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ReactJS rendering issue with edited array

Why does ReactJS remove the last element when the array is different after removing the middle element when using array.splice?
This is my code. I am using React-Redux.
const reducerNotesAndLogin = (state = initialState, action) => {
var tableNotes = "notities";
var tableCategories = "categories";
switch(action.type){
case "CATEGORY_REMOVE":
// Remove the category
var newCategories = state.categories;
console.log("state.categories", state.categories);
console.log("before: ", {newCategories});
var index = 0;
for(var i = 0; i < newCategories.length; i++){
if(newCategories[i].id === action.payload.categoryId){
newCategories.splice(i, 1);
index = i;
i--;
}
}
console.log("after: ", {newCategories});
state = {
...state,
categories: newCategories
}
break;
default:
break;
}
return state;
}
export default reducerNotesAndLogin;
Output below (I deleted the middle element. My web app always removes the last element of the categories (but not from the array).
Step 1: Initial state
Step 2: Remove middle item, expecting the middle item to be removed.
Step 3: Confusion
Why is the array correct, but the view incorrect? I am updating the state.categories correctly right?
This is my render code (as is - without filtering away any other code that mihgt be important)
CategoriesBody:
import React from 'react';
import { connect } from 'react-redux';
import CategoryItem from './CategoryItem';
import Button from './../../Button';
import store from '../../../redux/store-index';
class CategoriesBody extends React.Component {
render(){
return (
<div>
<ul className="list--notes">
{this.props.categories.map((category) => {
if(category.id === undefined){ // No categories
return <li>No categories</li>
} else {
return (
<div>
<CategoryItem category={category} />
<div className="mb-small hidden-sm hidden-md hidden-lg"> </div>
</div>
);
}
})}
</ul>
</div>
);
}
}
function mapStateToProps(state){
return {
categories: state.reducerNotesAndLogin.categories,
categoriesLength: state.reducerNotesAndLogin.categories.length
};
}
export default connect(mapStateToProps)(CategoriesBody);
CategoriesItem.js:
import React from 'react';
import store from './../../../redux/store-index';
import Button from './../../Button';
class CategoryItem extends React.Component {
constructor(props){
super();
this.state = {
edit: false,
categoryName: props.category.categoryName,
categoryColor: props.category.categoryColor
}
this.onClickEdit = this.onClickEdit.bind(this);
this.onChangeCategoryColor = this.onChangeCategoryColor.bind(this);
this.onChangeInputCategoryName = this.onChangeInputCategoryName.bind(this);
this.onClickEditSave = this.onClickEditSave.bind(this);
this.onClickEditCancel = this.onClickEditCancel.bind(this);
}
removeCategory(id, name){
console.log("nsvbsvbfjvbdjhbvv");
store.dispatch({ type: "CATEGORY_REMOVE", payload: {
categoryId: id
}});
// store.dispatch({type: "NOTIFY", payload: {
// type: 'success',
// message: 'Category "' + name + '" removed!'
// }});
}
onClickEdit(){
this.setState({
edit: true
});
}
onChangeCategoryColor(e){
this.setState({
categoryColor: e.target.value
});
}
onChangeInputCategoryName(e){
this.setState({
categoryName: e.target.value
});
}
onClickEditSave(){
this.setState({
edit: false,
categoryName: this.state.categoryName,
categoryColor: this.state.categoryColor
});
store.dispatch({type: "CATEGORY_EDIT", payload: {
categoryId: this.props.category.id,
categoryName: this.state.categoryName,
categoryColor: this.state.categoryColor
}});
store.dispatch({type: "NOTIFY", payload: {
type: "success",
message: "Category saved!"
}});
}
onClickEditCancel(){
this.setState({
edit: false,
categoryName: this.props.category.categoryName,
categoryColor: this.props.category.categoryColor
});
}
render(){
return (
<li key={this.props.category.id} className={this.state.edit === true ? "mt mb" : "flex-justify-between flex-align-center"}>
<div className={this.state.edit === true ? "d-none" : ""}>
<div className="input--color" style={{
backgroundColor: this.state.categoryColor
}}> </div>
{this.state.categoryName}
</div>
{/* Mobile */}
<div className={this.state.edit === true ? "d-none" : "hidden-sm hidden-md hidden-lg"}>
<Button onClick={() => this.onClickEdit()} buttonType="primary">Edit</Button>
<div className="mt-small"> </div>
<Button onClick={() => this.removeCategory(this.props.category.id, this.props.category.categoryName)} type="primary">Remove</Button>
</div>
{/* Tablet and desktop */}
<div className={this.state.edit === true ? "d-none" : "hidden-xs"}>
<div style={{float:'left',}}><Button onClick={() => this.onClickEdit()} buttonType="primary">Edit</Button></div>
<div style={{float:'left',marginLeft:'15px'}}><Button onClick={() => this.removeCategory(this.props.category.id, this.props.category.categoryName)} type="primary">Remove</Button></div>
</div>
{/* EDITING STATE */}
<div className={this.state.edit === true ? "" : "d-none"}>
<div className="row">
<div className="col-xs-12">
<input onChange={this.onChangeCategoryColor} className="input--wide" type="color" value={this.state.categoryColor}
style={{backgroundColor: this.state.categoryColor, height: '30px'}}
/>
<input onChange={this.onChangeInputCategoryName} className="input--wide" type="text" value={this.state.categoryName} />
</div>
</div>
<div className="row mt">
<div className="col-xs-12">
<Button buttonType="primary" onClick={() => this.onClickEditSave()}>Save</Button>
</div>
</div>
<div className="row mt-small">
<div className="col-xs-12">
<Button buttonType="secondary" onClick={() => this.onClickEditCancel()}>Cancel</Button>
</div>
</div>
</div>
</li>
)
}
}
export default CategoryItem;
I think it has something to do with the rendering. Because the arrays are correct when I console.log them. Only the view is different...

