Mapping over arrays in React - javascript

I'm mapping over each object inside the array of objects inside my state's item property. The issue is, I want to be able to attach a button to each returned item that only works with that item, and not the other items too. Here's what I have so far:
class App extends React.Component {
state = {
item: [],
}
componentDidMount() {
this.setState({
item: [
{
name: 'jacob',
hair: 'brown',
sex: 'male',
}, {
name: 'hannah',
hair: 'brown',
sex: 'female',
}
]
})
}
handleChange = (e) => {
console.log(e.target.value)
var x = Object.assign({}, this.state)
}
render() {
return(
<div>
{ this.state.item.length > 0 ?
(
<div className="row mt-5">
<Item item={ this.state.item } handleChange={ this.handleChange } />
</div>
) : null
}
</div>
)
}
}
class Item extends React.Component {
render() {
return(
<div className="col">
{ this.props.item.map(s => (
<div>
<div className="mt-5">{ s.name }</div>
<button onClick={ this.props.handleChange } value={ s.name }>Click</button>
</div>
))}
</div>
)
}
}
So for instance, if the button's fx was to change the name property of the item it was rendered with, I want it to only change that item and no other items should be affected. Whenever I iterate through it attaches the button's fx to every item, so if I click it for one, I'm really clicking it for all of them, and that's exactly what I don't want.
For those curious, I'm setting the state in componentDidMount to simulate calling an API.
Also, the fx that's currently running in the handleChange is just some messing around I was doing trying to figure out values and a solution to manipulating a nested object inside an array.

Try this refactored code on CodeSandBox,
You have to add keys when iterating Components in React, i've added it, also the Item Component could be function Component since it doesn't handle a state.
Updated: below is the code in case it wouldn't be available on codesandbox.
import React from 'react';
import { render } from 'react-dom';
class App extends React.Component {
state = {
items: [],
}
componentDidMount() {
this.setState({
items: [
{
name: 'jacob',
hair: 'brown',
sex: 'male',
}, {
name: 'hannah',
hair: 'brown',
sex: 'female',
}
]
})
}
handleChange = (e) => {
console.log(e.target.value)
}
render() {
const { items } = this.state;
return (
<div>
{items.length && (
items.map((item, index) => (
<div className="row mt-5" key={index}>
<Item item={item} handleChange={this.handleChange} />
</div>
))
)
}
</div>
)
}
}
const Item = ({ item, handleChange }) => (
<div className="col">
<div className="mt-5">{item.name}</div>
<button onClick={handleChange} value={item.name}>Click</button>
</div>
);
render(<App />, document.getElementById('root'));

I think you want to pass the individual element in to your handleChange:
{ this.props.item.map((s, i) => {
<div>
<div className="mt-5">{ s.name }</div>
<button key={i} onClick={ (s) => this.props.handleChange(s) } value={ s.name }>Click</button>
</div>
})}
This way, you will have the individual item passed in as an argument, so when you are writing your handleChange, you can do whatever you want with just that item and not the whole array.

Related

Why onclick function isn't rendering (React.js)?

