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Show contents of array in render

I am using MERN stack and Redux. I have created an array in the state 'comments' which is updated via the clickHandler function with elements from the global state (accessed via props). When i try to show the contents of the array in the render i just get the length of it. How would i show the properties of the elements for example title.
import React, { Component } from "react";
import PropTypes from "prop-types";
import GoogleSearch from "./GoogleSearch";
import { connect } from "react-redux";
import { fetchSubjects } from "../../actions/subject";
import { fetchComments } from "../../actions/comment";
import store from "../../store";
class Subject extends Component {
// on loading the subjects and comments
// are fetched from the database
componentDidMount() {
this.props.fetchSubjects();
this.props.fetchComments();
}
constructor(props) {
super(props);
this.state = {
// set inital state for subjects description
// and summary to invisible
viewDesription: -1,
viewSummary: -1,
comments: [],
};
}
componentWillReceiveProps(nextProps) {
// new subject and comments are added to the top
if (nextProps.newPost) {
this.props.subjects.unshift(nextProps.newPost);
}
if (nextProps.newPost) {
this.props.comments.unshift(nextProps.newPost);
}
}
clickHandler = (id) => {
// when a subject title is clicked pass in its id
// and make the desciption visible
const { viewDescription } = this.state;
this.setState({ viewDescription: viewDescription === id ? -1 : id });
// clear the existing comments in state
this.setState({
comments: [],
});
// loop through the comment items in the global state
// and add any with the same subjects id passed in to the array
var i;
for (i = 0; i < this.props.comments.length; i++) {
if (this.props.comments[i].subject == id) {
console.log(this.props.comments[i]);
this.setState({
comments: this.state.comments.unshift(this.props.comments[i]),
});
}
} // set local storage to the id for the subject that has been clicked
localStorage.setItem("passedSubject", id);
};
// hovering on and off subjects toggles the visibility of the summary
hoverHandler = (id) => {
this.setState({ viewSummary: id });
};
hoverOffHandler = () => {
this.setState({ viewSummary: -1 });
};
render() {
const subjectItems = this.props.subjects.map((subject) => {
// if the state equals the id set to visible if not set to invisible
var view = this.state.viewDescription === subject._id ? "" : "none";
var hover = this.state.viewSummary === subject._id ? "" : "none";
var comments = this.state.comments;
return (
<div key={subject._id}>
<div
className="subjectTitle"
onClick={() => this.clickHandler(subject._id)}
onMouseEnter={() => this.hoverHandler(subject._id)}
onMouseLeave={() => this.hoverOffHandler()}
>
<p className="title">{subject.title}</p>
<p className="rating">Rating: {subject.rating}</p>
<p className="summary" style={{ display: hover }}>
{subject.summary}
</p>
</div>
<div className="subjectBody " style={{ display: view }}>
<div className="subjectAuthor">
<p className="author">
Subject created by: {subject.author} on {subject.date}
</p>
<a href="">
<div className="buttonRateSubject">RATE SUBJECT</div>
</a>
</div>
<div className="subjectDescription">
<p className="description">{subject.description}</p>
</div>
<div className="subjectLinks">Links:</div>
<div className="subjectComments">
<p>Comments:</p>
{/* ************HERE*********** */}
<p>{comments}</p>
{/* ********************************* */}
<a href="/addcomment">
<div className="buttonAddComment">ADD COMMENT</div>
</a>
</div>
</div>
</div>
);
});
return (
<div id="Subject">
<GoogleSearch />
{subjectItems}
</div>
);
}
}
Subject.propTypes = {
fetchSubjects: PropTypes.func.isRequired,
fetchComments: PropTypes.func.isRequired,
subjects: PropTypes.array.isRequired,
comments: PropTypes.array.isRequired,
newPost: PropTypes.object,
};
const mapStateToProps = (state) => ({
subjects: state.subjects.items,
newSubject: state.subjects.item,
comments: state.comments.items,
newComment: state.comments.item,
});
// export default Subject;
export default connect(mapStateToProps, { fetchSubjects, fetchComments })(
Subject,
Comment
);

