Develop Reference

Is it possible to fetch/parse JSON data from one component to a different rendered/dynamic route? (React JS)

I am new to reactJS and just started learning it for a coding assignment, but I am stuck on this one problem. I created an api in a component that FETCHes photo and photo album data from the online JSON prototyping website, and I want to use that data to display on a user page (only photos and albums related to that specific user/userID). The user page is a dynamic child component of the parent component (the home page). here is what it looks like so far
This is for the JSON data. I call it apiData
import React, { Component } from "react";
class apiData extends Component {
state = {
photos: [],
albums: [],
isLoading: false
};
componentDidMount() {
this.loadData();
}
loadData = async () => {
const photos = await fetch(
"https://jsonplaceholder.typicode.com/photos"
);
const albums = await fetch(
"https://jsonplaceholder.typicode.com/albums"
);
const photoData = await photos.json();
const albumData = await albums.json();
this.setState({ isLoading: true, photos: photoData, albums: albumData});
};
render() {
return (
<div className="App">
<p> dataObject={this.state.results}</p>
</div>
);
}
}
This is the rendered/dynamic route. currently, I am using
const userPhoto = apiData.photos.find((userPhoto) =>{
to try to access the API, but I get an error that says
TypeError: Cannot read property 'find' of undefined"
(keep in mind, these 2 components are coded on the same .js file)
const userPhotoPage = ({match}) => {
const userPhoto = apiData.photos.find((userPhoto) =>{
return parseInt(match.params.id) == userPhoto.id
})
return <>
{match.isExact && <>
<h1>{userPhoto.title}</h1>
<p>image = {userPhoto.url}</p>
</>}
</>
}
I want my userPhotoPage function to successfully access the data from apiData, so I can manipulate it and add data to the photo page, but I'm not sure if this is possible? If I need to provide more information I'll gladly give it!

It looks like your trying to access the find method on an undefined object. First off, the .find() method is an iterator on arrays. I tried fetching the data from your JSON photos API but for some reason, it's hanging on this end. I'm not sure if that API actually returns an array. I would look into that first. Next, even if it returns an array and your able to chain the find method on it you're still left with the issue of function scope. The photo objects is scoped to/private your loadData async funtion. You will not be able to access it outside of the function.

Fetch one JSON object and use it reactjs

I'm very new to JS and ReactJS and I try to fetch an endpoint which gives me a JSON Object like this :
{"IDPRODUCT":4317892,"DESCRIPTION":"Some product of the store"}
I get this JSON Object by this endpoint :
http://localhost:3000/product/4317892
But I dont how to use it in my react application, I want to use those datas to display them on the page
My current code looks like this but it's not working and I'm sure not good too :
import React, {Component} from 'react';
class Products extends Component {
constructor(props){
super(props);
this.state = {
posts: {}
};
};
componentWillMount() {
fetch('http://localhost:3000/product/4317892')
.then(res => res.json())
.then(res => {
this.setState({
res
})
})
.catch((error => {
console.error(error);
}));
}
render() {
console.log(this.state)
const { postItems } = this.state;
return (
<div>
{postItems}
</div>
);
}
}
export default Products;
In the console.log(this.state) there is the data, but I'm so confused right now, dont know what to do
Since I'm here, I have one more question, I want to have an input in my App.js where the user will be able to type the product's id and get one, how can I manage to do that ? Passing the data from App.js to Products.js which is going to get the data and display them
Thank you all in advance

Your state doesn't have a postItems property which is considered undefined and react therefore would not render. In your situation there is no need to define a new const and use the state directly.
Also, when you setState(), you need to tell it which state property it should set the value to.
componentWillMount() {
fetch('http://localhost:3000/product/4317892')
.then(res => res.json())
.then(res => {
this.setState({
...this.state, // Not required but just a heads up on using mutation
posts: res
})
})
.catch((error => {
console.error(error);
}));
}
render() {
console.log(this.state)
return (
<div>
<p><strong>Id: {this.state.posts.IDPRODUCT}</strong></p>
<p>Description: {this.state.posts.DESCRIPTION}</p>
</div>
);
}

