Develop Reference

Why Is the button returning null values for my event.target in my button?

When I'm clicking the button, I am getting that all the values are undefined for the "name" and the "value". I am not sure why, my binding seems correct.
I've tried changing the bindings, I've tried calling an anonymous function for the onClick and passing in the item within my map function. No luck.
import React, { Component } from 'react'
const starterItems = [{ id: 1, name: 'longsword', enhancement: 4 },
{ id: 2, name: 'gauntlet', enhancement: 9 },
{ id: 3, name: 'wizard\'s staff', enhancement: 14 }];
export default class Items extends Component {
constructor(props) {
super(props)
this.handleScoreChange = this.handleScoreChange.bind(this);
this.state = {
items: starterItems
}
}
handleScoreChange(e){
let { name, value } = e.target;
const id = name;
const newScore = value++;
const items = this.state.items.slice();
items.forEach((item) => {
if (item[id] === name){
item.enhancement = newScore
}
});
this.setState(items);
};
render() {
return (
<div>
<h3 data-testid="title">Items</h3>
{this.state.items.map(item => (
<div key={item.id}>
<div name={item.name}data-testid="item">{item.name}</div>
<div name={item.enhancement}data-testid="enhancement" value=
{item.enhancement}>{item.enhancement}
</div>
<button onClick={this.handleScoreChange}>Enhance</button>
</div>
))}
</div>
);
};
}
I am expecting the value of the item passed through to +1

e.target is the DOM reference for the button
including name and value as attributes for the div are not necessary
If you want to get the values for the current name and enhancement when clicking you can add a binding
{
this.state.items.map(item => {
const onClick = this.handleScoreChange.bind(this, item.name, item.enhancement)
return (
<div key={item.id}>
<div name={item.name}data-testid="item">{item.name}</div>
<div name={item.enhancement}data-testid="enhancement" value={item.enhancement}>{item.enhancement}</div>
<button onClick={onClick}>Enhance</button>
</div>
)
)
}
...
handleScoreChange(name, enhancement) {
// your logic here
}

<button onClick={()=>this.handleScoreChange(...item)}>Enhance</button>
please try this i am sure this will work for you
thanks

This Solution Worked. Slight modification from what Omar mentioned. Thank you
import React, { Component } from 'react'
const starterItems = [{ id: 1, name: 'longsword', enhancement: 4 },
{ id: 2, name: 'gauntlet', enhancement: 9 },
{ id: 3, name: 'wizard\'s staff', enhancement: 14 }];
export default class Items extends Component {
constructor(props) {
super(props)
this.state = {
items: starterItems
}
}
enhanceItem(passedItem) {
const newScore = passedItem.enhancement + 1;
const items = this.state.items.slice(); /* creates a copy of state that we can change */
items.forEach((item) => {
if (item.id === passedItem.id) {
return item.enhancement = newScore
}
});
this.setState(items);
};
render() {
return (
<div>
<h3 data-testid="title">Items</h3>
{
this.state.items.map(item => {
const onClick = this.enhanceItem.bind(this, item)
/* this line above binds the item with the onClick Function */
/* notice below, I had to put a return since I added the above code */
return (
<div key={item.id}>
<div data-testid="item">{item.name}</div>
<div data-testid="enhancement">{item.enhancement}</div>
{/* We can use the "data=testid" as a way to grab an item, since it won't impact the html any */}
<button onClick={onClick}>Enhance</button>
</div>
)
})};
</div>
);
};
}

