Develop Reference

Get prop value from div in React

A working example of my problem can be found at:
https://codepen.io/RyanCRickert/pen/vYYQeaW
I am prop drilling a function two levels and passing that function along with an index to a rendered component. When a name is submitted it renders a new component which shows the name and div which has an onClick (X). I am trying to receive the index of where the name is located in the array which it lives so that I may splice it out when the button is clicked.
If I enter the name "Bob" for example, then click the div with the listener I can console log the event.target. Using the above example I get "<div class='person-item__X' value='0'>X</div>" for event.target and undefined for event.target.value. The value is being assigned as <div onClick={props.removeName} class="person-item__X" value={props.value}>X</div>.
Am I just unable to grab the value of a div in such a manor? Or is there something that I am missing? Thank you

Change these to your code
const PersonListItem = props => (
<div class="person-item">
<div class="person-item__name">{props.name}</div>
<div onClick={() => props.removeName(props.value)} class="person-item__X" value={props.value}>X</div>
</div>
);
Inside PeopleList replace this line
<PersonListItem key={index} name={person} value={index} removeName={(id) => props.removeName(id)} />
Inside TeamGenerator replace this line
<PeopleList people={this.state.names} removeName={(id) => this.handleRemoveName(id)} />
now in handleRemoveName you will recieve a id of the item on which X was clicked
handleRemoveName = id => {
const currentArr = this.state.names;
console.log(id);
}

In your case, to grab the value inside this div, you should use ref API.
Your code should look like this:
TeamGenerator.js
import React, { Component } from "react";
import CustomModal from "./Modal";
import PeopleList from "./PeopleList";
import "./index.css";
export default class App extends Component {
constructor(props) {
super(props);
// Create a ref
this.divTextRef = React.createRef();
this.state = {
names: [],
selectedName: ""
};
}
handleCloseModal = () => {
this.setState({
selectedName: ""
});
};
handleChange = e => {
this.setState({ name: e.target.value });
};
handleRemoveName = index => {
// Get your name and index this way
console.log("Your text: ", this.divTextRef.current.innerHTML);
console.log("Your index: ", index);
};
handleSubmit = e => {
e.preventDefault();
const currentNames = this.state.names;
if (this.state.name)
currentNames.push(
this.state.name[0].toUpperCase() + this.state.name.slice(1)
);
this.setState({
name: "",
names: currentNames
});
};
render() {
return (
<div className="container">
<CustomModal
selectedName={this.state.selectedName}
closeModal={this.handleCloseModal}
/>
<form onSubmit={this.handleSubmit}>
<label>
Add name:
<input
type="text"
value={this.state.name}
onChange={this.handleChange}
/>
</label>
<input type="submit" value="Submit" />
</form>
<div className="people-list-container">
<PeopleList
people={this.state.names}
removeName={this.handleRemoveName}
upperRef={this.divTextRef} // Pass the ref down from your Component tree
/>
</div>
</div>
);
}
}
PeopleList.js
import React from "react";
import PersonListItem from "./PersonListItem";
export default class PeopleList extends React.Component {
render() {
return (
<div className="people-container">
<div className="people-title">List of people</div>
<div className="people-list">
{this.props.people.length === 0 ? (
<div className="people-item">
<span>No people added</span>
</div>
) : (
this.props.people.map((person, index) => (
<PersonListItem
key={index}
name={person}
value={index}
removeName={() => this.props.removeName(index)} // Passing index to the removeName function of Parent
upperRef={this.props.upperRef} // Continue passing it down to PersonListItem
/>
))
)}
</div>
</div>
);
}
}
PersonListItem.js
import React from "react";
const PersonListItem = props => (
<div className="person-item">
<div ref={props.upperRef} className="person-item__name"> // Use the passed ref
{props.name}
</div>
<div
onClick={props.removeName}
className="person-item__X"
value={props.value}
>
X
</div>
</div>
);
export default PersonListItem;
The div node does not have the value like input, so you can not grab it by your old way.