I have got 3 names for the same thing in your js: posts, postItems and res.
React can not determine for you that posts = postItems = res.
So make changes like this:
-
this.state = {
postItems: {}
};
-
this.setState({
postItems: res
});
-
return (
<div>
{JSON.stringify(postItems)}
<div>
<span>{postItems.IDPRODUCT}</span>
<span>{postItems.DESCRIPTION}</span>
</div>
</div>
);

{postItems["IDPRODUCT"]}
Will display the first value. You can do the same for the other value. Alternatively, you can put
{JSON.stringify(postItems)}
With respect to taking input in the App to use in this component, you can pass that input down through the props and access it in this component via this.props.myInput. In your app it'll look like this:
<Products myInput={someInput} />

Access query inside return method

I have a backend Drupal site and react-native app as my frontend. I am doing a graphQL query from the app and was able to display the content/s in console.log. However, my goal is to use a call that query inside render return method and display it in the app but no luck. Notice, I have another REST API call testName and is displaying in the app already. My main concern is how to display the graphQL query in the app.
Below is my actual implementation but removed some lines.
...
import gql from 'graphql-tag';
import ApolloClient from 'apollo-boost';
const client = new ApolloClient({
uri: 'http://192.168.254.105:8080/graphql'
});
client.query({
query: gql`
query {
paragraphQuery {
count
entities {
entityId
...on ParagraphTradingPlatform {
fieldName
fieldAddress
}
}
}
}
`,
})
.then(data => {
console.log('dataQuery', data.data.paragraphQuery.entities) // Successfully display query contents in web console log
})
.catch(error => console.error(error));
const testRow = ({
testName = '', dataQuery // dataQuery im trying to display in the app
}) => (
<View>
<View>
<Text>{testName}</Text> // This is another REST api call.
</View>
<View>
<Text>{dataQuery}</Text>
</View>
</View>
)
testRow.propTypes = {
testName: PropTypes.string
}
class _TestSubscription extends Component {
...
render () {
return (
<View>
<FlatList
data={this.props.testList}
...
renderItem={
({ item }) => (
<testRow
testName={item.field_testNameX[0].value}
dataQuery={this.props.data.data.paragraphQuery.entities.map((dataQuery) => <key={dataQuery.entityId}>{dataQuery})} // Here I want to call the query contents but not sure how to do it
/>
)}
/>
</View>
)
}
}
const mapStateToProps = (state, ownProps) => {
return ({
testList: state.test && state.test.items,
PreferredTest: state.test && state.test.PreferredTest
})
}
...

There are few different things that are wrong there.
Syntax error is because your <key> tag is not properly closed here:
(dataQuery) => <key={dataQuery.entityId}>{dataQuery})
And... there is no <key> element for React Native. You can check at docs Components section what components are supported. Btw there is no such an element for React also.
Requesting data is async. So when you send request in render() this method finishes execution much earlier before data is returned. You just cannot do that way. What can you do instead? You should request data(in this element or its parent or Redux reducer - it does not matter) and after getting results you need to set state with .setState(if it happens inside the component) or .dispatch(if you are using Redux). This will call render() and component will be updated with data retrieved. There is additional question about displaying spinner or using other approach to let user know data is still loading. But it's orthogonal question. Just to let you know.
Even if requesting data was sync somehow(for example reading data from LocalStorage) you must not ever do this in render().This method is called much more frequently that you can expect so making anything heavy here will lead to significant performance degradation.
So having #3 and #4 in mind you should run data loading/fetching in componentDidMount(), componentDidUpdate() or as a part of handling say button click.

