React.js Increment and Decrement counter not mapping correctly

React.js Increment and Decrement counter not mapping correctly - javascript

Let me preface that I'm in the process of learning React and I'm still pretty green at this.
I'm going to give the necessary parts of the code:
I have built a counter with increment and decrement buttons that are utilized by ways of state, they work just fine until I introduce and array and map over it. Then things start to break down. I know my code is wrong, I know there's something amiss however I'm completely ignorant as to what to even look for.
In my counting.js I have:
const players = [
{
name: "Jon Smith",
score: 10,
id: 1,
},
{
name: "Jon Doe",
score: 40,
id: 2,
},
{
name: "John Ham",
score: 30,
id: 3,
},
];
Which I have mapped in here:
class Counting extends React.Component {
constructor(props) {
super(props);
this.state = {
count: 0,
nameof: 'Full Name',
}
this.incrementCount = this.incrementCount.bind(this)
this.decrementCount = this.decrementCount.bind(this)
}
incrementCount(e) {
this.setState({
count: (this.state.count + 1),
})
}
decrementCount(e) {
this.setState({
count: (this.state.count - 1),
})
}
render() {
const listPlayers = players.map((players) =>
<Counter
key={players.id}
incrementCount={this.incrementCount}
decrementCount={this.decrementCount}
nameof={players.name}
count={players.score}
/>
);
return (
<div className="wrap">
<Titles header="Counter" subhead="A setState() project" subtitle="this will change" />
<h3>This doesn't work correctly</h3>
<ul>{listPlayers}</ul>
<ScoreList>
<h3> works</h3>
<li>
<Counter
incrementCount={this.incrementCount}
decrementCount={this.decrementCount}
nameof={this.state.nameof}
count={this.state.count}
/>
</li>
<li>
<Counter
incrementCount={this.incrementCount}
decrementCount={this.decrementCount}
nameof={this.state.nameof}
count={this.state.count}
/>
</li>
</ScoreList>
</div>
)
}
}
I have imported my Counter.jswhich is comprised of:
class Counter extends Component {
render() {
const { count } = this.props
const { decrementCount } = this.props
const { incrementCount } = this.props
const { nameof } = this.props
return (
<div>
<CountCell>
<Row style={{alignItems: 'center'}}>
<Col>
<CountButton
onClick={incrementCount}>
<Icon
name="icon" className="fa fa-plus score-icon"
/>
</CountButton>
</Col>
<Col >
<ScoreName>{nameof}</ScoreName>
</Col>
<Col >
<Score>{count}</Score>
</Col>
<Col>
<CountButton
onClick={decrementCount}>
<Icon
name="icon" className="fa fa-minus score-icon"
/>
</CountButton>
</Col>
</Row>
</CountCell>
</div>
)
}
}
So the increment and decrement buttons are only working globally and only for my static <li>, not my ones generated from the array. If I'm making any sense at all, how do I individually map my inc/dec buttons to each <li> and not globally?
Thank you!

You need to keep the state also be an array of objects, each storing data for a corresponding user
class Counting extends React.Component {
constructor(props) {
super(props);
this.state = {
countInfo: []
}
this.incrementCount = this.incrementCount.bind(this)
this.decrementCount = this.decrementCount.bind(this)
}
incrementCount(index) {
var countInfo = [...this.state.countInfo];
if(countInfo[index]) {
countInfo[index].count = countInfo[index].count + 1
countInfo[index].nameOf = players[index].name
}
else {
countInfo[index] = {count: 1, nameOf: players[index].name}
}
this.setState({
countInfo
})
}
decrementCount(index) {
var countInfo = [...this.state.countInfo];
if(countInfo[index]) {
countInfo[index].count = countInfo[index].count - 1
countInfo[index].nameOf = players[index].name
}
else {
countInfo[index] = {count: -1, nameOf: players[index].name}
}
this.setState({
countInfo
})
}
render() {
const listPlayers = players.map((players, index) =>
<Counter
key={players.id}
incrementCount={() => this.incrementCount(index)}
decrementCount={() => this.decrementCount(index)}
nameof={players.name}
count={players.score}
/>
);
return (
<div className="wrap">
<Titles header="Counter" subhead="A setState() project" subtitle="this will change" />
<h3>This doesn't work correctly</h3>
<ul>{listPlayers}</ul>

Related

How to make a simple loop slider in the React?

