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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,
});

The most "react" way to pass state to other components

I am fairly new to React. Currently I have two React components - Article.js and ControlForm.js
My render return in Article.js is this:
return (
<div className="article">
{article_wrapper.map( article =>
<div key={article.node.nid} className="article-main-display">
<h1 className="title" dangerouslySetInnerHTML={createMarkup(article.node.title)}/>
<div className="img-div"><img src={article.node.field_image.src} /></div>
<ControlForm />
<div dangerouslySetInnerHTML={createMarkup(article.node.field_user_hsk_level)} />;
<div className="field-name-field-chinese">
<div dangerouslySetInnerHTML={createMarkup(article.node.chinese)} />;
</div>
</div>
)}
</div>
);
The ControlForm.js has several form elements (all of which I'd like to be able to pass along if need be), but this is the main one:
<div className="form-item form-type-select form-group">
<label className="control-label">Font Size</label>
<select
value={this.state.value}
onChange={this.handleSizeSelect}
id="font-size"
className="form-control form-select"
>
<option value="0">Small</option>
<option value="1">Normal</option>
<option value="2">Large</option>
<option value="3">XL</option>
</select>
</div>
I'd like to be able to set a class on one of the divs in the Article.js based on changing a value in the ControlForm.js
What is the most "React" way to do this? Would creating a common parent to both be the best method (right now, their only parent in common is the main App.js)
Sorry if I don't totally understand how this is supposed to work - this is my first React app.
The class associated with the components are ControlForm and withFetching respectively.
EDIT - the demo example below works, but I have some additional issues with how to integrate it properly into my existing code. Here's the existing functions of ControlForm:
class ControlForm extends Component {
constructor() {
super();
this.state = { toggleActive: false, sizeSelect: "0", speed: 1.3, volume: .6};
this.onToggle = this.onToggle.bind(this);
this.handleSpeedChange = this.handleSpeedChange.bind(this);
this.handleVolumeChange = this.handleVolumeChange.bind(this);
this.handleSizeSelect = this.handleSizeSelect.bind(this);
}
onToggle() {
this.setState({ toggleActive: !this.state.toggleActive });
}
handleSizeSelect(event) {
this.setState({ sizeSelect: event.target.value });
this.setState({font: 'large-font'});
parentMethod(event.target.value);
}
handlePlayClick(e) {
e.preventDefault();
voice.playButtonClick();
}
handlePauseClick(e) {
e.preventDefault();
voice.pauseButtonClick();
}
handleStopClick(e) {
e.preventDefault();
voice.stopButtonClick();
}
handleVolumeChange(event) {
console.log(event.target.value);
this.setState({ volume: event.target.value });
}
handleSpeedChange(event) {
console.log(event.target.value);
this.setState({ speed: event.target.value });
}
Articles looks like this:
const withFetching = (url) => (Comp) =>
class WithFetching extends Component {
constructor(props) {
super(props);
this.state = {
data: [],
isLoading: false,
error: null,
dynamicClassName: "parentClass"
};
this.changeClassName = this.changeClassName.bind(this);
}
changeClassName(childData) {
this.setState({
dynamicClassName: childData
});
}
componentDidMount() {
this.setState({ isLoading: true });
fetch(url)
.then(response => {
if (response.ok) {
return response.json();
} else {
throw new Error('Something went wrong ...');
}
})
.then(data => this.setState({ data, isLoading: false }))
.catch(error => this.setState({ error, isLoading: false }));
}
render() {
//return "test";
return <Comp { ...this.props } { ...this.state } />
}
}
function createMarkup(html) {
return {__html: html};
}
function changeClassName(childData) {
console.log("GETS HERE!")
this.setState({
dynamicClassName: childData
});
}
const Articles = ({ data, isLoading, error }) => {
console.log(data);
console.log(isLoading);
const article_wrapper = data.nodes || [];
if (error) {
return <p>{error.message}</p>;
}
if (isLoading) {
return <p>Loading ...</p>;
}
return (
<div className="article">
{article_wrapper.map( article =>
<div key={article.node.nid} className="article-main-display">
<h1 className="title" dangerouslySetInnerHTML={createMarkup(article.node.title)}/>
<div className="img-div"><img src={article.node.field_image.src} /></div>
<ControlForm parentMethod={changeClassName} />
<div dangerouslySetInnerHTML={createMarkup(article.node.field_user_hsk_level)} />;
<div className="field-name-field-chinese">
<div dangerouslySetInnerHTML={createMarkup(article.node.chinese)} />;
</div>
</div>
)}
</div>
);
}
export default withFetching(API)(Articles);
Sorry about all of these questions, I know a lot of this is due to unfamiliarity with React - this is the first thing I've tried to build in React

You want to change parents from his childs.
First, you have to create a handler function at Article.js and pass it to ControlForm.js as a property.
<ControlForm changeDiv={this.changeDiv} />
Then you focus on ControlForm.js, whenever you want to happen, you just execute the function you passed as a the prop changeDiv, like this.props.changeDiv()
See also possible duplicate: How to update parent's state in React?