I’m working on building an e-commerce website in React. In which, there will be a navigation bar with all the categories and once a user clicked on a specific category, it will render all the products that belongs to the checked category in the same page. In the project I have two .js files which are NavBar.js where it contains all the stuff for the navigation bar and AllItems.js where all products are rendered.
My problem now, is that onclick in NavBar.js doesn't render AllItems.js. It works with console.log("sss") but it doesn't work with <AllItems/>
Here is my code in NavBar.js
function NavBar() {
const [allCategories, setAllCategories] = useState([])
const [currency, setCurrency] = useState([])
useEffect(() => {
fetchAnyQuery(
`
query{
categories{
name
}
}
`).then(data => {
setAllCategories( data.data.categories )
})
},[])
// for currency options
useEffect(() => {
fetchAnyQuery(`
query{
currencies
}
`
).then(data => {
setCurrency(data.data.currencies)
})
},[])
return (
<nav id = "NavBar">
<div id="NavBar-content">
<div className = "leftSide" id = "leftNav">
{allCategories.map((allCategories, index) => {
if (index == 0){
// return a checked tab
return(
<>
<input className='radio-category' id={allCategories.name} type='radio' name="nav" onClick={
function (){
console.log("ssss");
<AllItems/>
}
} checked/>
<label htmlFor={allCategories.name} className='category-label'><h5 className="tab-text">{allCategories.name.toUpperCase()}</h5></label>
</>
)
}
else {
// return unchecked tab
return(
<>
<input className='radio-category' id={allCategories.name} type='radio' name="nav" onClick={ function (){changeCategoryState(allCategories.name); <AllItems/>} } />
<label htmlFor={allCategories.name} className='category-label'><h5 className="tab-text">{allCategories.name.toUpperCase()}</h5></label>
</>
)
}
})}
</div>
<div className = "centerSide">
{/*<a href="/">*/}
{/* /!*<img src={logo} />*!/*/}
{/* Logo*/}
{/*</a>*/}
<button onClick={function (){ console.log(getCategoryState()) }}>
Abo Kalb
</button>
</div>
<div className = "rightSide">
<select className="currencySelector" id="currencySelector">
{currency.map((currency, index) =>{
return(
<option value={ JSON.stringify(currency.indexOf(index)) } > {getSymbolFromCurrency(currency.toString()) + " " + currency.toString()} </option>
)
})}
</select>
</div>
</div>
</nav>
);
}
export default NavBar;
Also, here is my code for AllItems.js file:
function AllItems() {
// The state that I want to use in NavBar.js
// const [category, setCategory] = useState([getCategoryState()])
const [products, setProducts] = useState([])
useEffect(() => {
fetchAnyQuery(
`
query{
categories{
name
products{
name
id
}
}
}
`
).then(data => {
// Here I'm trying to do all the required stuff
// console.log(category)
})
},[])
console.log("All Items RENDERED!!")
return (
<>
<h1>{ getCategoryState() }</h1>
<div className="itemContainer" id="itemContainer">
</div>
</>
)
}
export default AllItems;
From what I understood, you want to render different categories' data based on which category is clicked, but you can not call a component on the click, that's not how React works. Instead set a state and render the component conditionally according to the state value, and set the state when the component needs to be rendered.
Assuming that you're fetching your items from a server, you will have to store that data in a state
const [allItems, setAllTems] = useState([])
Then add a state that will help you render your items conditionally
const [showAllItems, setShowAllItems] = useState(false)
In your JSX, use && to render your data when the state gets all the data
<> {showAllItems && <AllItems>} </>
if you're having troubles understanding how this works, I suggest you checking React documentations, it explains very well how you can manipulate the state
Use a parent component to manage the state. When you update the radio input in Nav update the state, and then filter the data based on that selection.
const { useState } = React;
function Example({ data }) {
const [ items, setItems ] = useState(data);
const [ selection, setSelection ] = useState('');
// When you click a button, set the selection state
function handleClick(e) {
setSelection(e.target.dataset.type);
}
// `filter` out the items you want to display
// based on the selection
function filteredItems() {
return items.filter(item => item.type === selection);
}
return (
<div>
<Nav>
Dairy: <input onClick={handleClick} type="radio" data-type="dairy" name="food" />
Meat: <input onClick={handleClick} type="radio" data-type="meat" name="food" />
Vegetable: <input onClick={handleClick} type="radio" data-type="vegetable" name="food" />
</Nav>
<Items items={filteredItems()} />
</div>
);
};
// `map` over the filtered data
function Items({ items }) {
return items.map(item => <div>{item.name}</div>);
}
function Nav({ children }) {
return children;
}
const data = [
{ name: 'cow', type: 'meat' },
{ name: 'bree', type: 'dairy' },
{ name: 'chicken', type: 'meat' },
{ name: 'sprout', type: 'vegetable' }
];
ReactDOM.render(
<Example data={data} />,
document.getElementById('react')
);
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/17.0.2/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/17.0.2/umd/react-dom.production.min.js"></script>
<div id="react"></div>