Sorry for my English)
Do not judge strictly, since I just started working with the react.
I made a simple slider on the react and now I want to make it cyclic.
But I can’t. In my code it seems to be cyclic, but for some reason it skips the last picture.
how can i fix it?
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
data: [
{
id: 1,
name: "Product 1",
price: 50,
q: 0,
category: "Sporting Goods",
images: [
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property04.jpg",
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property02.jpg",
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property01.jpg",
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property03.jpg"
],
currentImageIndex: 0,
isCycleMode: false,
cantGoPrev: false,
cantGoNext: true
},
{
id: 2,
name: "Product 2",
price: 70,
q: 0,
category: "Sporting Goods",
images: [
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property04.jpg",
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property02.jpg",
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property01.jpg",
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property03.jpg",
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property02.jpg",
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property01.jpg",
"https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property03.jpg"
],
currentImageIndex: 0,
isCycleMode: false,
cantGoPrev: false,
cantGoNext: true
}
]
};
}
nextSlideHandler = (e, item, index ) => {
let arr = [...this.state.data];
let newIndex = this.state.data[index].currentImageIndex;
if (e.currentTarget.dataset.direction === "next") {
if (newIndex < this.state.data[index].images.length - 1) {
newIndex = this.state.data[index].currentImageIndex + 1;
arr[index].cantGoPrev = true;
this.setState({data:arr})
}
if (newIndex === this.state.data[index].images.length - 1) {
newIndex = 0;
arr[index].cantGoNext = true;
this.setState({data:arr})
}
} else {
if (newIndex > 0) {
newIndex = this.state.data[index].currentImageIndex - 1;
arr[index].cantGoNext = true;
this.setState({data:arr})
}
if (newIndex === 0) {
arr[index].cantGoPrev = false;
this.setState({data:arr})
}
}
arr[index].currentImageIndex = newIndex;
this.setState({ data:arr });
}
render() {
return (
<div className="App">
<div>
<h3>Products</h3>
<div className="collection">
{this.state.data.map((item, index) => (
<div key={item.id} className="product">
<div className="product__image">
<div>
<button
disabled={!item.cantGoPrev}
data-direction="prev"
onClick={(e)=> this.nextSlideHandler(e,item, index)}
className="prev"
>
prev
</button>
</div>
<div>
<img
src={item.images[item.currentImageIndex]}
alt=""
/>
{item.images.currentImageIndex}
</div>
<div>
<button
disabled={!item.cantGoNext}
data-direction="next"
onClick={(e)=> this.nextSlideHandler(e, item, index)}
className="next"
>
next
</button>
</div>
</div>
<div className="product__name">{item.name}</div>
<div className="product__price">{item.price}</div>
</div>
))}
</div>
</div>
</div>
);
}
}
What is the best way to write a slider?
I will be glad of any help

First: There are many ways to achieve what you are trying to do, but this is how I would have done it.
Instead of using index to update different state, I would make a own component for Product. Inside that component you have full access to that products state and props. This makes it easier to work with the correct data.
I would also remove the next/previous-logic from the state and just do a check if the buttons should be active on render.
class App extends React.Component {
constructor (props) {
super(props)
this.state = {
data: [
{
id: 1,
name: 'Product 1',
price: 50,
q: 0,
category: 'Sporting Goods',
images: [
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property04.jpg',
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property02.jpg',
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property01.jpg',
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property03.jpg'
],
currentImageIndex: 0,
isCycleMode: false
},
{
id: 2,
name: 'Product 2',
price: 70,
q: 0,
category: 'Sporting Goods',
images: [
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property04.jpg',
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property02.jpg',
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property01.jpg',
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property03.jpg',
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property02.jpg',
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property01.jpg',
'https://ihatetomatoes.net/demos/_rw/01-real-estate/tn_property03.jpg'
],
currentImageIndex: 0,
isCycleMode: false
}
]
}
}
handleChange = (arr) => {
// State updates based on other state should be asynchronous
// https://reactjs.org/docs/state-and-lifecycle.html#state-updates-may-be-asynchronous
this.setState((state, props) => {
const oldArr = [...state.data]
const arrIndex = oldArr.findIndex(x => x.id === arr.id)
oldArr[arrIndex] = arr
return ({
data: oldArr
})
})
}
render () {
return (
<div className='App'>
<div>
<h3>Products</h3>
<div className='collection'>
{this.state.data.map((item) => (
<Product
item={item}
key={item.id}
onChange={this.handleChange}
/>
))}
</div>
</div>
</div>
)
}
}
class Product extends React.Component {
handleSlideChange = (e) => {
const arr = { ...this.props.item }
if (e.currentTarget.dataset.direction === 'next') {
arr.currentImageIndex++
} else {
arr.currentImageIndex--
}
this.props.onChange(arr)
};
render () {
const { item } = this.props
return (
<div key={item.id} className='product'>
<div className='product__image'>
<div>
<button
disabled={item.currentImageIndex <= 0}
data-direction='prev'
onClick={this.handleSlideChange}
className='prev'
>
Prev
</button>
</div>
<div>
<img src={item.images[item.currentImageIndex]} alt='' />
{item.images.currentImageIndex}
</div>
<div>
<button
disabled={item.currentImageIndex >= item.images.length - 1}
data-direction='next'
onClick={this.handleSlideChange}
className='next'
>
Next
</button>
</div>
</div>
<div className='product__name'>{item.name} {item.currentImageIndex}</div>
<div className='product__price'>{item.price}</div>
</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>