Not rendering JSX from function in React

The function is getting the value of a button click as props. Data is mapped through to compare that button value to a key in the Data JSON called 'classes'. I am getting all the data correctly. All my console.logs are returning correct values. But for some reason, I cannot render anything.
I've tried to add two return statements. It is not even rendering the p tag with the word 'TEST'. Am I missing something? I have included a Code Sandbox: https://codesandbox.io/s/react-example-8xxih
When I click on the Math button, for example, I want to show the two teachers who teach Math as two bubbles below the buttons.
All the data is loading. Just having an issue with rendering it.
function ShowBubbles(props){
console.log('VALUE', props.target.value)
return (
<div id='bubbles-container'>
<p>TEST</p>
{Data.map((item,index) =>{
if(props.target.value == (Data[index].classes)){
return (
<Bubble key={index} nodeName={Data[index].name}>{Data[index].name}
</Bubble>
)
}
})}
</div>
)
}

Sandbox Link: https://codesandbox.io/embed/react-example-m1880
import React, {Component} from 'react';
import ReactDOM from 'react-dom';
const circleStyle = {
width: 100,
height: 100,
borderRadius: 50,
fontSize: 30,
color: "blue"
};
const Data = [
{
classes: ["Math"],
name: "Mr.Rockow",
id: "135"
},
{
classes: ["English"],
name: "Mrs.Nicastro",
id: "358"
},
{
classes: ["Chemistry"],
name: "Mr.Bloomberg",
id: "405"
},
{
classes: ["Math"],
name: "Mr.Jennings",
id: "293"
}
];
const Bubble = item => {
let {name} = item.children.singleItem;
return (
<div style={circleStyle} onClick={()=>{console.log(name)}}>
<p>{item.children.singleItem.name}</p>
</div>
);
};
function ShowBubbles(props) {
var final = [];
Data.map((item, index) => {
if (props.target.value == Data[index].classes) {
final.push(Data[index])
}
})
return final;
}
function DisplayBubbles(singleItem) {
return <Bubble>{singleItem}</Bubble>
}
class Sidebar extends Component {
constructor(props) {
super(props);
this.state = {
json: [],
classesArray: [],
displayBubble: true
};
this.showNode = this.showNode.bind(this);
}
componentDidMount() {
const newArray = [];
Data.map((item, index) => {
let classPlaceholder = Data[index].classes.toString();
if (newArray.indexOf(classPlaceholder) == -1) {
newArray.push(classPlaceholder);
}
// console.log('newArray', newArray)
});
this.setState({
json: Data,
classesArray: newArray
});
}
showNode(props) {
this.setState({
displayBubble: true
});
if (this.state.displayBubble === true) {
var output = ShowBubbles(props);
this.setState({output})
}
}
render() {
return (
<div>
{/* {this.state.displayBubble ? <ShowBubbles/> : ''} */}
<div id="sidebar-container">
<h1 className="sidebar-title">Classes At School</h1>
<h3>Classes To Search</h3>
{this.state.classesArray.map((item, index) => {
return (
<button
onClick={this.showNode}
className="btn-sidebar"
key={index}
value={this.state.classesArray[index]}
>
{this.state.classesArray[index]}
</button>
);
})}
</div>
{this.state.output && this.state.output.map(item=><DisplayBubbles singleItem={item}/>)}
</div>
);
}
}
ReactDOM.render(<Sidebar />, document.getElementById("root"));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.0.0/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.0.0/umd/react-dom.production.min.js"></script>
<div id="root"></div>

The issue here is ShowBubbles is not being rendered into the DOM, instead (according the sandbox), ShowBubbles (a React component) is being directly called in onClick button handlers. While you can technically do this, calling a component from a function will result in JSX, essentially, and you would need to manually insert this into the DOM.
Taking this approach is not very React-y, and there is usually a simpler way to approach this. One such approach would be to call the ShowBubbles directly from another React component, e.g. after your buttons using something like:
<ShowBubbles property1={prop1Value} <etc...> />
There are some other issues with the code (at least from the sandbox) that you will need to work out, but this will at least help get you moving in the right direction.