Toggle one list item instead of entire list

I am making a card that lists radio stations and when you click on a station a picture drops down for that list item. all data i am pulling from a json.
I have tried building the list in the toggle.js and in the app.js files
app.js-- div with toggle (its all inside a card..many divs)
<div class="card-trip-infos">
<div>
<Toggle />
</div>
<img class="card-trip-user avatar-bordered"/>
</div>
toggle.js render block:
state = {
on: false,
}
toggle = () => {
this.setState({
on: !this.state.on
})
}
render() {
return (
<ul>
<div>
<p>{PostData.radios[0].name}</p>
{PostData.radios.map((postDetail, index) => {
return <div>
<li onClick={this.toggle}>
<span id='radioName'>{postDetail.name}</span> <span id='frequency'>{postDetail.frequency}</span>
</li>
{
this.state.on && <img src='imagesrc'></img>
}
</div>
})}
</div>
</ul>
)
}
}
I dont know what exactly is wrong but i expect to be able to toggle a picture for each list row seperately. i am confused where to iterate over my json and where to plug everything in.
many Thanks!!
Since we don't know your toggle function and all your component we can't make exact suggestions but in order to do what you want here (just toggle the selected item), you have two different approaches.
You can keep the selected state in the component itself.
class App extends React.Component {
state = {
cards: [
{ id: 1, name: "foo" },
{ id: 2, name: "bar" },
{ id: 3, name: "baz" }
],
};
render() {
const { cards } = this.state;
return (
<div>
{cards.map(card => (
<Card
key={card.id}
card={card}
/>
))}
</div>
);
}
}
class Card extends React.Component {
state = {
selected: false
};
handleSelect = () =>
this.setState(state => ({
selected: !state.selected
}));
render() {
const { card } = this.props;
return (
<div
className={this.state.selected ? "selected" : ""}
onClick={this.handleSelect}
>
{card.id}-{card.name}
</div>
);
}
}
ReactDOM.render(<App />, document.getElementById("root"));
.selected {
background-color: red;
}
<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" />
You can keep the selected state in the parent component.
class App extends React.Component {
state = {
cards: [
{ id: 1, name: "foo" },
{ id: 2, name: "bar" },
{ id: 3, name: "baz" }
],
selected: {}
};
handleSelect = id =>
this.setState(state => ({
selected: { ...state.selected, [id]: !state.selected[id] }
}));
render() {
const { cards, selected } = this.state;
return (
<div>
{cards.map(card => (
<Card
key={card.id}
card={card}
handleSelect={this.handleSelect}
selected={selected[card.id]}
/>
))}
</div>
);
}
}
const Card = ({ card, handleSelect, selected }) => {
const handleClick = () => handleSelect(card.id);
return (
<div className={selected ? "selected" : ""} onClick={handleClick}>
{card.id}-{card.name}
</div>
);
};
ReactDOM.render(<App />, document.getElementById("root"));
.selected {
background-color: red;
}
<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" />
Create a component for individual list item, have a state there which will hold a boolean property to tell whether the image is to be shown or not. Render function will look something like this:
render (
return (
<li onClick="this.toggleShowImage()">
<div> {props.data.name} </div>
<div> {props.data.frequency} </div>
{this.state.showImage ? <img src='imageUrl' /> : null }
</li>
)
)
Then in toggle.js iterate through your data and create the list components. The render function will look something like below:
render() {
return (
<ul>
{PostData.radios.map((postDetail, index) => {
return <ListItem key={postDetail.name} data={postDetail} />
})}
</ul>
)
}

How to hide all the div while showing the one which is clicked, in React?