Problem updating parent state from child component in React

I have a class component(actually the collection of the same components) where I have 2 buttons + and - to increase and decrease quantity of watches. Min amount of watches is 1 and max amount is 10. I have regulated this with this 2 functions increaseAmountHandler and decreaseAmountHandler. With this two buttons it's all ok. But the problem is that I have to sum up the value of calculated watches in parent component and I cannot forward the summed up values of the watches to a parent component to state variable totalAmount. Cannot use Redux becacuse it's a collection of watches component and each have own + and - button already occupied with this 2 increaseAmountHandler, decreaseAmountHandler functions.
Anyone idea how to solve this?
Child component:
import React, { Component } from 'react';
import Modal from '.././UI/Modal';
class SelectedWatch extends Component {
constructor(props) {
super(props)
this.state = {
watchQuantity: 1,
watchAmount: 1
}
}
increaseAmountHandler = () => {
if(this.state.watchQuantity < 1) {
this.setState({
watchQuantity: 0,
watchAmount: 0
})
return;
} else if (this.state.watchQuantity >= 10){
this.setState({
watchQuantity: 10,
watchAmount: this.props.selectedWatch.selectedWatchPrice * this.state.watchQuantity
})
return;
}
this.setState({
watchQuantity: this.state.watchQuantity + 1,
watchAmount: this.props.selectedWatch.selectedWatchPrice * this.state.watchQuantity
})
}
decreaseAmountHandler = () => {
if(this.state.watchQuantity < 1) {
this.setState({
watchQuantity: 0,
watchAmount: 0
})
return;
} else if (this.state.watchQuantity >= 10){
this.setState({
watchQuantity: 9,
watchAmount: this.props.selectedWatch.selectedWatchPrice * this.state.watchQuantity
})
return;
}
this.setState({
watchQuantity: this.state.watchQuantity - 1,
watchAmount: this.props.selectedWatch.selectedWatchPrice * this.state.watchQuantity
})
}
render() {
return (
<div className={"shopping-cart-product" + (this.state.watchQuantity < 1 ? ' notDisplayed' : '')}>
<div className="product-info">
<div>
<h3>{this.props.selectedWatch.selectedWatchName}</h3>
<p>${this.props.selectedWatch.selectedWatchPrice} × {this.state.watchQuantity}</p>
</div>
<img src={this.props.selectedWatch.selectedWatchUrl} />
</div>
<div className="product-count">
<button onClick={this.decreaseAmountHandler}>-</button>
<span>{this.state.watchQuantity}</span>
<button onClick={this.increaseAmountHandler}>+</button>
</div>
</div>
);
}
}
export default SelectedWatch;
Parent component:
import React, { Component } from 'react';
import EnteredWatch from '.././components/EnteredWatch/EnteredWatch';
import SelectedWatch from '.././components/SelectedWatch/SelectedWatch';
class App extends Component {
constructor(props) {
super(props)
this.state = {
watchName: '',
watchDescription: '',
watchUrl: '',
watchPrice: '',
watchId: '',
watchAmount: '',
watchQuantity: 1,
enteredWatchList: [],
selectedWatchName: '',
selectedWatchDescription: '',
selectedWatchUrl: '',
selectedWatchPrice: '',
selectedWatchId: '',
selectedWatchAmount: '',
selectedWatchQuantity: 1,
selectedWatchList: [],
totalAmount: 0,
}
}
submitHandler = (event) => {
event.preventDefault();
let watchId = Math.floor((Math.random() * 100) + 1);
let watchName = this.state.watchName;
let watchDescription = this.state.watchDescription;
let watchUrl = this.state.watchUrl;
let watchPrice = this.state.watchPrice;
let watchQuantity = this.state.watchQuantity;
this.setState({
enteredWatchList: this.state.enteredWatchList.concat({watchName, watchUrl, watchDescription, watchPrice, watchId, watchQuantity})
})
add = (selectedWatchName, selectedWatchUrl, selectedWatchDescription, selectedWatchPrice, index, selectedWatchQuantity) => {
let arr = this.state.selectedWatchList;
let found = arr.some(el => {
return el.selectedWatchName === selectedWatchName;
});
if (!found) {
return arr.concat({selectedWatchName, selectedWatchUrl, selectedWatchDescription, selectedWatchPrice, index, selectedWatchQuantity});
} else {
return this.state.selectedWatchList;
}
}
buyWatchHandler = (selectedWatchName, selectedWatchUrl, selectedWatchDescription, selectedWatchPrice, index, selectedWatchQuantity) => {
let arr = this.add(selectedWatchName, selectedWatchUrl, selectedWatchDescription, selectedWatchPrice, index, selectedWatchQuantity);
this.setState({
selectedWatchName: selectedWatchName,
selectedWatchUrl: selectedWatchUrl,
selectedWatchDescription: selectedWatchDescription,
selectedWatchPrice: selectedWatchPrice,
selectedWatchId: index,
selectedWatchQuantity: selectedWatchQuantity,
selectedWatchList: arr
});
}
render() {
const enteredWatches = this.state.enteredWatchList.map((enteredWatch, index) => {
return <EnteredWatch
key={index}
enteredWatch={enteredWatch}
selected={this.buyWatchHandler.bind(this, enteredWatch.watchName, enteredWatch.watchUrl,
enteredWatch.watchDescription, enteredWatch.watchPrice, index, enteredWatch.watchQuantity)}
/>
});
const selectedWatches = this.state.selectedWatchList.map((selectedWatch, index) => {
const active = this.state.activeIndex;
return <SelectedWatch
key={index}
active={index === active}
selectedWatch={selectedWatch}
/>
});
return (
<div className="App">
<div className="container-fluid">
<div className="container">
<div className="add-product">
<form>
<div>
<label>Product name:</label>
<input
type="text"
placeholder="Casio Watch"
required
value={this.state.watchName}
onChange={event => this.setState({watchName: event.target.value})}
/>
</div>
<div>
<label>Product description:</label>
<textarea
placeholder="Sample description..."
value={this.state.watchDescription}
onChange={event => this.setState({watchDescription: event.target.value})}
>
</textarea>
</div>
<div>
<label>Product image:</label>
<input
type="text"
placeholder="http://...jpg"
value={this.state.watchUrl}
pattern="https?://.+" required
onChange={event => this.setState({watchUrl: event.target.value})}
/>
</div>
<div>
<label>Product price:</label>
<input
type="number"
min="0"
placeholder="22"
value={this.state.watchPrice}
onChange={event => this.setState({watchPrice: event.target.value})}
/>
</div>
<button
type="submit"
onClick={event => this.submitHandler(event)}
>
Add a new Task
</button>
</form>
</div>
<div className="list-products">
<ul>
{enteredWatches}
</ul>
</div>
<div className="shopping-cart">
<div className="shopping-cart-products">
<ul>
{selectedWatches}
</ul>
</div>
<div className="shopping-cart-summary">
<div>Total: <b>${this.state.totalAmount}</b></div>
<div><button onClick={this.summaryHandler}>Purchase</button></div>
</div>
</div>
</div>
</div>
</div>
);
}
}
export default App;