Push dynamically added html list item into last array

How can i push html into the last array. I was trying to add an item and supposed be add instantly into list array. The cod is working except I'm struggling to add new list into last array.
function addItem(id,name){
const array = JSON.parse(localStorage.getItem('categories'));
array.push({
name: name,
id:id,
});
//<li>{name}</li> push this into last array
localStorage.setItem('categories',JSON.stringify(array));
}
{categories.map(function(item, key){
return <div>
<ul>
<li>item.name</li>
</ul>
<button onClick={() => addItem(item.id,'value name')}>Add</button>
</div>
})}

Something looks wrong in your example. I have added a complete exampl. You can maintain localStorage and State both. I hope this example helps you.
You mistake is that while adding new item you are pushing it to localStoage due to which react dom does not get rerendered. You have to update the value of state for that.
class App extends React.Component {
constructor() {
super();
this.state = {
categories: [
{
name: "Hello",
id: 1
},
{
name: "World",
id: 2
}
]
};
this.addItem = this.addItem.bind(this);
this.SaveToLocalStorage = this.SaveToLocalStorage.bind(this);
}
SaveToLocalStorage() {
const categories = this.state.categories;
localStorage.setItem("categories", JSON.stringify(categories));
}
addItem(id, name) {
const categories = this.state.categories;
categories.push({
name: name,
id: id
});
this.setState({ categories });
//localStorage.setItem("categories", JSON.stringify(categories));
}
render() {
let categories = this.state.categories;
const test = categories.map(item => (
<div key={item.id}>
<li>{item.name}</li>
</div>
));
return (
<div>
{test}
<button onClick={() => this.addItem(Date.now(), "Item")}>
Click to Add More
</button>
<button onClick={() => this.SaveToLocalStorage()}>
Save To LocalStorage{" "}
</button>
</div>
);
}
}
ReactDOM.render( < App / > , document.getElementById("root"));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>

I guess this is what you are asking for. You just need to set it to state and re-render it when ever you are trying to add an element to list/array. I don't know why you are setting it to local storage but you can do it from state directly if your intention is to just store the previous array for future additions.
import React, { Component } from "react";
class App extends Component {
state = {};
constructor(props){
super(props);
this.state={
arr = []
}
}
addItem(id, name) {
const array = JSON.parse(localStorage.getItem("categories"));
array.push({
name: name,
id: id
});
//<li>{name}</li> push this into last array
localStorage.setItem("categories", JSON.stringify(array));
this.setState({arr:array});
}
renderList = () => {
return this.state.array.map(function(item, key) {
return (
<div>
<ul>
<li>item.name</li>
</ul>
<button onClick={() => addItem(item.id, "value name")}>Add</button>
</div>
);
});
};
render() {
return <div>{this.renderList()}</div>;
}
}
export default App;

React: How to display a default object and highlight li bold?

I am fairly new to React and was wondering if anybody could give me an insight on a problem I am stuck with.
Right now I have a parent(Hello.js) component and two children(Mixer.js and renderCont.js) at the same level.
I am trying to render a list in the Mixer.js and display its corresponding objects in the Hello.js through by passing the values into RenderCont.js. I've gotten to a point where nothing is displayed before I click on any of the list to pass on a object.
From here is where I am stuck: I want the first object of the list to be displayed as a default, at the same time bold the first in the list. And then execute the as I have below.
This is my first time posting a question on stackoverflow so I'm not sure if my question makes sense with the attached codes but I will greatly appreciate any kind of support.
Parent Hello.js:
import React, { Component } from 'react';
import RenderCont from './renderCont.js';
import Mixer from './Mixer';
class Hello extends Component{
constructor(props) {
super(props);
this.state = {
items: [{
id: 0,
name: "First",
background: "white"
}, {
id: 1,
name: "Second",
background: "yellow"
}, {
id: 2,
name: "Third",
background: "blue"
}],
selectedItem: 0
}
this.handle = this.handle.bind(this)
}
handle(value) {
// console.log(this.state.selectedItem);
this.setState({
selectedItem: value
})
}
render() {
const list = this.state.items.map((item) => {
return(item);
})
return (
<div>
<Mixer item={list} onClick={this.handle} selected={this.state.selectedItem}/>
<ul id = "todo" >
<RenderCont item={this.state.selectedItem}/>
</ul>
</div>
)
}
}
export default Hello;
Mixer.js Child1:
import React, { Component } from 'react';
class Mixer extends Component{
constructor(props) {
super(props);
this.state = {
}
this.handleClick = this.handleClick.bind(this);
}
handleClick(item){
this.props.onClick(item);
}
renderTodos(propItems) {
return (
<div>
{propItems.map((item) => (
<li className={this.props.selected === item ? 'media clicked' : 'media'}
key={item.id} onClick = {() => this.handleClick(item)}>
{item.name}
</li>
))}
</div>
)
}
render() {
return (
<div className="yoyoyo">
{this.renderTodos(this.props.item)}
</div>
)
}
}
export default Mixer;
Second Child Comp renderCont.js :
import React, { Component } from 'react';
class RenderCont extends Component{
constructor(props) {
super(props);
}
renderBox(item){
return(
<div style={{color:item.background}}>
{item.id}
{item.name}
</div>
)
}
render() {
return (
<div className="yoyo">
{this.renderBox(this.props.item)}
</div>
)
}
}
export default RenderCont;
and the CSS:
.yoyo{
left: 500px;
background-color:red;
width:500px;
height:500px;
}
.media{
color: black;
}
.clicked{
font-weight: 900;
}
.yoyoyo{
background-color:lightblue;
width:200px;
height:200px;
}

