I've output data in json from my api formatted in a dictionary, I want a value e.g intensity0 for each frame_number. How do I do this in react js i've tried multiple things but i cant seem to get it. You can see my attempt in render part.
import "bootstrap/dist/css/bootstrap.css";
import React from "react";
import Buttons_Footer from "./components/Buttons_Footer.js";
import LeftPane from "./components/LeftPane.js"
//import './App.css';
class App extends React.Component {
constructor(props) {
super(props);
this.state = { apiResponse: "" };
}
// Comunicate with API
callAPI() {
fetch("http://localhost:9000/IntensityAPI") //React app talks to API at this url
.then(res => res.text())
.then(res => this.setState({ apiResponse: res }));
}
componentWillMount() {
this.callAPI();
}
render() {
return (
<div className="App">
<ul>
{this.state.apiResponse.map(function(item,index){
return (<div><h1>{item.frame_number}</h1></div>)
})}
</ul>
<header className="App-header">
<p></p>
<div class="row fixed-bottom no-gutters">
<div class="col-3 fixed-top fixed-bottom">
<LeftPane></LeftPane>
</div>
<div class="offset-md-3" >
</div>
</div>
</header>
</div>
);
}
}
export default App;
[{"frame_number": 1, "roi0": [101.78202823559488, 99.39509279584912, 49.546951219239915, 29.728170731543948], "intensity0": 80.0, "roi1": [101.78202823559488, 99.39509279584912, 49.546951219239915, 29.728170731543948], "intensity1": 157.0},
{"frame_number": 2, "roi0": [102.56623228630755, 97.95906005049548, 50.25603182631066, 30.153619095786393], "intensity0": 80.0, "roi1": [102.56623228630755, 97.95906005049548, 50.25603182631066, 30.153619095786393], "intensity1": 158.0},
{"frame_number": 3, "roi0": [103.39336535376313, 98.20468223716023, 49.58465295946593, 29.750791775679556], "intensity0": 80.0, "roi1": [103.39336535376313, 98.20468223716023, 49.58465295946593, 29.750791775679556], "intensity1": 157.0}, ... etc
Instead of this.state = { apiResponse: "" }; use this.state = { apiResponse: [] };
Parse data as json. Instead of .then(res => res.text()) use .then(res => res.json())
Related
In my code, the parent component is Bucket.js and the child component is the ListItem.js. The parent component makes a call to the db and gets back an object that has a structure of: [{...},{...},{...}], which will be stored into this.state.search.
When I render each child component, only the first <div> tag in <ListItem> displays. Everything after that does not render, I cannot figure out why that is the case.
Bucket.js
import React, { Component, useState } from "react";
import axios from "axios";
import ListItem from "./ListItem";
class Bucket extends Component {
constructor() {
super();
this.state = {
search: [],
};
}
componentDidMount() {
axios
.get(`http://localhost:9000/viewCribb`)
.then((response) => response)
.then((result) => {
this.setState({ search: result.data });
console.log("Search State: ", this.state);
});
}
render() {
{
console.log("Rendering!");
}
return (
<>
{this.state.search ? (
<>
{Object.keys(this.state.search).map((item, index) => (
<ListItem
{...this.props}
key={this.state.search[item].address_id}
listing={this.state.search[item]}
></ListItem>
))}
</>
) : (
<></>
)}
</>
);
}
}
export default Bucket;
ListItem.js
import React from "react";
import classNames from "classnames";
const ListItem = (...props) => {
console.log("props", props);
return (
<>
<div>{props[0].listing.streetaddress}</div>
<div className="tiles-item reveal-from-right" data-reveal-delay="200">
<div className="tiles-item-inner">
<div className="testimonial-item-content">
<p className="text-sm mb-0">{props[0].listing.streetaddress}</p>
</div>
<div className="testimonial-item-footer text-xs mt-32 mb-0 has-top-divider">
<span className="testimonial-item-name text-color-high">
Roman Level
</span>
<span className="text-color-low"> / </span>
<span className="testimonial-item-link">
<div href="#0">AppName</div>
</span>
</div>
</div>
</div>
</>
);
};
export default ListItem;
According to:
https://www.npmjs.com/package/react-axios
https://github.com/axios/axios
this might be wrong:
componentDidMount() {
axios
.get(`http://localhost:9000/viewCribb`)
.then((response) => response)
.then((result) => {
this.setState({ search: result.data });
console.log("Search State: ", this.state);
});
}
the existence of two .then to get the response feels wrong.
It seems you are following the pattern mentioned at:
https://www.digitalocean.com/community/tutorials/react-rendering-arrays-in-react
It might be a good idea if you could share the data returned through the response and compare its structure to see it it fits your needs
The problem had to do with my css, it did not get imported properly
I'm simply trying to pass props through components and render it in jsx but somehow that wouldn't work. I was searching for the problem but just cannot find it.