The parent has to keep track of how many watches have been added.
Make the parent smart (has state), and the children dumb (no state).
Manage all the state in the parent, and put the click handlers in the parent too.
Pass those handlers down to the child, to be fired when its buttons are clicked. Something like this:
class Parent extends React.Component {
this.state = {
cart: [],
watches: [
{ id: 1, name: "Casio", description: "...", price: 25 },
{ id: 2, name: "Rolex", description: "...", price: 3000 },
{ id: 3, name: "Timex", description: "...", price: 10 },
],
}
handleClickIncrement = (watchId) => {
//add it to the cart (or increment it if its already there)
}
handleClickDecrement = (watchId) => {
//remove it from the cart (or deccrement it if its already there)
}
getCartTotal() {
//loop over cart and calculate
}
renderWatches() {
this.state.watches.map(watch => (
<Watch id={watch.id}
name={watch.name}
description={watch.description}
price={watch.price}
onClickIncrement={() => { this.handleClickIncrement(watch.id); }}
onClickDecrement={() => { this.handleClickDecrement(watch.id); }}
))
}
render() {
<div>
<h1>Our selection of watches:</h1>
{this.renderWatches()}
<h1>Your cart total: {this.getCartTotal()}</h1>
</div>
}
}
class Watch extends React.Component {
props = {
id,
name,
description,
price,
quantityInCart,
onClickIncrementButton,
onClickDecrementButton
}
render() {
<div>
<h1>{this.props.name}</h1>
<p>{this.props.description}</p>
<h5>${this.props.price}</h5>
<button onClick={this.props.onClickIncrementButton}>+</button>
<button onClick={this.props.onClickDecrementButton}>-</button>
</div>
}
}

