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React props and Component

I have a problem I can not solve myself in relation to react.
What I am trying to do is add props to my Component
So I can use my compnent again and again just with a string relative to a variable so I can just write e.g.
I really searched for some different things but none that worked.
Just hoping you can get me on.
Hope it makes sense otherwise feel free to ask
My Component
import React, { Component } from "react";
export default class UserSelections extends Component {
constructor(props) {
super(props);
this.state = {
items: [],
DataisLoaded: false,
};
this.handleChange = this.handleChange.bind(this);
this.handleSubmit = this.handleSubmit.bind(this);
}
handleChange(event) {
this.setState({value: event.target.value});
}
handleSubmit(event) {
alert('Your favorite flavor is: ' + this.state.value);
event.preventDefault();
}
// ComponentDidMount is used to
// execute the code
componentDidMount() {
fetch(
"URL")
.then((res) => res.json())
.then((json) => {
this.setState({
items: json,
DataisLoaded: true
});
})
}
render() {
const { DataisLoaded, items } = this.state;
if (!DataisLoaded) return <div>
<h1> Vent et øjeblik... </h1> </div> ;
return (
<div className = "App">
<h1> Fetch data from an api in react </h1>
<form onSubmit={this.handleSubmit}>
<label><select name={this.state.slug} value={this.state.value} onChange={this.handleChange}>
{ --->Need Variable here<--- Down here
items.filter(slug => slug.slug === **'bygnings-st'**).map((item, index) => (
<option value={ item.outputvalue } key={index}>{ item.outputvalue }</option>
))
}</select>
</label>
<input type="submit" value="Submit" />
</form>
</div>
);
}
}
import React from "react";
import UserSelections from "./components/UserSelections";
import './App.css';
function App() {
return (
<div className="App">
<UserSelections **Need props here** /> <-------------------
</div>
);
}
export default App;
Best regards
Morten

If you want to pass a string as prop:
const value = "hi";
<UserSelections stringProp={value} />
And you display the value with:
{this.props.stringProp}
inside of the UserSelections component

ReactJS how to access content output from a component?

I'm currently working on a project that uses QuillJS for a rich text editor. I need to post the rich text content to my backend but I'm not sure how to access the QuillJS output.
In RichTextEditor.js
import React, { Component } from "react";
import ReactQuill from "react-quill";
import "react-quill/dist/quill.snow.css";
class RichTextEditor extends Component {
constructor(props) {
super(props);
// this.formats = formats;
this.state = { text: "" }; // You can also pass a Quill Delta here
this.handleChange = this.handleChange.bind(this);
}
handleChange(value) {
this.setState({ text: value });
const text = this.state;
console.log(text);
}
render() {
return (
<ReactQuill
value={this.state.text}
onChange={this.handleChange}
formats={this.formats}
modules={this.modules}
/>
);
}
}
export default RichTextEditor;
The console.log(text) basically just outputs the content of the rich text editor. Something like this "<p><em>aasdasdasd</em><strong><em>asdasdasdasd</em></strong></p>"
In Post.js
import React, { Component } from "react";
import RichTextEditor from "./RichTextEditor.js";
import "../../css/Post.css";
class Post extends Component {
constructor(props) {
super(props);
this.state = {
question: "",
};
}
onChange = (e) => {
this.setState({ [e.target.name]: e.target.value });
console.log(this.state);
};
handleSubmit = (e) => {
e.preventDefault();
const { question } = this.state;
console.log("Question");
console.log(question);
render() {
const { question } = this.state;
return (
<div className="post">
<div className="post__container">
<form onSubmit={this.handleSubmit}>
<div className="post__richTextEditor">
<RichTextEditor value={question} onChange={this.onChange} name="question" />
</div>
</form>
</div>
</div>
);
}
}
export default Post;
I'm trying to update the state of the question but it doesn't seem to be updating. console.log(question) only outputs a single string.
How can I access the same string output from RichTextEditor.js?