Don't know how to handle input in my project

I'm working under the to-do list project and have got a problem with adding a comment to my list item. This is what I have right now:
App flow
After adding a list item you should be able to click in this item and a new window with comments will appear. In the comments section, comments should be added with Ctrl+Enter combination.
I've got a problem with adding comments to the list item (they should be added to the "comments" array of a particular list item).
Could you please explain what I'm doing wrong and why my comments aren't adding.
UPDATE: I've updated my code but the following mistake appears when I press Ctr+Enter to add a comment: [Error] (http://joxi.ru/Q2KR1G3U4lZJYm)
I've tried to bind the addItem method but no result. What's wrong with the addItem method?
Here is my main component:
App.js
import React, { Component } from 'react';
import './App.css';
import ListInput from './components/listInput'
import ListItem from './components/listItem'
import SideBar from './components/sideBar'
import CommentsSection from './components/commentsSection'
class App extends Component {
constructor(props){
super(props);
this.state = {
items: [
{
id: 0,
text: 'First item',
commentsCount: 0,
comments: [],
displayComment: false
},
{
id: 1,
text: 'Second item',
commentsCount: 0,
comments: [],
displayComment: false
},
{
id: 2,
text: 'Third item',
commentsCount: 0,
comments: [
'Very first comment',
'Second comment',
],
displayComment: false
},
],
nextId: 3,
activeComment: [],
}
}
// Add new item to the list
addItem = inputText => {
let itemsCopy = this.state.items.slice();
itemsCopy.push({id: this.state.nextId, text: inputText});
this.setState({
items: itemsCopy,
nextId: this.state.nextId + 1
})
}
// Remove the item from the list: check if the clicked button id is match
removeItem = id =>
this.setState({
items: this.state.items.filter((item, index) => item.id !== id)
})
setActiveComment = (id) => this.setState({ activeComment: this.state.items[id] });
addComment = (inputComment, activeCommentId ) => {
// find item with id passed and select its comments array
let commentCopy = this.state.items.find(item => item.id === activeCommentId)['comments']
commentCopy.push({comments: inputComment})
this.setState({
comments: commentCopy
})
}
render() {
return (
<div className='App'>
<SideBar />
<div className='flex-container'>
<div className='list-wrapper'>
<h1>Items</h1>
<ListInput inputText='' addItem={this.addItem}/>
<ul>
{
this.state.items.map((item) => {
return <ListItem item={item} key={item.id} id={item.id} removeItem={this.removeItem} setActiveComment={() => this.setActiveComment(item.id)}/>
})
}
</ul>
</div>
<CommentsSection inputComment='' items={this.state.activeComment}/>
</div>
</div>
);
}
}
export default App;
and my Comments Section component:
commentsSection.js
import React from 'react';
import './commentsSection.css';
import CommentInput from './commentInput'
import CommentsItem from './commentsItem'
export default class CommentsSection extends React.Component {
constructor(props){
super(props);
this.state = {value: this.props.inputComment};
this.handleChange = this.handleChange.bind(this);
this.handleEnter = this.handleEnter.bind(this);
this.addComment = this.addComment.bind(this)
}
handleChange = event => this.setState({value: event.target.value})
handleEnter(event) {
if (event.charCode === 13 && event.ctrlKey) {
this.addComment(this.state.value)
}
}
addComment(comment) {
// Ensure the todo text isn't empty
if (comment.length > 0) {
this.props.addComment(comment, this.props.activeComment);
this.setState({value: ''});
}
}
render() {
return (
<div className='component-section'>
<h1>{this.props.items.text}</h1>
<ul>
{ this.props.items.comments &&
this.props.items.comments.map((comment, index) => <p key={index}>{comment}</p>)
}
</ul>
<CommentsItem />
{/*<CommentInput />*/}
<div className='comment-input'>
<input type='text' value={this.state.value} onChange={this.handleChange} onKeyPress={this.handleEnter}/>
</div>
</div>
)
}
}

Change your CommentSection component addComment method and handleEnter method
addComment(comment) {
// Ensure the todo text isn't empty
if (comment.length > 0) {
// pass another argument to this.props.addComment
// looking at your code pass "this.props.items"
this.props.addComment(comment, this.props.items.id);
this.setState({value: ''});
}
}
handleEnter(event) {
if (event.charCode === 13 && event.ctrlKey) {
// passing component state value property as new comment
this.addComment(this.state.value)
}
}
Change your App Component addComment method
addComment = (inputComment, activeCommentId )=> {
// find item with id passed and select its comments array
let commentCopy = this.state.items.find(item => item.id === activeCommentId)['comments']
// if you want to push comments as object
// but looking at your code this is not you want
// commentCopy.push({comments: inputComment})
// if you want to push comments as string
commentCopy.push( inputComment)
this.setState({
comments: commentCopy
})
}