React - set state on unmounted component

I tried a lot of ways to make it works but it didn't. Probably I don't understand the React idea or I missed something. My child via callback try to modify the global/parent state and then I got the well known error.
index.js:1452 Warning: Can't call setState (or forceUpdate) on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and asynchronous tasks in the componentWillUnmount method.
I try to use variable _isMounted so before setState I did:
if (this.isMounted()) {
this.setState({...});
}
Unfortunately it doesn't work.
The problem is when the function this.handleChangeAlgorithms is invoked from the child.
My code
class ConfigurationForm extends Component {
constructor(props) {
super(props);
this.state = {
choosenAlgorithm: null,
htmlType: null,
customHtml: null,
isOpenModal: false,
generatedHTMlConfig: {
headers: 1,
paragraphs: 1,
buttons: 1,
links: 1,
inputs: 1,
images: 1,
},
};
}
handleChangeAlgorithms = event => {
let algorithmName = event.target.value;
let newChoosenAlgorithm = this.props.algorithms.filter(
e => e.value === algorithmName,
)[0];
// this.setState({choosenAlgorithm: newChoosenAlgorithm});
this.props.callbackConfigurationForm(algorithmName);
};
handleChangeHtmlType(event) {
let newHtmlType = event.target.value;
console.log(newHtmlType);
if (newHtmlType === "default") {
this.setState({ isOpenModal: true });
} else {
this.setState({ htmlType: newHtmlType });
}
}
handleUserFile(event) {
let file = event.target.files[0];
this.setState({ customHtml: file });
this.props.callbackConfigurationFormPreview(file);
}
handleSubmit(event) {
event.preventDefault();
let htmlContent = null;
let htmltypeKey = Object.keys(HtmlType).find(
key => HtmlType[key] === HtmlType.default,
);
console.log(htmltypeKey);
// if (this.state.htmlType === 'default'){
// htmlContent = this.loadTemplate();
htmlContent = generateHTML(this.state.generatedHTMlConfig);
console.log(htmlContent);
// } else {
// htmlContent=this.state.customHtml;
// }
let config = {
algorithm: this.state.choosenAlgorithm,
html: htmlContent,
};
console.log(config);
this.props.callbackConfigurationForm(config);
}
loadTemplate() {
let loadedTemplate = null;
let file = "html-templates/example.html";
let request = new XMLHttpRequest();
request.open("GET", file, false);
request.send(null);
if (request.status === 200) {
loadedTemplate = request.responseText;
}
return loadedTemplate;
}
renderHtmlTypesList = () => {
let list = [];
for (const htmlKey of Object.keys(HtmlType)) {
list.push(
<option key={htmlKey} value={htmlKey}>
{HtmlType[htmlKey]}
</option>,
);
}
return list;
};
generateHTMLFromPopup() {
this.setState({ isOpenModal: false });
}
changeHeaders(event, type) {
console.log(type);
console.log(event.target.value);
let prevConfig = { ...this.state.generatedHTMlConfig };
switch (type) {
case "Headers":
prevConfig.headers = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
case "Paragraphs":
prevConfig.paragraphs = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
case "Buttons":
prevConfig.buttons = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
case "Links":
prevConfig.links = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
case "Inputs":
prevConfig.inputs = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
case "Images":
prevConfig.images = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
}
}
render() {
return (
<Row>
{/* todo 12.11.2018 extract to another component! */}
<Modal
open={this.state.isOpenModal}
header="Generate Html"
actions={
<div>
<Button
modal="close"
waves="light"
className="red lighten-2"
>
Cancel
</Button>
<Button
modal="close"
waves="light"
className="blue"
onClick={this.generateHTMLFromPopup.bind(this)}
>
<Icon left>build</Icon>Generate
</Button>
</div>
}
>
<p>Choose HTML elements for generated HTML.</p>
<Input
type="number"
label="Headers"
value={this.state.generatedHTMlConfig.headers}
onChange={e => this.changeHeaders(e, "Headers")}
/>
<Input
type="number"
label="Paragraphs"
value={this.state.generatedHTMlConfig.paragraphs}
onChange={e => this.changeHeaders(e, "Paragraphs")}
/>
<Input
type="number"
label="Buttons"
value={this.state.generatedHTMlConfig.buttons}
onChange={e => this.changeHeaders(e, "Buttons")}
/>
<Input
type="number"
label="Links"
value={this.state.generatedHTMlConfig.links}
onChange={e => this.changeHeaders(e, "Links")}
/>
<Input
type="number"
label="Inputs"
value={this.state.generatedHTMlConfig.inputs}
onChange={e => this.changeHeaders(e, "Inputs")}
/>
<Input
type="number"
label="Images"
value={this.state.generatedHTMlConfig.images}
onChange={e => this.changeHeaders(e, "Images")}
/>
</Modal>
<h2>Algorithm</h2>
<Row>
<Input
s={12}
type="select"
label="Select algorithm"
defaultValue=""
onChange={this.handleChangeAlgorithms}
>
<option value="" disabled>
Choose an algorithm
</option>
{this.props.algorithms.map(item => (
<option key={item.value} value={item.value}>
{item.name}
</option>
))}
</Input>
</Row>
{this.state.choosenAlgorithm ? (
<Collapsible popout>
<CollapsibleItem header="Details" icon="notes">
<ol>
{this.state.choosenAlgorithm.details.steps.map(
(step, index) => (
<li key={index}>{step}</li>
),
)}
</ol>
</CollapsibleItem>
</Collapsible>
) : null}
<h2>HTML to obfuscate</h2>
<Row>
<Input
s={12}
type="select"
label="HTML type"
defaultValue=""
onChange={this.handleChangeHtmlType}
>
<option value="" disabled>
Choose HTML
</option>
{this.renderHtmlTypesList()}
</Input>
</Row>
{this.state.htmlType === "custom" ? (
<Row>
<Input
type="file"
label="File"
onChange={this.handleUserFile}
/>
</Row>
) : null}
<div className="center-align">
<Button type={"button"} onClick={this.handleSubmit}>
Process<Icon left>autorenew</Icon>
</Button>
</div>
</Row>
);
}
}
class App extends Component {
_isMounted = false;
constructor(props) {
super(props);
this.state = {
isMounted: false,
//export to enum
algorithms: [
{
name: "Html to Javascript",
value: "1",
details: {
steps: [
"Split HTML file line by line.",
"Replace white characters.",
"Create function which add lines to document using document.write function.",
],
},
},
{
name: "Html to Unicode characters",
value: "2",
details: {
steps: [
"Create js function encoding characters to Unicode characters.",
"Create decoding function.",
"Add output from decoding function to HTML.",
],
},
},
{
name: "Html to escape characters",
value: "3",
details: {
steps: [
"Change endcoding using escape javascript function.",
"Decode using unescape javascript function.",
"Add element to HTML.",
],
},
},
{
name:
"Using own encoding and decoding function. [NOT IMPLEMENTED YET]",
value: "4",
details: {
steps: [
"Encode HTML using own function.",
"Save encoded content into js variable.",
"Decode using own decoding function.",
"Add element to HTML document.",
],
},
},
{
name: "Combine above methods [NOT IMPLEMENTED YET]",
value: "5",
details: {
steps: ["To be done..."],
},
},
],
previewHtml: null,
obfuscationConfig: null,
activeTab: 1,
};
}
componentDidMount() {
this._isMounted = true;
}
componentWillUnmount() {
this._isMounted = false;
}
processDataFromConfigurationForm = config => {
console.info(config);
if (this._isMounted) {
this.setState({
test: Date.now(),
// obfuscationConfig: config,
// doObfuscation: true,
// activeTab:3,
// previewHtml: config.html
});
}
};
render() {
return (
<div>
<header className="App">
<h1>HTML obfuscator</h1>
</header>
<Tabs>
<Tab
title="Configuration"
active={this.state.activeTab === 1}
>
<ConfigurationForm
algorithms={this.state.algorithms}
config={this.state.obfuscationConfig}
callbackConfigurationForm={
this.processDataFromConfigurationForm
}
/>
</Tab>
<Tab
title="HTML Preview"
active={this.state.activeTab === 2}
disabled={!this.state.previewHtml}
>
<HTMLPreview previewHtml={this.state.previewHtml} />
</Tab>
<Tab
title="Result"
active={this.state.activeTab === 3}
disabled={!this.state.obfuscationConfig}
>
{this.state.obfuscationConfig ? (
<ObfuscationOutput
config={this.state.obfuscationConfig}
/>
) : null}
</Tab>
</Tabs>
</div>
);
}
}
export default App;
The error