Your RichTextEditor component should not handle change, it should only receive props from higher component:
class RichTextEditor extends Component {
constructor(props) {
super(props);
}
render() {
return (
<ReactQuill
value={this.props.value}
onChange={this.props.onChange}
formats={this.formats}
modules={this.modules}
/>
);
}
}
export default RichTextEditor;
Then your Post component pass value and onChange props to RichTextEditor:
class Post extends Component {
constructor(props) {
super(props);
this.state = {
question: "",
};
this.onChange = this.onChange.bind(this);
}
onChange = (e) => {
this.setState({ [e.target.name]: e.target.value });
console.log(this.state);
};
handleSubmit = (e) => {
e.preventDefault();
const { question } = this.state;
console.log("Question");
console.log(question);
render() {
const { question } = this.state;
return (
<div className="post">
<div className="post__container">
<form onSubmit={this.handleSubmit}>
<div className="post__richTextEditor">
<RichTextEditor value={question} onChange={this.onChange} name="question" />
</div>
</form>
</div>
</div>
);
}
}

in RichTextEditor.js
handleChange(value) {
this.setState({ text: value });
const text = this.state;
console.log(text);
props.onChange(text); // passing the inner State to parent as argument to onChange handler
}
Now in Post.js
onChange = (newStateString) => {
//this.setState({ [e.target.name]: e.target.value });
console.log(newStateString); // you should get the string here
};

Pass data from input field

I want to take data from an input field and pass it into a to Generate QR code. When I pass the value as a text its work. But can’t pass the input value. Does anyone have a simple example of this working?
import React, {Component} from 'react'
import QrCode from 'react.qrcode.generator'
class DemoEdit extends Component {
constructor() {
super();
this.state = {
topicIn: "",
topicOut:""
};
this.handleChange=this.handleChange.bind(this);
this.generate=this.generate.bind(this);
}
handleChange ({ target}){
this.setState({
[target.name] : target.value
})
}
generate(){
this.setState({
topicOut:this.state.topicIn
})
}
render() {
return <div>
<input
type="text"
name="topicIn"
placeholder="Enter Text Here..."
value={this.state.topicIn}
onChange={this.handleChange}
/>
<button value="Send" onClick={this.generate}>Generate</button>
<p>{this.state.topicOut}</p>
<QrCode value={this.state.topicOut}/>
</div>
}
}
export default DemoEdit;

Use a different package. I just tried qrcode.react
import React, { Component } from "react";
import QrCode from "qrcode.react";
class DemoEdit extends Component {
constructor() {
super();
this.state = {
topicIn: ""
};
this.handleChange = this.handleChange.bind(this);
}
handleChange({ target }) {
console.log("value", target.value);
this.setState({
topicIn: `${target.value}`
});
}
render() {
return (
<div>
<input
type="text"
name="topicIn"
placeholder="Enter Text Here..."
value={this.state.topicIn}
onChange={this.handleChange}
/>
<QrCode value={this.state.topicIn} />
</div>
);
}
}
export default DemoEdit;
or as a more fancy functional component with hooks, which I totally recommend to use
import React, { useState } from "react";
import QrCode from "qrcode.react";
const DemoEdit = () => {
const [topicIn, setTopicIn] = useState("");
const onChange = (event) => setTopicIn(event.target.value);
return (
<div>
<input
type="text"
name="topicIn"
placeholder="Enter Text Here..."
value={topicIn}
onChange={onChange}
/>
<QrCode value={topicIn} />
</div>
);
};
export default DemoEdit;

Why the state is not updating in App.js after setting up this.setState?