React: adding className to single element of mapped array

I have a child component that maps images from an items array. Upon clicking any item, I am calling addFavorite, which is passed in from the parent.
I am trying to find a way to also have a className added to only the specific image(s) I click on. Any approach I've tried adds the class to all the mapped out elements upon onClick.
var classNames = require('classnames');
class Results extends Component {
render() {
let items = this.props.items
var resultClass = classNames({
'result': true,
});
return (
<div className="resultst" key="results">
{items.map(item =>
<div className = {resultClass}
key={item.id}
onClick= {() => {
this.props.addFavorite(item)
}
}>
<img alt= "" src={item.images.downsized.url} />
</div>
)}
</div>
);
}
}

You could create a separate favorites array in your parent component that you store all the favorite items in, and send that to your child component and see if the item is included in the favorites array:
Example
class App extends Component {
state = {
items: [{ id: 1, text: "item 1" }, { id: 2, text: "item 2" }],
favorites: []
};
addFavorite = item => {
const { items, favorites } = this.state;
const copyFavorites = [...favorites];
if (!favorites.some(favorite => favorite.id === item.id)) {
copyFavorites.push(item);
this.setState({ favorites: copyFavorites });
}
};
render() {
const { items, favorites } = this.state;
const { addFavorite } = this;
return (
<div>
<Results
items={items}
favorites={favorites}
addFavorite={addFavorite}
/>
</div>
);
}
}
class Results extends Component {
render() {
const { items, favorites, addFavorite } = this.props;
return (
<div>
{items.map(item => (
<div
key={item.id}
onClick={() => {
addFavorite(item);
}}
>
{favorites.includes(item) && 'Favorite: '}
{item.text}
</div>
))}
</div>
);
}
}

How to toggle css class of a single element in a .map() function in React

I have a .map() function where I'm iterating over an array and rendering elements, like so:
{options.map((option, i) => (
<TachyonsSimpleSelectOption
options={options[i]}
key={i}
onClick={() => this.isSelected(i)}
selected={this.toggleStyles("item")}
/>
I am toggling the state of a selected element like so:
isSelected (i) {
this.setState({ selected: !this.state.selected }, () => { console.log(this.state.selected) })
}
Using a switch statement to change the styles:
toggleStyles(el) {
switch (el) {
case "item":
return this.state.selected ? "bg-light-gray" : "";
break;
}
}
And then passing it in my toggleStyles method as props to the className of the TachyonsSimpleSelectOption Component.
Problem
The class is being toggled for all items in the array, but I only want to target the currently clicked item.
Link to Sandbox.
What am I doing wrong here?

You're using the selected state incorrectly.
In your code, to determine whether it is selected or not, you depends on that state, but you didn't specify which items that is currently selected.
Instead saving a boolean state, you can store which index is currently selected so that only specified item is affected.
This may be a rough answer, but I hope I can give you some ideas.
on your render:
{options.map((option, i) => (
<TachyonsSimpleSelectOption
options={options[i]}
key={i}
onClick={() => this.setState({ selectedItem: i })}
selected={this.determineItemStyle(i)}
/>
))}
on the function that will determine the selected props value:
determineItemStyle(i) {
const isItemSelected = this.state.selectedItem === i;
return isItemSelected ? "bg-light-gray" : "";
}
Hope this answer will give you some eureka moment

You are not telling react which element is toggled. Since the state has just a boolean value selected, it doesn't know which element is selected.
In order to do that, change your isSelected function to :
isSelected (i) {
this.setState({ selected: i }, () => {
console.log(this.state.selected) })
}
Now, the React state knows that the item on index i is selected. Use that to toggle your class now.
In case you want to store multiple selected items, you need to store an array of indices instead of just one index