Do not modify the state in reducer directly. Create a copy of state value and then modify it.
Change:
var newCategories = state.categories;
To:
var newCategories = [...state.categories];
You should not modify the same array while looping through it.
for (var i = 0; i < newCategories.length; i++) {
if (newCategories[i].id === action.payload.categoryId) {
newCategories.splice(i, 1);
index = i;
i--;
}
}

I got the answer after looking through it with a friend of mine. The solution is pretty simple...
Lesson 101: Make sure that you have a unique "key" property when looping through an array in your UI.
The solution is to add this to my code:
<div key={category.id}>
{this.props.categories.map....
...
</div>

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>
)
}
}

Reactjs - Building form from data set, FormElement not returning to the render function

I am dynamically building a form based on the state build in the constructor. I am having success building the outer html but the inner form html is not rendering. cAN SOMEONE POINT OUT WHAT i AM DOING WRONG HERE?
class Forms extends Component {
constructor(props) {
super(props);
this.state = {
enrollment: {
class: "form-style",
fieldsets: [{
id: "1",
title: "Company Enrollment Form",
formElements: [{
label: "Company Name:",
element: "input",
type: "text",
class: "",
name: "cName",
placeholder: "Your Company's Name *",
required: true,
disabled: false
}, {
label: "Company Type:",
element: "select",
type: "populateDDL",
class: "",
name: "sltCompanyType",
placeholder: "",
required: true,
disabled: false
}]
}]
}
}
}
render() {
let Content = null;
if (this.props.type === "enrollment") {
Content = <EnrollmentForm state={this.state.enrollment} />
} else if (this.props.type === "contact") {
Content = <ContactUsForm />
} else {
Content = <fourOhFour />
}
return (
<div className="container formContent">
{Content}
</div>
);
}
};
function EnrollmentForm(form) {
function renderFieldsets(fieldsets) {
if (fieldsets.length > 0) {
return fieldsets.map((fieldset, index) => (
<Fieldset key={index} set={fieldset} />
));
}
else return [];
}
function renderFormElements(formElements) {
if (formElements.length > 0) {
return formElements.map((formElement, i) => (
<FormElement key={i} set={formElement} />
));
}
else return [];
}
const FormElement = (props, index) => {
console.log(props);
/* ^^^ NOT APPEARING/LOGGING IN THE CONSOLE ^^^ */
if (props.tag === "input") {
return (
<input key={index} name={props.name} />
);
}else if (props.tag === "select") {
return (
<select key={index} />
);
}
};
const Fieldset = (props, index) => {
const elements = renderFormElements(props.set.formElements);
return (
<fieldset key={index}>
<legend>
<span className="number fa fa-address-card"></span>
{props.set.title}
</legend>
</fieldset>
);
};
const fieldsets = renderFieldsets(form.state.fieldsets);
return (
<form className={form.state.class}>
{fieldsets}
</form>
);
}
The FormElement variable is not returning the html... I need to return a different type of html element based on what the tag is in the data model. In the code I have successfully created the outer fieldset but when I go to insert the html elements inside the fieldset, it doesn't do anything. I put a console.log in the code block but apparently even when I try to use the "FormElement" the code isn't firing ...