Here is my simple to-do app program where I have made only one component which takes in the input form user and passes that input value to App.js to update items in App.js state.
todo-form.component.js
import React from 'react';
class SignInForm extends React.Component {
constructor(){
super();
this.state ={
temp: null
};
}
handleChange = (e) => {
e.preventDefault();
this.setState({
temp: e.target.value
},
console.log(this.state)
);
// this.props.addInput(e.target.value);
}
handleSubmit= (e) => {
e.preventDefault();
console.log(this.state.temp);
this.props.addInput(this.state.temp);
}
render(){
return(
<div className="container-form">
<form onSubmit={this.handleSubmit}>
<input
name="description"
type="text"
placeholder="add description"
onChange={this.handleChange}
value={this.state.input}
/>
<button type="submit">ADD</button>
</form>
</div>
);
}
}
export default SignInForm;
App.js
import React from 'react';
import './App.css';
import SignInForm from './components/todo-form/todo-form.component'
import ItemList from './components/todo-list/todo-list.component';
class App extends React.Component {
constructor(){
super();
this.state = {
input: []
};
}
addInput = (item) => {
let newInput=[...this.state.input,item];
console.log(newInput);
this.setState = ({
input: newInput
},
console.log(this.state)
);
}
render(){
return (
<div className="App">
<h1>TO-DO LIST</h1>
<SignInForm addInput={this.addInput} />
</div>
);
}
}
export default App;
On taking input the state inside todo-form.component.js is getting updated with the typed input value but on passing state.temp in handleChange function, the state inside App.js is not updating when addInput function is called.
Please help me on this issue and how my state is not getting updated in App.js??

Your setState is the problem. Have a look at my code.
App.js
class App extends React.Component {
state = {
input: [],
};
addInput = (item) => {
let newInput = [...this.state.input, item];
//setState should be this way
this.setState({
input: newInput,
});
};
render() {
return (
<div className="App">
<h1>TO-DO LIST</h1>
{this.state.input.map((el) => (
<li> {el}</li>
))}
<SignInForm addInput={this.addInput} />
</div>
);
}
}
export default App;
Login file.
class SignInForm extends React.Component {
// constructor(props) {
// super(props);
state = {
temp: null,
};
// }
handleChange = (e) => {
e.preventDefault();
this.setState({
temp: e.target.value,
});
// this.props.addInput(e.target.value);
};
handleSubmit = (e) => {
e.preventDefault();
console.log(this.state.temp);
this.props.addInput(this.state.temp);
};
render() {
return (
<div className="container-form">
<form onSubmit={this.handleSubmit}>
<input
name="description"
type="text"
placeholder="add description"
onChange={this.handleChange}
value={this.state.input}
/>
<button type="submit">ADD</button>
</form>
</div>
);
}
}
export default SignInForm;

How to handle on change for an input in reactjs?

I have a component UserInput and its used in App component(class based.) Now i am not able to render the onChange event in my html
import React from 'react';
const userInput =(props) =>{
return(
<input onChange={props.changed} />
);
};
export default userInput;
My app component looks like this.
import React, { Component } from 'react';
import './App.css';
import UserInput from './UserInput/UserInput';
import UserOutput from './UserOutput/UserOutput';
class App extends Component{
constructor(props) {
super(props);
this.state = { userName: "dssdf" };
this.handleChange = this.handleChange.bind(this);
}
const handleChange = (event) =>{
this.setState({
userName: event.target.value
})
}
render(){
return(
<div >
<UserInput changed={this.handleChange} />
<UserOutput userName={this.state.userName} />
</div>
)
}
}
export default App;
Any help is appriciated.
Thanks

pass the state as value to <input />
import React from 'react';
const userInput =(props) =>{
return(
<input value={props.value} onChange={props.changed} />
);
};
export default userInput;
class App extends Component{
constructor(props) {
super(props);
this.state = { userName: "dssdf" };
this.handleChange = this.handleChange.bind(this);
}
const handleChange = (event) =>{
this.setState({
userName: event.target.value
})
}
render(){
return(
<div >
<UserInput value={this.state.userName} changed={this.handleChange} />
<UserOutput userName={this.state.userName} />
</div>
)
}
}