I'm generating some identical div through a list. Below is the sample code.
I'm toggling this div
class App extends React.Component {
state = { showKitten: false };
handleToggleKitten = () => {
this.setState((prevState, props) => ({
showKitten: !prevState.showKitten,
}));
};
render() {
return (
<About
data={datalist}
showKitten={this.state.showKitten}
handleToggleKitten={this.handleToggleKitten}
/>
);
}
}
const About = ({ datalist, showKitten, handletogglekitten }) => {
return (
<div>
{datalist.map((item, index) => {
return (
<div key={index}>
<div onClick={handletogglekitten} />
showKitten ? <div /> : null
</div>
);
})}
</div>
);
};
I have defined tooglefunction and the flag state variable in parent and passing them to children and in children component, I'm creating this divs by iterating over a list. Right now I am able to achieve the toggle functionality for the individual div set but I want to hide all the div and show the one which is clicked.
You could use the index value. Here's a working example.
const datalist = ["cat 1", "cat 2", "cat 3"];
class App extends React.Component {
state = { showKittenIndex: null };
render() {
return (
<About
datalist={datalist}
showKittenIndex={this.state.showKittenIndex}
toggleKitten={index => this.setState({ showKittenIndex: index })}
/>
);
}
}
const About = ({ datalist, showKittenIndex, toggleKitten }) => (
<div className="about">
{datalist.map((item, index) => (
<div key={index}>
<button onClick={() => toggleKitten(index)}>toggle {index}</button>
{showKittenIndex === index && <div>{item}</div>}
</div>
))}
</div>
);
I have a very similar approach than #Kunukn.
But I don't see the need to wrap it in a functional component.
import React, { Component } from 'react';
const elements = ['DIV #1', 'DIV #2', 'DIV #3', 'DIV #4', 'DIV #5', 'DIV #6'];
class App extends Component {
constructor(props) {
super(props);
this.state = {
activeElement: null,
allElements: elements,
};
}
render() {
return (
<About
elements={this.state.allElements}
showIndex={this.state.activeElement}
toggleIndex={index => this.setState({ activeElement: index })}
/>
);
}
}
const About = ({ elements, showIndex, toggleIndex }) => (
<div className="about">
{elements.map((element, index) => (
<div key={index}>
<div onClick={() => toggleIndex(index)}>toggleIndex {index}</div>
{showIndex === index && <div>{element}</div>}
</div>
))}
</div>
);
export default App;
I did write a little clickHandler ... I know that it is not needed at the moment, but when you would want to alter the data received with the click-event this could be handled there as well.
EDIT
According to the comment I improved the code a bit by making a functional component showing the DIVs. I did also dismiss the clickHandler() function.

defaultValue is pulling the last value in React

If i click on a particular ToDos edit button, its value should be defaulted inside the textarea but everytime the last ToDo is defaulting, can somebody please help, whether using ref is a right choice or something else, then where i m wrong what i'm suppose to do ?
handleEdit() {
e.preventDefault();
.....
}
renderDisplay() {
return(
<div>
{
this.props.listArr.map((list,i) => {
return(
<div key={i} index={i} ref="newText">
<li>{list}
<div>
<button className="btn btn-primary btn-xs glyphicon glyphicon-pencil"
onClick={this.handleEdit.bind(this)}
/>
</div>
<hr/>
</li>
</div>
)})
}
</div>
);
}
renderForm() {
return(
<div>
<textarea className="form-control" defaultValue={this.refs.newText.innerText} rows="1" cols="100" style={{width: 500}}/>
</div>
)
}
render() {
if(this.state.editing) {
return this.renderForm();
}else {
return this.renderDisplay();
}
}
}
First of all you are using an old ref API. You should use this one, where you set the ref to the instance of the class using this with a callback.
<input ref={ref => {this.myInput = ref}} />
And then you can access its value by just referring to this.myInput .
As for your "bug", keep in mind that you are looping over and overriding the ref. so the last ref assignment would be the last item in the array.
this.props.listArr.map((list,i) => {
return(
<div key={i} index={i} ref="newText">
<li>{list}
There will always be 1 newText ref and it will always be the last item in the array.
You should render different ref names according to the item id and then pass the id of the item to the renderForm so it can access the relevant ref.
With that said, i really recommend to extract the todo to a different component as well as the form. I don't see a valid reason to use refs in this case.
Edit
As a follow-up to your comment, here is a small example of how you would use components instead of refs in order to get information from the child like values etc..
class Todo extends React.Component {
onClick = () => {
const { todoId, onClick } = this.props;
onClick(todoId);
}
render() {
const { value, complete } = this.props;
return (
<div
style={{ textDecoration: complete && 'line-through' }}
onClick={this.onClick}
>
{value}
</div>
);
}
}
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
todos: [
{ id: '1', value: 'to do this', complete: false },
{ id: '2', value: 'todo that', complete: true },
{ id: '3', value: 'will do it later', complete: false }]
}
}
toggleTodo = (todoId) => {
const { todos } = this.state;
const nextState = todos.map(todo => {
if (todo.id !== todoId) return todo;
return {
...todo,
complete: !todo.complete
}
});
this.setState({ todos: nextState });
}
render() {
const { todos } = this.state;
return (
<div >
{
todos.map((todo) => {
return (
<Todo
complete={todo.complete}
key={todo.id}
todoId={todo.id}
value={todo.value}
onClick={this.toggleTodo}
/>
)
})
}
</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>

