Passing fetched data to context-Provider in react - reactjs

I am fetching data from a English language dictionary API and creating a front end in react JS. The code works if I render out all components in the Form.js but I am trying to pass returned data to the wordDataContext to create components separately.
import React, {useEffect, useState , useContext } from 'react';
import {UserContext} from '../context/UserContext';
import {WordContext,WordProvider} from '../context/WordContext';
const getWord = async() => {
if (word !== '') {
setWord(word)
try {
const response = await fetch(`https://mydictionaryapi.appspot.com/?define=${word}`)
const data = await response.json()
iterateObject(data)
setWordData(data) // pass to context
console.log('word data', wordData)
} catch(error) {
let message = "Word NOT Found - Check spellings or connection"
setMeaning(message)
console.log(error)
}
}
}
I am then iterating over the returned dictionary object to extract definitions(meanings), synonyms and example sentence etc.
function iterateObject(data) {
for (var item in data) {
if (typeof(data[item]) == "object"){
if (item === "synonyms"){
var synonyms = data[item]
setSynonyms(synonyms)
}
iterateObject(data[item])
}
else
{
if (item === "definition") {
var meaning = data[item]
setMeaning(meaning)
}
if (item === "example"){
var example = data[item]
setExample(example)
}
}
}
}
I can render out components from iteration but I want to pass the dictionary object ( or iterated items ) to a global wordDataContext to make separate components. Here is the code for my wordDataContext and Provider,
import React, {useState, createContext } from 'react';
export const WordContext = createContext([ [{}], () => {}])
export const WordProvider= (props) => {
const [wordData , setWordData] = useState({ word:'' , meaning:'', synonyms:{} , example:'' })
return(
<WordContext.Provider value={[wordData, setWordData]}>
{props.children}
</WordContext.Provider>
)
}
Unfortunately, the returned object is not getting passed to the WordDataContext I have tried doing so after fetching the data in API call function and also when iterating but only get an empty array

Related

How to fix invalid hook call error in my airtable extension?

I'm getting this error in my Airtable blocks extension:
Error: Invalid hook call. Hooks can only be called inside of the body of a function component.
I'm unsure as to why. My program uses airtable blocks api to create a dropdown that sets a useState value, before useEffect updates a database live. Both hooks are being used inside the function body, and the function should be a react component, so I don't understand where the error lies. I've seen it can be due to react version conflicts and such as well, but I'm not sure how to confirm whether or not that is the underlying issue.
import React, { useEffect, useState } from 'react';
import ReactDOM from 'react-dom';
import {
Select,
initializeBlock,
SelectSynced,
useBase,
useRecords,
BaseProvider,
useGlobalConfig,
expandRecord,
TablePickerSynced,
ViewPickerSynced,
FieldPickerSynced,
FormField,
Input,
Button,
Box,
Icon,
} from '#airtable/blocks/ui';
import { FieldType } from '#airtable/blocks/models';
const base = useBase();
const table = base.getTable("National Works In Progress");
export default function FilterApp() {
// YOUR CODE GOES HERE
let records = useRecords(table);
var aunumbers_array = [];
const [value, setValue] = useState("");
const queryResult = table.selectRecords({ fields: ["AU Number"] });
records.forEach(function (x) {
if (aunumbers_array.indexOf(x.getCellValueAsString("AU Number"), -1)) {
aunumbers_array.push({ value: x.getCellValueAsString("AU Number"), label: x.getCellValueAsString("AU Number") })
}
});
queryResult.unloadData();
let updates = [];
useEffect(() => {
const fetchData = async () => {
records.forEach(function (x) {
if (x.getCellValueAsString('AU Number') == value) {
updates.push({ id: x.id, fields: { 'Matches Filter': true } });
console.log(value);
}
else if (x.getCellValueAsString('AU Number') !== value && x.getCellValueAsString('Matches Filter') == 'checked') {
updates.push({ id: x.id, fields: { 'Matches Filter': false } });
}
});
while (updates.length) {
await table.updateRecordsAsync(updates.splice(0, 50));
}
}
// call the function
fetchData()
// make sure to catch any error
.catch(console.error);
}, [value])
return (
<div>
<FormField label="Text field">
<Select
options={aunumbers_array}
value={value}
onChange={newValue => setValue(newValue.toString())}
width="320px"
/>
</FormField>
</div>
);
}
The error is because you are calling useBase, a custom hook in an invalid way.
const base = useBase();
This is wrong way of calling a hook as hooks can only be called inside of the body of a function component.
Move the hook call inside FilterApp() functional component.

How to loop through array after data fetching is completed?

I am a little new to react, and I am trying to loop through a list of menu items after it has been loaded. I set the sate to empty and put a condition to only start to use the .map() when the state is not empty. But i keep getting TypeError: menu_items.map is not a function.
I know that it gets loaded because when i do a console.log(menu_items) it shows the menu item.
I am little but confused on this one. Any help would be really appreciated.
import {useEffect} from 'react';
import {connect} from 'react-redux'
import {getMenu} from '../service/thunks'
const StoreMenu = ({loadMenu,match,menu_items}) => {
useEffect(()=> loadMenu(match.params.id),[]);
if(menu_items !== "") {
{
menu_items.map(menu_item => console.log(menu_item.item_name))
}
}
return (<div> tesr</div>);
}
const mapStateToProps = state => (
{
menu_items : state.menuItems
}
)
const mapDispatchToProps = dispatch => (
{
loadMenu: (store_id) => dispatch(getMenu(store_id))
}
)
export default connect(mapStateToProps,mapDispatchToProps)(StoreMenu);
Fix the code to:
if (menu_items && menu_items.length > 0) {
menu_items.map(menu_item => console.log(menu_item.item_name))
}
return (
// Create JSX here.
);

