
id: doc.id, //id and data pushed into blogs array
...doc.data() //spread operator merges data to id.
}));
setBlogs(listBlogs); //blogs is equal to listBlogs
});
return
// () => unsubscribe();
}, []);
return blogs;
};
const BlogList = ({ editBlog }) => {
const listBlog = useBlogs();
return (
<div>
{listBlog.map(blog => (
<Card key={blog.id} hoverable={true} style={{marginTop: "20px", marginBottom: "20px"}}>
<Title level={4} >{blog.title} </Title>
<Tag color="geekblue" style={{ float: "right"}}>{blog.category} </Tag>
<Paragraph><Text>{blog.caption}
</Text></Paragraph>
<Link to={`/readblog/${blog.id}`}>Read</Link>
<Link to={`/blog/${blog.id}`}>Read</Link>
</Card>
))}
</div>
);
};
export default BlogList;
Then I have a route defined with:
export const BLOGINDEX = '/blog';
export const BLOGPOST = '/blog/:id';
export const NEWBLOG = '/newblog';
export const EDITBLOG = '/editblog';
export const VIEWBLOG = '/viewblog';
export const READBLOG = '/readblog/:id';
I can't find a tutorial that does this with hooks. Can anyone see how to link from an index to a document that I can show in a different page?
I did find this code sandbox. It looks like it is rendering a clean page in the updateCustomer page and using data from the index to do it - but the example is too clever for me to unpick without an explanation of what's happening (in particular, the updateCustomer file defines a setCustomer variable, by reference to useForm - but there is nothing in useForm with that definition. That variable is used in the key part of the file that tries to identify the data) - so I can't mimic the steps.
NEXT ATTEMPT
I found this blog post which suggests some changes for locating the relevant document.
I implemented these changes and while I can print the correct document.id on the read page, I cannot find a way to access the document properties (eg: blog.title).
import React, { useHook } from 'react';
import {
useParams
} from 'react-router-dom';
import Firebase from "../../../firebase";
import BlogList from './View';
function ReadBlogPost() {
let { slug } = useParams()
// ...
return (
<div>{slug}
</div>
)
};
export default ReadBlogPost;
NEXT ATTEMPT:
I tried to use the slug as the doc.id to get the post document as follows:
import React, { useHook, useEffect } from 'react';
import {
useParams
} from 'react-router-dom';
import Firebase from "../../../firebase";
import BlogList from './View';
function ReadBlogPost() {
let { slug } = useParams()
// ...
useEffect(() => {
const blog =
Firebase.firestore.collection("blog").doc(slug);
blog.get().then(function(doc) {
if (doc.exists) {
console.log("Document data:", doc.data());
doc.data();
} else {
// doc.data() will be undefined in this case
console.log("No such document!");
}
}).catch(function(error) {
console.log("Error getting document:", error);
});
});
return (
<div>{blog.title}
</div>
)
};
export default ReadBlogPost;
It returns an error saying blog is not defined. I also tried to return {doc.title} but I get the same error. I can see all the data in the console.
I really can't make sense of coding documentation - I can't figure out the starting point to decipher the instructions so most things I learn are by trial and error but I've run out of places to look for inspiration to try something new.
NEXT ATTEMPT
My next attempt is to try and follow the lead in this tutorial.
function ReadBlogPost(blog) {
let { slug } = useParams()
// ...
useEffect(() => {
const blog =
Firebase.firestore.collection("blog").doc(slug);
blog.get().then(function(doc) {
if (doc.exists) {
doc.data()
console.log("Document data:", doc.data());
} else {
// doc.data() will be undefined in this case
console.log("No such document!");
}
}).catch(function(error) {
console.log("Error getting document:", error);
});
},
[blog]
);
return (
<div><Title level={4} > {blog.title}
</Title>
<p>{console.log(blog)}</p>
</div>
)
};
export default ReadBlogPost;
When I try this, the only odd thing is that the console.log inside the useEffect method gives all the data accurately, but when I log it form inside the return method, I get a load of gibberish (shown in the picture below).