Try to add a constructor to your parent class, indeed, you can initialize the component state before the first modification:
class App extends Component {
constructor(props) {
super(props);
this.state = {
test1: Date.now()
};
}
// here you can update the state as you want, for example
foobar(event) {
this.setState({test1: event.target.value });
}
}
Hope it can help you...

Setting the state inside of the lifecycle method componentDidMount() should do the trick.
Oh I didn't see that someone already suggested that, glad you got it working

Handle Input with Same State Value

I'm building a shopping cart application and I ran into a problem where all my inputs have the same state value. Everything works fine but when I type in one input box, it's the same throughout all my other inputs.
I tried adding a name field to the input and setting my initial state to undefined and that works fine but the numbers don't go through.
How do we handle inputs to be different when they have the same state value? Or is this not possible / dumb to do?
class App extends Component {
state = {
items: {
1: {
id: 1, name: 'Yeezys', price: 300, remaining: 5
},
2: {
id: 2, name: 'Github Sweater', price: 50, remaining: 5
},
3: {
id: 3, name: 'Protein Powder', price: 30, remaining: 5
}
},
itemQuantity: 0
},
render() {
return (
<div>
<h1>Shopping Area</h1>
{Object.values(items).map(item => (
<div key={item.id}>
<h2>{item.name}</h2>
<h2>$ {item.price}</h2>
{item.remaining === 0 ? (
<p style={{ 'color': 'red' }}>Sold Out</p>
) : (
<div>
<p>Remaining: {item.remaining}</p>
<input
type="number"
value={ itemQuantity }
onChange={e => this.setState({ itemQuantity: e.target.value})}
placeholder="quantity"
min={1}
max={5}
/>
<button onClick={() => this.addItem(item)}>Add To Cart</button>
</div>
)}
</div>
))}
</div>
)
}
}

If you are using same state key for all input, All input take value from one place and update to one place. To avoid this you have to use separate state. I suppose you are trying to show input for a list of item.
To achive you can create a component for list item and keep state in list item component. As each component have their own state, state value will not conflict.
Here is an example
class CardItem extends Component {
state = {
number: 0
}
render() {
render (
<input type="text" value={this.state.number} onChange={e => this.setState({ number: e.target.value })} />
)
}
}
class Main extends Component {
render () {
const list = [0,1,2,3,4]
return (
list.map(item => <CardItem data={item} />)
)
}
}