you can conditionally render a class based on state and your handler was missing the values from the event on the onChange
here's a demo of dynamically changing style base on the state
demo

Article.js ,
class Article extends React.Component {
constructor(props) {
super(props);
this.state = {
dynamicClassName: "parentClass"
}
this.changeClassName = this.changeClassName.bind(this);
}
changeClassName(childData) {
this.setState({
dynamicClassName: childData
});
}
// user dynamicClassName wherever u want .
return ( <
div className = "article" > {
article_wrapper.map(article =>
<
div key = {
article.node.nid
}
className = "article-main-display" >
<
h1 className = "title"
dangerouslySetInnerHTML = {
createMarkup(article.node.title)
}
/> <
div className = "img-div" > < img src = {
article.node.field_image.src
}
/></div >
<
ControlForm parentMethod={this.changeClassName} / >
<
div dangerouslySetInnerHTML = {
createMarkup(article.node.field_user_hsk_level)
}
/>; <
div className = "field-name-field-chinese" >
<
div dangerouslySetInnerHTML = {
createMarkup(article.node.chinese)
}
/>; < /
div > <
/div>
)
} <
/div>
);
}
In ControlForm js ,
class ControlForm extends React.Component {
constructor(props) {
super(props);
this.state = {
}
this.handleSizeSelect= this.handleSizeSelect.bind(this);
}
handleSizeSelect() {
this.props.parentMethod(this.state.value);
}
render() {
return (
<div className="form-item form-type-select form-group">
<label className="control-label">Font Size</label>
<select
value={this.state.value}
onChange={this.handleSizeSelect}
id="font-size"
className="form-control form-select"
>
<option value="0">Small</option>
<option value="1">Normal</option>
<option value="2">Large</option>
<option value="3">XL</option>
</select>
</div>
);
}
}

ReactJS: how to map JSON elements sequentially and show the hidden div on click

I'm trying to load items from JSON and toggle a dropdown div with description on click. While I can display elements sequentially (ex: loc1 & desc1, loc2 & desc2) on static divs I'm having trouble finding out how to render it properly when the second part (desc) is hidden and only shows when the loc div is clicked.
What would be the best way to map the result so it doesn't show as loc1 & loc2, desc1 & desc2 but as loc1 & desc1, loc2 & desc2?
Code:
var places = {
library: {
location: [
{
loc_name: "library1",
"desc": "desc1 : Modern and spacious building"
},
{
loc_name: "library2",
"desc": "desc2 : A cosy small building"
}
]
}
};
function contentClass(isShow) {
if (isShow) {
return "content";
}
return "content invisible";
}
class Toggle extends React.Component {
constructor(props) {
super(props);
this.state = { isShow: false };
this.handleClick = this.handleClick.bind(this);
}
handleClick() {
this.setState(function (prevState) {
return { isShow: !prevState.isShow };
});
}
render() {
const libraries_desc = places.library.location.map((libr) =>
<div>
<p>{libr.desc}</p>
</div>
);
const lib_names = places.library.location.map((libr) =>
<div>
<p>{libr.loc_name}</p>
</div>
);
return (
<div>
<div className='control' onClick={this.handleClick}>
<h4>{lib_names}</h4>
<div className={contentClass(this.state.isShow)}>{libraries_desc}</div>
</div>
</div>
);
}
}
render((
<Toggle />
), document.getElementById('root'));
Current result:
library1
library2
desc1 : Modern and spacious building
desc 2 : A cosy small building
Desired Result:
library1
desc1 : Modern and spacious building (hidden but shown when clicked)
library2
desc 2 : A cosy small building (hidden but shown when clicked)
Codesandbox

I might try extracting a location into a separate component. By extracting it, each location is responsible for knowing its state. In your case, that means its visibility (controlled by this.state.isShow).
Here's how you could do it:
import React from 'react';
import { render } from 'react-dom';
var places = {
library: {
location: [
{
loc_name: "library1",
"desc": "Modern and spacious building"
},
{
loc_name: "library2",
"desc": "A cosy small building"
}
]
}
};
class Location extends React.Component {
constructor(props) {
super(props);
this.state = { isShow: false };
this.handleClick = this.handleClick.bind(this);
}
handleClick() {
this.setState(function (prevState) {
return { isShow: !prevState.isShow };
});
}
contentClass(isShow) {
if (isShow) {
return "content";
}
return "content invisible";
}
render() {
return (
<div className='control' onClick={this.handleClick}>
<h4>{this.props.desc}</h4>
<div className={this.contentClass(this.state.isShow)}>{this.props.loc_name}</div>
</div>
)
}
}
class Toggle extends React.Component {
constructor(props) {
super(props);
}
render() {
const locations = places.library.location.map(location => {
return <Location {...location} />
})
return (
<div>
{locations}
</div>
);
}
}
render((
<Toggle />
), document.getElementById('root'));