How do I create an array after Axios response and Display it in React js

I am having trouble creating an array of titles from an Axios response. The method getTitles(props) receives data from the Axios response. How do I create an array of titles dynamically?
The functions I have tried in Javascript are for loops and EC6 mapping, nothing seems to work. Being new to react I could be missing something but I am not sure what it is.
React code
export default class Featured extends React.Component {
constructor() {
super();
this.state = {
data: null,
}
}
/**
* Received request from server
*/
componentDidMount(){
ApiCalls.articleData()
.then(function(data){
this.setState(function(){
return {
data: data
}
})
}.bind(this));
}
getTitles(props){
//-- What code do I place here?
console.log(props.data)
return ['test title', 'test title 2'];
}
/**
* Render request
*/
render() {
let dataResponse = JSON.stringify(this.state.data, null, 2);
const Articles = this.getTitles(this.state).map((title, i) => <Article key={i} title={title}/> );
return (
<div class="row">{Articles}
<pre>{dataResponse}</pre>
</div>
);
}
}
Axios Code
var ApiCalls = {
articleData: function(id){
return axios.all([getArticles(id)])
.then(function(arr){
return arr[0].data.data;
})
.catch(function (error) {
console.log(error);
})
},

React setState behaves asynchronously . Your articles get rendered before the ajax was called and was not re rendered due to asynchrony in setState.
This is what doc(https://reactjs.org/docs/react-component.html#setstate) says
setState() does not always immediately update the component. It may batch or defer the update until later. This makes reading this.state right after calling setState() a potential pitfall. Instead, use componentDidUpdate or a setState callback (setState(updater, callback)), either of which are guaranteed to fire after the update has been applied. If you need to set the state based on the previous state, read about the updater argument below.
You can render the article after successful ajax call like below
componentDidMount(){
ApiCalls.articleData()
.then(function(data){
render(<Article data={data}/>, document.getElementById('...'));
}.bind(this));
}

Because of the post above, I was able to fix the issue by the code example below To see a working example goto the git repo
ApiCalls.articleData()
.then(function(data){
const newData = data.map(c => {
return c.attributes.title;
})
const addElement = newData.map((title, i) => <ContentTiles key={i} title={title}/> );
const newState = Object.assign({}, this.state, {
newData: addElement
});
this.setState(newState);
}.bind(this));

Accessing data from Axios GET request

I'm having trouble accessing data from an Axios GET request. I'd like to be able to iterate through all of the data I get and create a table that displays the username, avatar, and score for each user. The only way I'm able to currently render a single username is with the following code:
this.setState({name: res.data[0].username});
But the above code only gives me access to the first object in the URL I use in the GET request. If I use this code:
this.setState({name: JSON.stringify(res.data)});
I'm able to render the entire object as a string. So that makes me think I need to update my render method, but I'm not sure how.
What steps should I take so that I can map over the state that I'm setting and render each user's data in a table or list?
class LeaderBoard extends React.Component {
constructor(props) {
super(props)
this.state = {
name: []
}
}
componentDidMount(){
axios.get('https://fcctop100.herokuapp.com/api/fccusers/top/recent').then(res =>
{
this.setState({name: res.data[0].username});
});
}
render () {
return (
<div>
<h1>{this.state.name}</h1>
</div>
)
}
}
ReactDOM.render(
<LeaderBoard/>, document.getElementById("app"));

You're on the right track, you're just missing a few key pieces.
Step 1: Add the entire array to your state
I'm not sure of the exact structure of your data, but you likely want to do this
componentDidMount(){
axios.get('https://fcctop100.herokuapp.com/api/fccusers/top/recent').then(res =>
{
this.setState({data: res.data});
});
}
Now you have all the data you want to work with in your state, ready to be iterated over.
Step 2: Use .map() to create the JSX elements you want
This code here:
render () {
return (
<div>
<h1>{this.state.name}</h1>
</div>
)
}
}
The big fault here is that it will only ever render one thing, because, well, that's all there is. What you want to do is .map() through and create a bunch of names from your data, right?
That would look more like this.
render () {
const namesToRender = this.state.data.map(val => {
return (
<h1>val.username</h1>
)
})
return (
<div>
{namesToRender}
</div>
)
}
}
All this is saying is "Go through that data and give me the name of each person and wrap it in some <h1> tags and spit that out".