This is a solution which the problem is loosely interpreted, but it does work without having to create another component. As you know, you needed to separate the state of each items in the cart. I did this by dynamically initializing and setting the quantity states of each item. You can see the state changes with this example:
class App extends React.Component {
constructor(props) {
super(props);
this.state = { quantities: {} }
}
componentDidMount() {
let itemIDs = ['1', '2', '3', 'XX']; //use your own list of items
itemIDs.forEach(id => {
this.setState({quantities: Object.assign(this.state.quantities, {[id]: 0})});
})
}
render() {
let list = Object.keys(this.state.quantities).map(id => {
return (
<div>
<label for={id}>Item {id}</label>
<input
id={id}
key={id}
type="number"
value={this.state.quantities[id]}
onChange={e => {
this.setState({quantities: Object.assign(this.state.quantities, {[id]: e.target.value})})
}}
/>
</div>
);
})
return (
<div>
{list}
<div>STATE: {JSON.stringify(this.state)}</div>
</div>
);
}
}
ReactDOM.render(<App/>, document.getElementById('root'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id='root'></div>
You can modify the state structure to your liking.

Here is how I usually handle this scenario. You say that you get an array of items? Each item object should contain a key to store the value (count in my example). You can use a generic onChange handler to update an individual item in the array. So now, your state is managing the list of items instead of each individual input value. This makes your component much more flexible and it will be able to handle any amount of items with no code changes:
const itemData = [
{ id: 0, count: 0, label: 'Number 1' },
{ id: 1, count: 0, label: 'Number 2' },
{ id: 2, count: 0, label: 'Number 3' },
{ id: 3, count: 0, label: 'Number 4' }
];
class App extends React.Component {
state = {
items: itemData
}
handleCountChange = (itemId, e) => {
// Get value from input
const count = e.target.value;
this.setState( prevState => ({
items: prevState.items.map( item => {
// Find matching item by id
if(item.id === itemId) {
// Update item count based on input value
item.count = count;
}
return item;
})
}))
};
renderItems = () => {
// Map through all items and render inputs
return this.state.items.map( item => (
<label key={item.label}>
{item.label}:
<input
type="number"
value={item.count}
onChange={this.handleCountChange.bind(this, item.id)}
/>
</label>
));
};
render() {
return (
<div>
{this.renderItems()}
</div>
)
}
}
ReactDOM.render(<App />, document.getElementById('root'));
label {
display: block;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="root"></div>

You can't use the same state for the both inputs. Try to use a different state for each one like that:
class App extends Component {
state = {
number: ""
}
render() {
return (
<div>
<input
type="number"
value={this.state.number}
onChange={e => this.setState({ number: e.target.value })}
/>
<input
type="number"
value={this.state.number2}
onChange={e => this.setState({ number2: e.target.value })}
/>
</div>
)
}
}

React 16 counter value inside setState methods gets propagated in next list items

I have achieved to increase the list items count values and cost assigned to them using reduce, setState methods e.g Tea x 2 (clicked n times, here 2) then cost will become 15 x 2 = 30; depends on the number of clicks. This is working.
When I click on first items e.g Tea x 1 = 15 then the second item twice coffee x 2.
What actually happens is the counter and cost gets added to coffee item and both items display counter as Tea x 2 also coffee x 2.
Where expected is Tea x 1 and coffee x 2 as clicked twice. So here setState or counter do not handle with multiple click values.
What am I missing here?
import React from "react";
import { Container, Row, Col } from "reactstrap";
const MorningDrinks = [
{
id: "1",
name: "Tea",
cost: 15
},
{
id: "2",
name: "Coffee",
cost: 15
},
{
id: "3",
name: "Milk",
cost: 15
}
];
const ChoclateDrinks = [
{
id: "4",
name: "Smothe",
cost: 15
},
{
id: "5",
name: "hot Chocolate",
cost: 15
}
];
class MenuCard extends React.Component {
state = {
selectedItems: [],
counter: 1
};
selectItem = item => {
if (this.state.selectedItems.includes(item)) {
this.setState(prevState => ({
selectedItems: prevState.selectedItems,
counter: ++this.state.counter
}));
} else {
this.setState(prevState => ({
selectedItems: prevState.selectedItems.concat(item)
}));
}
};
render() {
return (
<Container>
<p>
Welcome {this.props.name} !Pick your any Break-fast menu you want{" "}
</p>
<Row>
<Col xs="3">
<ul>
<h2>Morning Drinks </h2>
{MorningDrinks.map((item, i) => (
<li
style={{ cursor: "pointer" }}
key={i}
onClick={() => this.selectItem(item)}
>
{" "}
{item.name} {item.cost}{" "}
</li>
))}
</ul>
<ul>
<h2>Chocolate Drinks </h2>
{ChoclateDrinks.map((item, i) => (
<li
style={{ cursor: "pointer" }}
key={i}
onClick={() => this.selectItem(item)}
>
{item.name}
{item.cost}
</li>
))}
</ul>
</Col>
<Col xs="3">
<ul>
<h2>Your orders </h2>
{this.state.selectedItems.map((item, i) => (
<li key={i}>
{item.name}
{item.cost}
{this.state.counter}
</li>
))}
</ul>
</Col>
<Col xs="3">
<ul>
<h3>Total</h3>
{this.state.selectedItems.reduce(
(acc, item) => acc + item.cost * this.state.counter,
0
)}
</ul>
</Col>
</Row>
</Container>
);
}
}
export default MenuCard;