I'm trying pass props from this component:
import React from "react";
import "../styles/Products.css";
import ProductItem from "../items/ProductItem";
class Products extends React.Component {
constructor(props) {
super(props);
this.state = {
data: []
};
}
componentDidMount() {
fetch("../products.json")
.then(response => response.json())
.then(response => this.setState({ data: response.products }));
}
render() {
return (
<div className="products-container">
<ProductItem data={this.state.data[0]} />
</div>
);
}
}
export default Products;
to this component:
import React from "react";
import "../styles/ProductItem.css";
const ProductItem = props => {
console.log(props.data, "current");
return (
<div className="product-item">
<img src="" alt="" className="bike-image" />
<div className="active-product" />
<div className="view-details">Compare</div>
<h2>Bike</h2>
<h4>downhill bike</h4>
<p>3500 PLN</p>
</div>
);
};
export default ProductItem;
And the problem is when I'm looking in my react dev tools, props has passed properly, but when I'm trying to get to attributes of the object like props.data.id, I get an error:
Cannot read property 'id' of undefined
fetch needs some time to get the response and populate the this.state.data array. So you need to check if the this.state.data[0] value is really available or not. You can try this-
render() {
return (
<div className="products-container">
{this.state.data && this.state.data.length > 0 && <ProductItem data={this.state.data[0]} />}
</div>
);
}
I've got the following code which is looping through an JSON file from an API and loops through some posts.
import React, { Component } from 'react';
import logo from './logo.svg';
import './App.css';
//https://alligator.io/react/axios-react/
import axios from 'axios';
export default class PostList extends React.Component {
state = {
posts: []
}
componentDidMount() {
axios.get(`https://jsonplaceholder.typicode.com/users`)
.then(res => {
const posts = res.data;
this.setState({ posts });
})
}
render() {
return (
<div className="App">
<header className="App-header">
<img src={logo} className="App-logo" alt="logo" />
<h1 className="App-title">Welcome to React</h1>
</header>
<p className="App-intro">
Pulls in post slugs from Domain
</p>
<ul>
{ this.state.posts.map(post => <li>{post.name} - {post.username} </li>)}
</ul>
</div>
)
}
}
This works fine, and gets the information which was needed.
Now, in my test JSON file, the format is as follows:
https://jsonplaceholder.typicode.com/users
But in my actual JSON file from WordPress Rest API, we have another item, named core_layout:
JSON image
My issue is, trying to use the same code such as {post.name}does not get the information needed such as core_layout->image->name.
Is there an easy way around this?
Thanks all!
EDIT:
Tried the answers below, but still no luck, get the error TypeError: Cannot read property 'map' of undefined:
import React, { Component } from 'react';
import logo from './logo.svg';
import './App.css';
//https://alligator.io/react/axios-react/
import axios from 'axios';
export default class PostList extends React.Component {
state = {
posts: [],
coreLayout: {}
}
componentDidMount() {
axios.get(`https://jsonplaceholder.typicode.com/users`)
.then(res => {
// const posts = res.data;
//this.setState({ posts });
const { posts, core_layout: coreLayout } = res.data;
this.setState({ posts, coreLayout });
})
}
render() {
return (
<div className="App">
<header className="App-header">
<img src={logo} className="App-logo" alt="logo" />
<h1 className="App-title">Welcome to React</h1>
</header>
<p className="App-intro">
Pulls in post slugs from domain
</p>
<ul>
{ this.state.posts.map(post => <li>{post.name} - {post.core_layout.image.name}</li>)}
</ul>
</div>
)
}
}
EDIT 2:
Tried the below: This gets the title, but again, not the actual corelayout I need.
import React, { Component } from 'react';
class App extends Component {
constructor() {
super();
this.state = {
movies: []
}
}
componentDidMount() {
let dataURL = "http://zinsseruk.com/wp-json/wp/v2/posts?per_page=1";
fetch(dataURL)
.then(res => res.json())
.then(res => {
this.setState({
movies: res
})
})
}
render() {
let movies = this.state.movies.map((movie, index) => {
return <div key={index}>
<p><strong>Title:</strong> {movie.title.rendered}</p>
<p><strong>Title:</strong> {movie.core_layout.acf_fc_layout}</p>
</div>
});
return (
<div>
<h2>Star Wars Movies</h2>
{movies}
</div>
)
}
}
export default App;
Replace const posts = res.data; with const posts = res.data.core_layout;. Then you'll get an array similar to what you have in your test file.
I think you need to understand the JSON structure you receive from the API. Where is located core_layout property? Inside each post property as a children?
So in the posts loop you can use post.core_layout.image.name for image name, for example (and so on with other properties).