I think I know your problem. You want to render items of an array.
Let me just give you a short overview.
Javascript:
this.setState({
comments: data
});
render (){
return (
<div>
{ this.state.comments.map(c=> <div>{c.body}</div> ) }
</div>
)
}

Thanks guys, i changed the for loop in the clickHandler to this which now has data rendering, it didn't like objects in the array for some reason.
var temp = [];
for (i = 0; i < this.props.comments.length; i++) {
if (this.props.comments[i].subject == id) {
console.log(this.props.comments[i]);
temp.unshift(this.props.comments[i].comment);
temp.unshift(this.props.comments[i].title);
}
}
this.setState({
comments: temp,
});

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>

NotFoundError: Failed to execute 'removeChild' on 'Node' on React with Flickity

I'm building a react application, and on my HomePage, I have the component 'CategoriesList'.
When I'm on the HomePage, the 'Categories List' works well, but when I navigated to ProductDetails page with react-router-dom, I found this error:
"NotFoundError: Failed to execute 'removeChild' on 'Node': The node to be removed is not a child of this node."
'CategoriesList' uses Flickty. I tried to remove Flickity, and... Works well. But I need to use Flickity.
Can anyone help me?
CategoryList Component:
const CategoryList = ({list, popupOpen, refreshProductList}) => {
return (
<Container>
<Slider
options={{
cellAlign: 'center',
draggable: true,
groupCells: true,
contain: false,
pageDots: false,
}}
style={ popupOpen ? ({opacity: 0.05}) : null}
>
{list.map((category, index) => (
<Category key={index}>{category}</Category>
))}
</Slider>
</Container>
);
}
Flickty Slider Component:
import Flickity from 'flickity';
import 'flickity/dist/flickity.min.css';
export default class Slider extends Component {
constructor(props) {
super(props);
this.state = {
flickityReady: false,
};
this.refreshFlickity = this.refreshFlickity.bind(this);
}
componentDidMount() {
this.flickity = new Flickity(this.flickityNode, this.props.options || {});
this.setState({
flickityReady: true,
});
}
refreshFlickity() {
this.flickity.reloadCells();
this.flickity.resize();
this.flickity.updateDraggable();
}
componentWillUnmount() {
this.flickity.destroy();
}
componentDidUpdate(prevProps, prevState) {
const flickityDidBecomeActive = !prevState.flickityReady && this.state.flickityReady;
const childrenDidChange = prevProps.children.length !== this.props.children.length;
if (flickityDidBecomeActive || childrenDidChange) {
this.refreshFlickity();
}
}
renderPortal() {
if (!this.flickityNode) {
return null;
}
const mountNode = this.flickityNode.querySelector('.flickity-slider');
if (mountNode) {
return ReactDOM.createPortal(this.props.children, mountNode);
}
}
render() {
return [
<div style={this.props.style} className={'test'} key="flickityBase" ref={node => (this.flickityNode = node)} />,
this.renderPortal(),
].filter(Boolean);
}
}

If you want to use Flickity along with React instead of creating your own component, I highly recommend using react-flickity-component. It's also easy to use:
Tip: if you use wrapAround option in Flickity set
disableImagesLoaded prop ture (default is false).
import Flickity from 'react-flickity-component'
const flickityOptions = {
autoPlay: 4000,
wrapAround: true
}
function Carousel() {
return (
<Flickity
disableImagesLoaded
options={flickityOptions} // Takes flickity options {}
>
<img src="/images/placeholder.png"/>
<img src="/images/placeholder.png"/>
<img src="/images/placeholder.png"/>
</Flickity>
)
}