Maintaining your implementation I made few changes to your existing code. See below:
import React from 'react';
import { Container, Row, Col } from "reactstrap";
const MorningDrinks = [
{
id: "1",
name: "Tea",
cost: 15
},
{
id: "2",
name: "Coffee",
cost: 15
},
{
id: "3",
name: "Milk",
cost: 15
}
];
const ChoclateDrinks = [
{
id: "4",
name: "Smoothie",
cost: 15
},
{
id: "5",
name: "Hot Chocolate",
cost: 15
}
];
class MenuCard extends React.Component {
state = {
selectedItems: []
};
selectItem = item => {
const { counter, selectedItems } = this.state;
const newItem = {
...item,
quantity: 1
};
// check if item already exist
const el = selectedItems.filter(el => el.id === newItem.id);
if (selectedItems.length === 0) {
this.setState({
selectedItems: [...selectedItems, newItem]
});
} else {
if (el.length) {
const newSelectedItems = selectedItems.map((item) => {
if (item.id === newItem.id) {
item.quantity++;
}
return item;
});
this.setState({
selectedItems: newSelectedItems
});
} else {
this.setState({
selectedItems: [...selectedItems, newItem]
});
}
}
};
render() {
const { counter, selectedItems } = this.state;
return (
<Container>
<p>
Welcome {this.props.name}! Pick your any Break-fast menu you want{" "}
</p>
<Row>
<Col xs="3">
<ul>
<h2>Morning Drinks </h2>
{MorningDrinks.map((item, i) => (
<li
style={{ cursor: "pointer" }}
key={i}
onClick={() => this.selectItem(item)}
>
{" "}
{item.name} {item.cost}{" "}
</li>
))}
</ul>
<ul>
<h2>Chocolate Drinks </h2>
{ChoclateDrinks.map((item, i) => (
<li
style={{ cursor: "pointer" }}
key={i}
onClick={() => this.selectItem(item)}
>
{item.name} {item.cost}
</li>
))}
</ul>
</Col>
<Col xs="3">
<ul>
<h2>Your orders </h2>
{selectedItems.map((item, i) => (
<li key={i}>
{item.name} {item.cost} {item.quantity}
</li>
))}
</ul>
</Col>
<Col xs="3">
<ul>
<h3>Total</h3>
{selectedItems.reduce(
(acc, item) => acc + item.cost * item.quantity,
0
)}
</ul>
</Col>
</Row>
</Container>
);
}
}
export default MenuCard;

Under your current implementation: counter is a blanket variable that increments once per click anywhere in your menu.
Hence, counter only knows total clicks, not individual clicks.
I assume you want to count clicks per item.
The easiest way to do this would be within your record of each item that has been clicked.
Your problem is a lot easier to solve if you manage your cart (selectedItems) in object form, wherein each object carries an individual quantity property.
See below for a practical example.
// Drinks.
const drinks = [
{
id: "1",
name: "tea",
cost: 15
},
{
id: "2",
name: "coffee",
cost: 15
},
{
id: "3",
name: "milk",
cost: 15
},
{
id: "4",
name: "smoothie",
cost: 15
},
{
id: "5",
name: "hot chocolate",
cost: 15
}
]
// Menu.
class Menu extends React.Component {
// Constructor.
constructor(props) {
super(props) // Super Props.
this.state = {cart: {}} // Initial State.
}
// Render.
render() {
// Variables.
const { state } = this // State.
const { cart } = state // Drinks.
return (
<div>
{/* Drinks. */}
<ul>
<h2>Drinks</h2>
{drinks.map((drink, index) => (
<li style={{ cursor: "pointer" }} key={drink.id} onClick={() => this.addToCart(drink)}>
{drink.name} ${(drink.cost).toFixed(2)}
</li>
))}
</ul>
{/* Cart. */}
<ul>
<h2>Cart</h2>
{Object.keys(cart).map((key, index) => (
<li key={key}>
${(cart[key].cost).toFixed(2)}
{cart[key].name}
{cart[key].quantity}
</li>
))}
</ul>
{/* Total. */}
<ul>
<h3>Total</h3>
${Object.keys(cart).reduce((total, key) => total + (cart[key].cost * cart[key].quantity), 0).toFixed(2)}
</ul>
</div>
)
}
// Add To Cart.
addToCart = (item) => {
// Variables.
const { state } = this // State.
const { cart } = state // Selected Items.
const { id } = item
// Is In Cart?
const isInCart = cart[id] // Is In Cart.
if (isInCart) return this.setState({cart: {...cart, [id]: {...cart[id], quantity: cart[id].quantity + 1}}}) // Update Cart.
// Does Not Exist.
return this.setState({cart: {...cart, [id]: {...item, quantity: 1}}}) // Add To Cart.
}
}
// ReactDOM.render.
ReactDOM.render(<Menu/>, document.querySelector('#root'))
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="root"></div>

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