NEXT ATTEMPT
I found this tutorial, which uses realtime database instead of firestore, but I tried to copy the logic.
My read post page now has:
import React, { useHook, useEffect, useState } from 'react';
import {
useParams
} from 'react-router-dom';
import Firebase from "../../../firebase";
import BlogList from './View';
import { Card, Divider, Form, Icon, Input, Switch, Layout, Tabs, Typography, Tag, Button } from 'antd';
const { Paragraph, Text, Title } = Typography;
const ReadBlogPost = () => {
const [loading, setLoading] = useState(true);
const [currentPost, setCurrentPost] = useState();
let { slug } = useParams()
if (loading && !currentPost) {
Firebase
.firestore
.collection("blog")
.doc(slug)
.get()
.then(function(doc) {
if (doc.exists) {
setCurrentPost(...doc.data());
console.log("Document data:", doc.data());
}
}),
setLoading(false)
}
if (loading) {
return <h1>Loading...</h1>;
}
return (
<div><Title level={4} >
{currentPost.caption}
{console.log({currentPost})}
</Title>
</div>
)
};
export default ReadBlogPost;
Maybe this blog post is old, or maybe it's to do with it using .js where I have .jsx - which I think means I can't use if statements, but I can't get this to work either. The error says:
Line 21:9: Expected an assignment or function call and instead saw
an expression no-unused-expressions
It points to the line starting with Firebase.
I got rid of all the loading bits to try and make the data render. That gets rid of the above error message for now. However, I still can't return the values from currentPost.
It's really odd to me that inside the return statement, I cannot output {currentPost.title} - I get an error saying title is undefined, but when I try to output {currentPost} the error message says:
Error: Objects are not valid as a React child (found: object with keys
{caption, category, createdAt, post, status, title}). If you meant to
render a collection of children, use an array instead.
That makes no sense! I'd love to understand why I can log these values before the return statement, and inside the return statement, I can log them on the object but I cannot find how to log them as attributes.
First of all: is your useBlog() hook returning the expected data? If so, all you need to do is define your <Link/> components correctly.
<Link
// This will look like /readblog/3. Curly braces mean
// that this prop contains javascript that needs to be
// evaluated, thus allowing you to create dynamic urls.
to={`/readblog/${blog.id}`}
// Make sure to open in a new window
target="_blank"
>
Read
</Link>
Edit: If you want to pass the data to the new component you need to set up a store in order to avoid fetching the same resource twice (once when mounting the list and once when mounting the BlogPost itself)
// Define a context
const BlogListContext = React.createContext()
// In a top level component (eg. App.js) define a provider
const App = () => {
const [blogList, setBlogList] = useState([])
return (
<BlogListContext.Provider value={{blogList, setBlogList}}>
<SomeOtherComponent/>
</BlogListContext.Provider>
)
}
// In your BlogList component
const BlogList = ({ editBlog }) => {
const { setBlogList } = useContext(BlogListContext)
const listBlog = useBlogs()
// Update the blog list from the context each time the
// listBlog changes
useEffect(() => {
setBlogList(listBlog)
}, [listBlog])
return (
// your components and links here
)
}
// In your ReadBlog component
const ReadBlogComponent = ({ match }) => {
const { blogList } = useContext(BlogListContext)
// Find the blog by the id from params.
const blog = blogList.find(blog => blog.id === match.params.id) || {}
return (
// Your JSX
)
}
There are other options for passing data as well:
Through url params (not recommended).
Just pass the ID and let the component fetch its own data on mount.
I found an answer that works for each attribute other than the timestamp.
const [currentPost, setCurrentPost] = useState([]);
There is an empty array in the useState() initialised state.
In relation to the timestamps - I've been through this hell so many times with firestore timestamps - most recently here. The solution that worked in December 2019 no longer works. Back to tearing my hair out over that one...

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