TachyonsSimpleSelectOption.js:
import React from 'react';
class Option extends React.Component {
render() {
const { selected, name } = this.props;
return(
<h1
onClick={() => this.props.onClick()}
style={{backgroundColor: selected ? 'grey' : 'white'}}
>Hello {name}!</h1>
)
}
}
export default Option;
index.js:
import React from "react";
import { render } from "react-dom";
import TachyonsSimpleSelectOption from "./TachyonsSimpleSelectOption";
const options = ["apple", "pear", "orange"];
const styles = {
selected: "bg-light-gray"
};
class Select extends React.Component {
constructor(props) {
super(props);
this.state = {
open: false,
selected: []
};
this.handleClick = this.handleClick.bind(this);
this.handleBlur = this.handleBlur.bind(this);
this.isSelected = this.isSelected.bind(this);
}
handleBlur() {
this.toggleMenu(close);
}
handleClick(e) {
this.toggleMenu();
}
toggleMenu(close) {
this.setState(
{
open: !this.state.open
},
() => {
this.toggleStyles("menu");
}
);
}
toggleStyles(el, index) {
switch (el) {
case "menu":
return this.state.open ? "db" : "dn";
break;
case "item":
const { selected } = this.state;
return selected.indexOf(index) !== -1;
break;
}
}
isSelected(i) {
let { selected } = this.state;
if (selected.indexOf(i) === -1) {
selected.push(i);
} else {
selected = selected.filter(index => index !== i);
}
this.setState({ selected});
}
render() {
const { options } = this.props;
return (
<div
className="flex flex-column ba"
onBlur={this.handleBlur}
tabIndex={0}
>
<div className="flex-row pa3" onClick={this.handleClick}>
<span className="flex-grow-1 w-50 dib">Title</span>
<span className="flex-grow-1 w-50 dib tr">^</span>
</div>
<div className={this.toggleStyles("menu")}>
{options.map((option, i) => (
<TachyonsSimpleSelectOption
name={options[i]}
key={i}
onClick={() => this.isSelected(i)}
selected={this.toggleStyles("item", i)}
/>
))}
</div>
</div>
);
}
}
render(<Select options={options} />, document.getElementById("root"));
And Link to Sandbox.

React Modal Does Not Close In Between Loading Content

I'm using this react modal plugin: https://github.com/reactjs/react-modal
and I need to show an array of objects in the modal on page load. When the first item shows user clicks a button so isOpen prop is set to false for Modal. Each item has a prop showModal that feeds the value to isOpen for the Modal. As the user keeps clicking I keep setting the value on the current object to false and then set it true for the next object.
This is all working fine but the problem is that the overlay and dialog window stays on screen and only content within the modal is updated. I would like the modal to fully close and open to show content of the next object in array. I had to strip out my code to a simplified version below:
class ProductsModal extends React.Component {
constructor(props) {
super(props);
this.remindMeHandler = this.remindMeHandler.bind(this);
this.state = {
products: [],
modalId: 0
};
}
showModals() {
let products = this.state.products;
//A different function saves the array of product objects in the state so
//I can show them one by one
let currentProduct = products[this.state.popUpId];
if (products.length > 0) {
return <ProductItemModal
product={currentProduct}
showNextPopUp={() => this.showNextPopUp(currentProduct.productId)}
showPopUp={currentProduct['showModal']}
/>;
//showModal is a boolean for each product that sets the value of isOpen
}
}
showNextPopUp() {
//All this does is sets the "showModal" property to false for current
//product and sets it to true for next product so it shows in the Modal
}
render() {
return(
<div>
{this.showModals()}
</div>
);
}
}
class ProductItemModal extends React.Component {
constructor(props) {
super(props);
}
render() {
return(
<Modal
isOpen={this.props.showModal}
contentLabel="Product"
id={this.props.product.productId}
>
<div>
Product Data......
</div>
</Modal>
);
}
}

Had a workaround for all your problems and created this codepen link. It would be like this,
class ProductItemModal extends React.Component {
render() {
const { showModal, product, showNextModal, onClose } = this.props;
return(
<ReactModal
isOpen={showModal}
contentLabel="Product"
onRequestClose={() => onClose()}
>
<p>
<b>Product Id</b> - {product.id}, <b>Product Name</b> - {product.name}
</p>
<button onClick={() => showNextModal()}>Next</button>
</ReactModal>
);
}
}
class ProductsModal extends React.Component {
constructor() {
super();
this.state = {
products: [
{id: 1, name: "Mac", showModal: true},
{id: 2, name: "iPhone", showModal: false},
{id: 3, name: "iPod", showModal: false},
],
modalId: 0
};
}
handleProductItemModalClose(product) {
//backdrop click or escape click handling here
console.log(`Modal closing from Product - ${product.name}`);
}
showModals() {
const { products, modalId } = this.state;
//A different function saves the array of product objects in the state so
//I can show them one by one
let currentProduct = products[modalId];
if(currentProduct) {
return <ProductItemModal
product={currentProduct}
showNextModal={() => this.showNextModal(currentProduct.id)}
showModal={currentProduct["showModal"]}
onClose={() => this.handleProductItemModalClose(currentProduct)}
/>;
//showModal is a boolean for each product that sets the value of isOpen
}
}
showNextModal(currentProductId) {
const { products, modalId } = this.state;
var isLastModal = false;
if(modalId === products.length - 1) {
isLastModal = true;
}
var clonedProducts = [...products];
var currentIndex = clonedProducts.findIndex(product => product.id === currentProductId);
var newIndex = currentIndex + 1;
clonedProducts[currentIndex].showModal = false;
if(!isLastModal) {
clonedProducts[newIndex].showModal = true;
} else {
//comment the following lines if you don't wanna show modal again from the start
newIndex = 0;
clonedProducts[0].showModal = true;
}
//All this does is sets the "showModal" property to false for current
//product and sets it to true for next product so it shows in the Modal
this.setState({
products: clonedProducts
}, () => {
this.setState({
modalId: newIndex
});
});
}
render() {
return(
<div>
{this.showModals()}
</div>
);
}
}
ReactDOM.render(<ProductsModal />, document.getElementById("main"));
Let me know if it helps.
Updated codepen: https://codepen.io/anon/pen/rzVQrw?editors=0110