If core_property is at the root of the data you receive, you can load it inside your state like so:
state = {
posts: [],
coreLayout: {}
}
componentDidMount() {
axios.get(`https://jsonplaceholder.typicode.com/users`)
.then(res => {
// This is equivalent of doing
// const posts = res.data.posts
// const coreLayout = res.data.core_layout
const { posts, core_layout: coreLayout } = res.data;
this.setState({ posts, coreLayout });
})
}
Then use it in your code by using local component state:
render() {
...
// For example image name:
console.log('image name', this.state.coreLayout.image.name)
...
}
I am learning react and stumbled on something that seems like an absolute beginner problem. Anyway I am fetching data from an API and would like to know how to get a certain element from the JSON. I have tried different variations with [] but with no success.
JSON:
[{"name":"gfhf","id":1,"organizer":"hfgh"},{"name":"World Cup","id":2,"organizer":"FIFA"}]
React code:
import React, { Component } from "react";
import Tournaments from "./Tournaments";
const tournyAPI = 'http://localhost:8080/api/tournaments';
class template extends Component {
constructor() {
super();
this.state = {
data: [],
}
}
componentDidMount() {
fetch(tournyAPI)
.then((Response) => Response.json())
.then((findresponse) => {
console.log(findresponse)
this.setState({
data:findresponse,
})
})
}
render() {
return (
<div class="container">
<div class="row">
<div class="col-md-6 col-md-offset-3">
<div class="jumbotron text-center">
{
this.state.data.map((dynamicData, key) =>
<div>
<h1>{dynamicData.name}</h1>
</div>
)
}
</div>
</div>
</div>
</div>
);
}
}
export default template;
My goal would be to display only World cup for example.
You can filter out whatever you want from the response from the API. Like below:
Notice the line findresponse.filter(res => res.name === "World Cup");
componentDidMount() {
fetch(tournyAPI)
.then((Response) => Response.json())
.then((findresponse) => {
console.log(findresponse)
findresponse.filter(res => res.name === "World Cup");
this.setState({
data:findresponse,
})
})
}
I am calling data from coinmarketcap.com API and can not find a way to make the code auto update. I would like to get this code to update the information every 30 seconds or so.
If I call something the wrong thing... or this is a basic question, sorry this is my first week with React.
Here is what I have and it works great at loading the information from coinmarketcap.com on the when the app first loads.
Main Component (file: Crypto.jsx)
import React, { Component } from 'react';
import CryptoItem from './parts/CryptoItem';
class Crypto extends Component{
render(){
return(
<div id="CryptoItems">
<div id="data">
<CryptoItem cryptocoin="bitcoin" />
<CryptoItem cryptocoin="ethereum" />
<CryptoItem cryptocoin="ripple" />
<CryptoItem cryptocoin="iconomi" />
<CryptoItem cryptocoin="litecoin" />
<CryptoItem cryptocoin="bitcoin-cash" />
</div>
</div>
);
}
}
export default Crypto;
Child Component (file: /parts/CryptoItem.jsx)
import React, { Component } from 'react';
const urlForUsername = cryptocoin => `https://api.coinmarketcap.com/v1/ticker/${cryptocoin}/`
class CryptoItem extends Component {
constructor(props){
super(props)
this.state = {
requestFailed: false
}
}
componentDidMount(){
fetch(urlForUsername(this.props.cryptocoin))
.then(response =>{
if(!response.ok){
throw Error("Network request failed")
}
return response
})
.then(d => d.json())
.then(d => {
this.setState({
cryptoData: d[0]
})
},() => {
this.setState({
requestFailed: true
})
})
}
render() {
if(this.state.requestFailed) return <p>Failed...</p>
if(!this.state.cryptoData) return <p>Loading...</p>
return(
<ul className="CryptoItem" data-sort={ `${this.state.cryptoData.percent_change_24h}` } id={ `${this.state.cryptoData.symbol}PriceChangeID` }>
<li>
{this.state.cryptoData.name}:
</li>
<li>
$ <span id={ `${this.state.cryptoData.symbol}Price` }>{this.state.cryptoData.price_usd}</span>
</li>
<li className="PreCentChange">
<span id={ `${this.state.cryptoData.symbol}PriceChange` }>{this.state.cryptoData.percent_change_24h}</span><b>%</b>
</li>
</ul>
);
}
}
export default CryptoItem;
First, extract out the logic in componentDidMount method in child component to a separate method as below.
fetchResult = () => {
fetch(urlForUsername(this.props.cryptocoin))
.then(response =>{
if(!response.ok){
throw Error("Network request failed")
}
return response
})
.then(d => d.json())
.then(d => {
this.setState({
cryptoData: d[0]
})
},() => {
this.setState({
requestFailed: true
})
})
}
After that modify the componentDidMount method as below.
componentDidMount(){
this.fetchResult()
setInterval(this.fetchResult, 30000)
}
Note that, setInterval method can be used to execute a logic periodically. The first argument is the function which contains the logic that needs to be executed periodically. Second argument is the time interval in milliseconds.