React Hooks, copied data keeps changing original source data

I'm creating a filtering page. I make a call to the api and then I copy the data so that with each filter requests i'm filtering from the original source. But for some reason when i'm filtering it's modifying my source. So when i filter twice its giving me wrong data. I put flags to make sure my reducer isnt' being called again.
import React, {
useEffect,
useState
} from 'react';
import {
useDispatch,
useSelector
} from "react-redux";
import {
useParams
} from "#reach/router"
import {
fetchSession
} from "../actions/dataActions";
import _ from 'lodash'
import {
useFormik
} from 'formik';
function PageFilter() {
const sessionData = useSelector(state => state.sessionData); //redux
const [filteredData, setFilteredData] = useState([]);
const formik = useFormik({
initialValues: {
date: '',
sessionType: '',
events: ''
},
onSubmit: values => {
filterData(values) //when i hit submit filter data
},
});
function filterData(values) {
let tempFilter = [];
if (values.date != '') {
sessionData.schedule_by_day.map((c, i) => {
if (c.date === values.date) {
tempFilter = [...tempFilter, c];
}
});
} else {
tempFilter = [...sessionData.schedule_by_day];
}
if (values.sessionType != '') {
tempFilter.map((c, i) => {
let tempSessionType = [];
c.session_types.map(s => {
if (parseInt(values.sessionType) == s.id) {
tempSessionType = [...tempSessionType, s]
}
});
tempFilter[i].session_types = [...tempSessionType];
//!!!!!!!
//this is a problem issue, it keeps changing my original data
//so when i call this again it's filtering from a modified SessionData
//!!!!!!!
})
} else {
}
setFilteredData([...tempFilter])
}
useEffect(() => {
dispatch(fetchSession(params.id)); //request data and updates state.sessionData
}, [])
useEffect(() => {
///when sessionData is updated filter the Data based off default form values which displays everything
if (_.isEmpty(sessionData) == false) {
filterData(formik.values)
}
}, [sessionData])
Yes, you are doing a state mutation with tempFilter[i].session_types = [...tempSessionType];. When you update any part of state you must copy it first then update the property.
It is actually rather unclear what you are really trying to do in this handler. You map a bunch of data, but don't return or save the result. It appears as though you meant to use array::forEach to issue a side-effect of pushing elements into an external array. That being said, the following is how you would/should copy the element at the specified index and create a new session_types property object reference so you are not mutating the original reference.
tempFilter[i] = {
...tempFilter[i],
session_types: [...tempSessionType],
}

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...

How do I update an array using the useContext hook?

I've set a Context, using createContext, and I want it to update an array that will be used in different components. This array will receive the data fetched from an API (via Axios).
Here is the code:
Context.js
import React, { useState } from "react";
const HeroContext = React.createContext({});
const HeroProvider = props => {
const heroInformation = {
heroesContext: [],
feedHeroes: arrayFromAPI => {
setHeroesContext(...arrayFromAPI);
console.log();
}
};
const [heroesContext, setHeroesContext] = useState(heroInformation);
return (
<HeroContext.Provider value={heroesContext}>
{props.children}
</HeroContext.Provider>
);
};
export { HeroContext, HeroProvider };
See above that I created the context, but set nothing? Is it right? I've tried setting the same name for the array and function too (heroesContex and feedHeroes, respectively).
Component.js
import React, { useContext, useEffect } from "react";
import { HeroContext } from "../../context/HeroContext";
import defaultSearch from "../../services/api";
const HeroesList = () => {
const context = useContext(HeroContext);
console.log("Just the context", context);
useEffect(() => {
defaultSearch
.get()
.then(response => context.feedHeroes(response.data.data.results))
.then(console.log("Updated heroesContext: ", context.heroesContext));
}, []);
return (
//will return something
)
In the Component.js, I'm importing the defaultSearch, that is a call to the API that fetches the data I want to push to the array.
If you run the code right now, you'll see that it will console the context of one register in the Just the context. I didn't want it... My intention here was the fetch more registers. I have no idea why it is bringing just one register.
Anyway, doing all of this things I did above, it's not populating the array, and hence I can't use the array data in another component.
Does anyone know how to solve this? Where are my errors?
The issue is that you are declaring a piece of state to store an entire context object, but you are then setting that state equal to a single destructured array.
So you're initializing heroesContext to
const heroInformation = {
heroesContext: [],
feedHeroes: arrayFromAPI => {
setHeroesContext(...arrayFromAPI);
console.log();
}
};
But then replacing it with ...arrayFromAPI.
Also, you are not spreading the array properly. You need to spread it into a new array or else it will return the values separately: setHeroesContext([...arrayFromAPI]);
I would do something like this:
const HeroContext = React.createContext({});
const HeroProvider = props => {
const [heroes, setHeroes] = useState([]);
const heroContext = {
heroesContext: heroes,
feedHeroes: arrayFromAPI => {
setHeroes([...arrayFromAPI]);
}
};
return (
<HeroContext.Provider value={heroContext}>
{props.children}
</HeroContext.Provider>
);
};
export { HeroContext, HeroProvider };

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