I think the problem is some mismatch between the initial and eventual value of this.props.selected in Mixer.js. You initially set this.state.selectedItem = 0, and this is what is initially passed as the selected prop to Mixer. But the test you apply in that component is
this.props.selected === item ?
While there is one item.id that === 0, there is never an item that === 0. So no items are highlighted at first. But then, once an item is clicked and selectedItem is actually set to an item, the entry is made bold.
So it looks like you need to either make your initial selection equal to the item.id === 0 reference, or consistently refer to items within your components by their id's.

Getting value from react component

I have a component InputArea with state = {input: ''}
Then I map several of these components in a container and write them in state = {inputAreas: []}
Now, how can I get inputs in the container? Logging this.state.inputAreas[0] returns object like this:
{$$typeof: Symbol(react.element), type: ƒ, key: "1", ref: null, props:
{…}, …}
In elements it shows like this:
<input type="text" class="form-control" name="input" value="abc">
Using this.state.prefooterArea[0].value gives undefined.
I also tried passing input from component to container as props, but it says getInput is not a function. From what I understood it has something to do with the fact I used map in the container. I can't use redux in this project.
Code of component
class PrefooterAreaInput extends Component {
state = {
input: ''
}
textChangedHandler = (event) => {
let newState = {};
newState[event.target.name] = event.target.value;
this.setState(newState);
}
render() {
return (
<div>
<input
className="form-control"
type="text"
name="input"
value = {this.state.input}
onChange={this.textChangedHandler}
/>
</div>
)
}
}
Code of container
class DescriptionFrame extends Component {
state = {,
prefooterArea: [<PrefooterAreaInput key={1}/>]
};
addFooterInputHandler = event => {
event.preventDefault();
if (this.state.prefooterArea.length < prefooterInputFieldsMax) {
var newPrefooterArea = this.state.prefooterArea.map(
inputField => inputField
);
newPrefooterArea.push(
<PrefooterAreaInput key={this.state.prefooterArea.length + 1} />
);
this.setState({ prefooterArea: newPrefooterArea });
}
};
removeFooterInputHandler = event => {
event.preventDefault();
if (this.state.prefooterArea.length > 1) {
var newPrefooterArea = this.state.prefooterArea.map(
inputField => inputField
);
newPrefooterArea.splice(newPrefooterArea.length - 1);
this.setState({ prefooterArea: newPrefooterArea });
}
render() {
// want to get this.state.prefooterArea[0]'s value
return (
<div>
{this.state.prefooterArea}
<a
className="nav-link"
href=""
onClick={this.addFooterInputHandler}
>
Add More
</a>
<a
className="nav-link"
href=""
onClick={this.removeFooterInputHandler}
>
Remove Last
</a>
</div>
);
}
}

Figured it out. This caused problem.
prefooterArea: [<PrefooterAreaInput key={1}/>]
I should have added that initial PrefooterAreaInput with lifecycle method instead. With that I was able to pass state just fine.

Are you trying to achieve something like this ?
child component :
export default class InputBox extends React.Component {
render() {
return (
<input onChange={event => this.props.onChange(event.target.value)} />
);
}}
parent component :
import InputBox from './InputBox';
class FilterBar extends React.Component {
constructor(props) {
super(props);
this.state = {
inputs: "" //get input value from state this input
};
this.updateFilters = this.updateFilters.bind(this);
}
updateFilters(i) {
this.setState({ inputs: i }); // this will print whatever input you type
}
render() {
return (
<div>
<InputBox onChange={(i) => this.updateFilters(i)} />
</div>
);
}
}