You have bugs in your code.
Your FormElement should look like
const FormElement = (props, index) => {
console.log(props);
/* ^^^ NOT APPEARING/LOGGING IN THE CONSOLE ^^^ */
if (props.set.element === "input") {//changed from props.tags-- 1
return (
<input key={index} name={props.name} />
);
}else if (props.set.element === "select") {//changed from props.tags --1
return (
<select key={index} />
);
}
return <div>Something which is not select or input</div>; //added a fallback return. --1
};
The bugs that were fixed above are:
(1) props.tags changed to props.set.element. There was no tags component in the props. So none of the if blocks were being rendered and this led to the component not returning anything. This led to an error that said
FormElement(...): A valid React element (or null) must be returned. You may have returned undefined, an array or some other invalid object.
This was resolved by adding the fallback return statement (2).
Your FieldSets should look like
const Fieldset = (props, index) => {
const elements = renderFormElements(props.set.formElements);
return (
<fieldset key={index}>
<legend>
<span className="number fa fa-address-card"></span>
{props.set.title}
</legend>
<div>{elements}</div> // consumed the elements that was created in renderFormElements.
</fieldset>
);
};
The elements variable was never used in render, which led to no FormElements showing up. That was the only error fixed in the above code.
I would suggest cleaning up your code by
Converting EnrollmentForm to a class.
Moving FieldSet and FormElement to seperate classes or at least funtional components
That would make the logic a lot easier to debug in future.

Set state for only for self data into map on reactjs

I have a object's array of users and i'm using map to show them, each user have a option buttons that is 'edit' and 'remove' options each option have a onlclick function that set a state to show another view so the code explain itselft
class App extends React.Component {
state = {
edit: false,
remove: false
}
handleEdit = () => {
this.setState({ edit: true })
}
handleRemove = () => {
this.setState({ remove: true })
}
cancelEdit = () => {
this.setState({ edit: false })
}
cancelRemove = () => {
this.setState({ remove: false })
}
renderEditItem = () => {
const {
state: {
edit,
remove
},
cancelEdit,
cancelRemove,
handleEdit,
handleRemove
} = this
if (edit) {
return (
<div>
<span>Edit view</span>
<br/>
<button onClick={cancelEdit}>Cancel</button>
</div>
)
}
if (remove) {
return (
<div>
<span>Remove view</span>
<br/>
<button onClick={cancelRemove}>Cancel</button>
</div>
)
}
return (
<div>
<button onClick={handleEdit}>Edit</button>
<br/>
<button onClick={handleRemove}>Remove</button>
</div>
)
}
renderUsers = () => {
const {
renderEditItem
} = this
const users = [
{
id: 1,
name: 'User1'
},
{
id: 2,
name: 'User-2'
},
{
id: 3,
name: 'User-3'
}
]
return users.map((user) => {
return (
<ul key={user.id}>
<li>
<div>
<span ref='span'>{user.name}</span>
<br/>
{renderEditItem()}
</div>
</li>
</ul>
)
})
}
render () {
return (
<div>
{this.renderUsers()}
</div>
)
}
}
React.render(
<App />,
document.getElementById('app')
);
JSfiddle: Here
The issue is how can you see is, when i click on the button to set the state for edit or remove option, this will show the view for all the items,
and should be only the view that is clicked, i know the state change to true and is the same for all the items but i don't know how to set the state only for one entry any idea?
Thank you in advance.