Editing immutable state items

I'm trying to update some immutable data. However, I am doing it incorrectly and it doesn't work.
My understanding, is I need to pass it a unique it (eg the key) so it knows which item in state to update. But this may be wrong, and I would like to do this the proper way. I tried the immutability helper, but had no success.
I will also want to update/add/remove nested items in an immutable array.
I put this in a codeSandbox for ease https://codesandbox.io/s/mz5WnOXn
class App extends React.Component {
...
editTitle = (e,changeKey) => {
this.setState({
movies: update(this.state.movies, {changeKey: {name: {$set: e.target.value}}})
})
console.log('Edit title ran on', key)
};
...
render() {
...
return (
<div>
{movies.map(e => {
return (
<div>
<input key={e.pk} onChange={this.editTitle} value={e.name} changeKey={e.pk} type="text" />
With genres:
{e.genres.map(x => {
return (
<span key={x.pk}>
<input onChange={this.editGenres} value={x.name} changeKey={x.pk} type="text" />
</span>
);
})}
</div>
);
})}
</div>
);
}
}
Couple of things,
1. By looking at your data i don't see any pk property maybe its a typo (are you trying to use the id property instead?).
2. The key prop should be on the root element that you return on each iteration of your map function.
3. You can't just add none native attributes to a native Html element instead you can use the data-* like data-changeKey and access it via e.target.getAttribute('data-changeKey')
Something like this:
import { render } from 'react-dom';
import React from 'react';
import { reject, pluck, prop, pipe, filter, flatten, uniqBy } from 'ramda';
import { smallData } from './components/data.js';
import './index.css';
import Result from './components/Result';
import update from 'react-addons-update';
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
movies: smallData.movies,
selectedFilters: {},
searchQuery: '',
};
}
editTitle = (e) => {
const attr = e.target.getAttribute('data-changeKey');
this.setState({
movies: update(this.state.movies, {
// what are you trying to do here?
//changeKey: { name: { $set: e.target.value } },
}),
});
console.log('edit title ran on', attr);
};
onSearch = e => {
this.setState({
searchQuery: e.target.value,
});
};
render() {
const { movies } = this.state;
return (
<div>
{movies.map((e, i) => {
return (
<div key={i}>
<input
onChange={this.editTitle}
value={e.name}
data-changeKey={e.id}
type="text"
/>
With genres:
{e.genres.map((x,y) => {
return (
<span key={y}>
<input
onChange={this.editTitle}
value={x.name}
data-changeKey={x.id}
type="text"
/>
</span>
);
})}
Add new genre:
<input type="text" />
</div>
);
})}
</div>
);
}
}
render(<App />, document.getElementById('root'));
Index is what update needs in order to know which data to change.
Firstly, map sure your map is creating an index:
{movies.map((e,index) => {
return (
<input key={e.pk} onChange={e => this.editTitle(e, index)} value={e.name} >
...
Then pass the index to the immutability-helper update like so:
to:
editTitle = (e, index) => {
this.setState({
movies: update(this.state.movies, {[index]: {name: {$set: e.target.value}}})
})

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