You need to call setState() of ProductItemModal to close Model. Otherwise, though isOpen is changed, the UI is not re-rendered.

As you probably know that react maintain a virtual DOM and on every time state or props change it compares the difference between browser's DOM(actual dom) and virtual DOM(the one that React maintain) and in your code every time you change the isOpen property all you are doing is only changing the props of the Model component that's why React only update the internal content of the actual Model
to completely close and re-open the model you need to do a small change in your code
instead of returning only one model component in your ProductsModal you need to do something like this so that react know that this modal has been close and otherone has been open Key property is important for performance reason read more
class ProductsModal extends React.Component {
.
.
.
showModals() {
let products = this.state.products;
//A different function saves the array of product objects in the state so
if (products.length > 0) {
return (
//return list of all modal component
products.map((product) =>
<ProductItemModal
product={product}
showNextPopUp={() => this.showNextPopUp(product.productId)}
showPopUp={product['showModal']}
key={product.productId}
/>
)
);
//showModal is a boolean for each product that sets the value of isOpen
}
}
.
.
.
}
all you are doing here is just returning multiple modal and when one model gets the isOpen props as false is close and the other witch gets true is open and now react know that there are two different modals because of key props

Another work around is to use setTimeout. Implementation is as follows-
class ProductItemModal extends React.Component {
render() {
const { showModal, product, selectNextProductFunc, onClose } = this.props;
return(
<ReactModal
isOpen={showModal}
contentLabel="Product"
onRequestClose={() => onClose()}
>
<p>
<b>Product Id</b> - {product.id}, <b>Product Name</b> - {product.name}
</p>
<button onClick={() => selectNextProductFunc(product)}>Next</button>
</ReactModal>
);
}
}
class ProductsModal extends React.Component {
constructor() {
super();
this.state = {
products: [
{id: 1, name: "Mac"},
{id: 2, name: "iPhone"},
{id: 3, name: "iPod"},
],
productId: null,
showModal: true,
};
}
handleProductItemModalClose(product) {
//backdrop click or escape click handling here
console.log(`Modal closing from Product - ${product.name}`);
}
showModals() {
const { products, productId, showModal} = this.state;
//A different function saves the array of product objects in the state so
//I can show them one by one
const getProduct = function(){
if(productId){
return products.find((i) => i.id === productId);
}else{
return products[0]; // first element
}
}
return <ProductItemModal
product={getProduct()}
selectNextProductFunc={this.selectNextProductFunc.bind(this)}
showModal={showModal}
onClose={() => this.handleProductItemModalClose()}
/>;
//showModal is a boolean for each product that sets the value of isOpen
}
selectNextProductFunc(currentProduct) {
const { products} = this.state;
this.setState({
showModal: false
});
const currentProductIndex = products.findIndex((i) => i.id === currentProduct.id);
const modifiedIndex = 0;
if(products[currentProductIndex + 1]){
this.setState({
productId : products[currentProductIndex + 1].id,
});
}else{
this.setState({
productId : modifiedIndex,
});
}
setTimeout(() => {
this.setState({
showModal: true
})
}, 1000);
}
render() {
return(
<div>
{this.showModals()}
</div>
);
}
}
ReactDOM.render(<ProductsModal />, document.getElementById("main"));
jsbin