I can't implement a Lightbox Gallery on React

I'm follow the steps of this dependencie:
http://jossmac.github.io/react-images/
And it isn't work. No picture showing and there is showing an error message:
index.js:2178 Warning: Failed prop type: The prop onClose is marked
as required in Lightbox, but its value is undefined
Here is my code:
import React, { Component } from "react";
import Lightbox from "react-images";
const URL_INTERIORES = "http://localhost:3001/interiores";
const LIGHTBOX_IMAGE_SET = [
{
src: "/images/int_02.jpg",
caption: "A forest",
// As an array
srcSet: ["/images/int_02.jpg", "/images/int_02.jpg"]
},
{
src: "/images/int_02.jpg",
// As a string
srcSet: "/images/int_02.jpg 1024w, /images/int_02.jpg 800w, /images/int_02.jpg 500w, /images/int_02.jpg 320w"
}
];
class Interiores extends Component {
render() {
const { open } = this.state;
return (
<div>
<div>
<Lightbox
images={LIGHTBOX_IMAGE_SET}
isOpen={this.state.lightboxIsOpen}
onClickPrev={this.gotoPrevLightboxImage}
onClickNext={this.gotoNextLightboxImage}
onClose={this.closeLightbox}
/>
</div>
</div>
);
}
}
export default Interiores;
Does anybody know how to solve it? Tahnk you

Consider adding all the missing handlers & state in your class:
class Interiores extends Component {
state = {
lightboxIsOpen: false
}
gotoPrevLightboxImage() {
// Add the logic here
}
gotoNextLightboxImage() {
// Add the logic here
}
closeLightbox(e) {
// Add the logic here
}
render() {
const { lightboxIsOpen } = this.state;
return (
<div>
<Lightbox
images={LIGHTBOX_IMAGE_SET}
isOpen={lightboxIsOpen}
onClickPrev={() => this.gotoPrevLightboxImage()}
onClickNext={() => this.gotoNextLightboxImage()}
onClose={e => this.closeLightbox(e)}
/>
</div>
);
}
}

Not able to render a React element in React-BootStrap-Table

I want to render buttons in react-bootstrap-table. However, If I pass a React component as the content, the table is render with [object Object].
Here's the code I've tried so far:
// Imports
import React, { Component } from "react";
import { Link } from "react-router-dom";
import { BootstrapTable, TableHeaderColumn } from "react-bootstrap-table";
import "../../../node_modules/react-bootstrap-table/css/react-bootstrap-table.css";
// Exports
export default class Table extends Component {
constructor(props) {
super(props);
// Defaults
this.props.options.search = this.props.options.search ? true : false;
this.props.options.pagination = this.props.options.pagination ? true : false;
}
// Option Buttons
optionButtons = (cell, row) => {
return cell.map(item => {
let key = Object.keys(item)[0];
return (
<Link to={item[key]} className="btn btn-sm">
{key}
</Link>
);
});
};
// This works however
// optionButtons = (cell, row) => {
// return <Link to="/some/route" className="btn btn-sm">Action</Link>;
// };
render() {
let headings = this.props.columns.map((heading, index) => {
let key = Object.keys(heading)[0];
if (index === 0) {
return (
<TableHeaderColumn
key={heading[key]}
dataSort={heading.sortable ? true : false}
dataField={key}
width={
heading.width && !isNaN(heading.width)
? heading.width.toString()
: null
}
isKey
>
{heading[key]}
</TableHeaderColumn>
);
}
if (key === "options") {
return (
<TableHeaderColumn
key={heading[key]}
dataFormat={this.optionButtons}
dataField={key}
width={
heading.width && !isNaN(heading.width)
? heading.width.toString()
: null
}
>
{heading[key]}
</TableHeaderColumn>
);
}
return (
<TableHeaderColumn
key={heading[key]}
dataSort={heading.sortable ? true : false}
dataField={key}
width={
heading.width && !isNaN(heading.width)
? heading.width.toString()
: null
}
>
{heading[key]}
</TableHeaderColumn>
);
});
return (
<BootstrapTable
data={this.props.data}
search={this.props.options.search}
pagination={this.props.options.pagination}
>
{headings}
</BootstrapTable>
);
}
}
The data I am passing to the options key is an array with multiple objects. The problem is in rendering the option buttons. The idea is to be able to pass the number of buttons/link I want from a component and they will be rendered.
This is the data being passed to the options key:
options: [
{ Edit: `/item/${item.id}/edit` },
{ Delete: `/item/${item.id}/delete` }
]

Looks like dataFormat expects a single value, wrap your buttons into a root element (div for example), or into a fragment if supported.