Your problem is that the edit/remove state is singular and for the entire list. Each item in the list receives the same state here:
if (edit) {
return (
<div>
<span>Edit view</span>
<br/>
<button onClick={cancelEdit}>Cancel</button>
</div>
)
}
The single edit variable from the state is applied to each list item. If you want to individually set the edit state for each item, it will need to be kept track of with that item.
EX:
const users = [
{
id: 1,
name: 'User1',
edit: true
}]
This way each individual item will be able to tell what state it is in individually. User1 item will have an edit mode that is independent of the other users.
Then you can render something like this:
return users.map((user) => {
return (
<ul key={user.id}>
<li>
<div>
<span ref='span'>{user.name}</span>
<br/>
{user.edit ? 'EDIT MODE' : 'NOT EDIT MODE'}
</div>
</li>
</ul>
)
})

Count checked checkboxes in React.js

I'm using a document structure like this
render() {
return (
<div className="MyComponent">
<ul className="">
{parseRecommendations(this.props.recommendations)}
</ul>
</div>
);
}
function parseRecomendations(recommendations) {
return recommendations.map((recommendation, key) => {
return (<Recommendation data={recommendation} key={key} />);
});
}
Where each Recommendation is its own component containing a checkbox
class Recommendation extends Component {
const recommendation = this.props.data;
const pageUrl = recommendation.url;
return (
<li className="article-item" key={key}>
<div className="article-info">
<input type="checkbox" defaultChecked="checked" aria-described-by={recommendation.pii} />
<a className="journal-title" href={pageUrl} id={recommendation.pii}>{recommendation.title}</a>
</div>
</li>
);
I'd like to have a title saying [Download (x) PDFs], where x is the number of selected checkboxes. How do I find the value of x in this case?

You need to store information about whether input is "checked" in your data. Then, simply count items with truthy "checked" flag.
Here is my solution. You should be able to get principle here and modify your code.
const data = [
{ checked: false, value: 'document 1' },
{ checked: true, value: 'document 2' },
{ checked: true, value: 'document 3' },
{ checked: false, value: 'document 4' },
{ checked: false, value: 'document 5' },
];
const Item = props => (
<div>
<input type="checkbox" checked={props.checked} onChange={props.onCheckChange} />
{ props.value }
</div>
)
var Hello = React.createClass({
getInitialState() {
return {
items: this.props.items.concat(),
};
},
onCheckChange(idx) {
return () => {
const items = this.state.items.concat();
items[idx].checked = !items[idx].checked;
this.setState({items});
}
},
totalChecked() {
return this.state.items.filter(props => props.checked).length;
},
render() {
return (
<div>
{ this.state.items.map((props, idx) => (
<Item {...props} key={idx} onCheckChange={this.onCheckChange(idx)} />
)) }
Total checked: { this.totalChecked() }
</div>
);
}
});
ReactDOM.render(
<Hello items={data} />,
document.getElementById('container')
);

If you just want to get the number of selected check-boxes you can try this
let checkedBoxes = document.querySelectorAll('input[name=chkBox]:checked');
Then get the total checked boxes via checkedBoxes.length
Edit:
Instead of querying whole document. You can get the nearest possible parent via getElementsByClassName or getElementById and then apply querySelectorAll on that element.
e.g
let elem = document.getElementsByClassName("MyComponent");
let checkedBoxes = elem.querySelectorAll('input[name=chkBox]:checked');

You also could obtain the total of selected checkboxes by element type. The "console.log(totalSelectedCheckboxes)" will print them when the state of totalSelectedCheckboxes change using useEffect Hook.
import React, { useState, useEffect } from 'react';
const RenderCheckboxes = () => {
const [totalSelectedCheckboxes, setTotalSelectedCheckboxes] = useState(0);
function handleChk() {
setTotalSelectedCheckboxes(document.querySelectorAll('input[type=checkbox]:checked').length);
}
useEffect(() => {
console.log(totalSelectedCheckboxes);
}, [totalSelectedCheckboxes]);
return (<div>
<div>
<input type="checkbox" value={1} onChange={() => handleChk()} />Chk1
</div>
<div>
<input type="checkbox" value={2} onChange={() => handleChk()} />Chk2
</div>
<div>
<input type="checkbox" value={2} onChange={() => handleChk()} />Chk2
</div>
</div>);
}
export default RenderCheckboxes;