Your Toggle Component should be like this.
class Toggle extends React.Component {
constructor(props) {
super(props);
this.state = {
isShow: false,
id: -1, // initial value
};
}
handleClick = (id) => {
this.setState({
isShow: !this.state.isShow,
id: id
});
}
render() {
const { location } = places.library;
const { isShow, id } = this.state;
return (
<div className="control">
{location.map((libr, index) => (
<div key={index} onClick={() => { this.handleClick(index) }}>
<p>{libr.loc_name}</p>
{(isShow && (id === index)) && <p>{libr.desc}</p>}
</div>
))}
</div>
);
}
}
So when you click on the div element. A click event will be triggered called handleClick which will pass the index as a param to the function. which will set isShow to false or truth and vice versa along with the current element you want to show which will be selected through this.state.id. So everytime isShow is true and this.state.id matched index element of the array. Your description will show otherwise it will be hidden as you want.
So your desired result will be something like this.
library1
desc1 : Modern and spacious building (hidden but shown when clicked)
library2
desc 2 : A cosy small building (hidden but shown when clicked)

pass props to dynamic child component

I am trying to create a multiple step form. I have created the form where in each step, corresponding form is rendered dynamically. But I have no idea on how should I pass props to those component so that when returning back, the state gets preserved. I have created a sandbox of it in codesandbox and here it is
https://codesandbox.io/s/8xzm2mxol2
The rendering of form is done the following way
{this.props.steps[this.state.componentState].component}
If the component is rendered as below which is static way, the code would be something like this but I want the dynamic way
if(this.state.componentState === 1) {
<Form1 props={props} />
}
The code is
import React from 'react';
import './fullscreenForm.css';
class MultipleForm extends React.PureComponent {
constructor(props) {
super(props);
this.hidden = {
display: "none"
};
this.state = {
email: 'steve#apple.com',
fname: 'Steve',
lname: 'Jobs',
open: true,
step: 1,
showPreviousBtn: false,
showNextBtn: true,
componentState: 0,
navState: this.getNavStates(0, this.props.steps.length)
};
}
getNavStates(indx, length) {
let styles = [];
for (let i = 0; i < length; i++) {
if (i < indx) {
styles.push("done");
} else if (i === indx) {
styles.push("doing");
} else {
styles.push("todo");
}
}
return { current: indx, styles: styles };
}
checkNavState(currentStep) {
if (currentStep > 0 && currentStep < this.props.steps.length) {
this.setState({
showPreviousBtn: true,
showNextBtn: true
});
} else if (currentStep === 0) {
this.setState({
showPreviousBtn: false,
showNextBtn: true
});
} else {
this.setState({
showPreviousBtn: true,
showNextBtn: false
});
}
}
setNavState(next) {
this.setState({
navState: this.getNavStates(next, this.props.steps.length)
});
if (next < this.props.steps.length) {
this.setState({ componentState: next });
}
this.checkNavState(next);
}
next = () => {
this.setNavState(this.state.componentState + 1);
};
previous = () => {
if (this.state.componentState > 0) {
this.setNavState(this.state.componentState - 1);
}
};
render() {
return (
<div className="parent-container">
<div className="form-block">
{this.props.steps[this.state.componentState].component}
</div>
<div
className="actions"
style={{ display: 'flex', alignItems: 'flex-end', justifyContent: 'flex-end'}}
>
<button
style={this.state.showPreviousBtn ? {} : this.hidden}
className="btn-prev"
onClick={this.previous}
>
Back
</button>
<button
style={this.state.showNextBtn ? {} : this.hidden}
className="btn-next"
onClick={this.next}
>
Continue
</button>
</div>
</div>
);
}
}
export default MultipleForm;
I wanted it in best practice way.

You need to save the values of your form for all the step inputs. Now since on every step you are changing the form component, so you cannot put those values in corresponding form component. Therefore you have to put those values in the parent container (i.e. MultipleForm). Now as you are maintaining a state of values of your child component in parent container, therefore you will have to put some kind of mechanism so that whenever there is any change in input in child component, it should update the corresponding state in parent container. For that you can pass a change handler function to you child component. So your form component should look something like this
<div className="fullscreen-form">
<div className="custom-field">
<label className="custom-label fs-anim-upper" for="email">
What's your email address?
</label>
<input
className="fs-anim-lower"
id="email"
name="email"
type="email"
onChange={this.props.handleChange} // Whenver the input changes then call the parent container's handleChange function so that it can update it's state accordingly
value={this.props.value} // Updated value passed from parent container
placeholder="steve#apple.com"
/>
</div>
</div>
And you will render your form something like this
<Form1 handleChange={this.handleChange} value={this.state.email} />
Here's a working solution of your code:: Code

ReactJS - Set unique state for dynamically generated items

I am fetching some data from the server to populate a list of items, and each item got a onClick event binded to the items id, that changes the UI to be disabled when clicked.
My problem is that the UI changes to disabled perfectly on the first click, but when I go on to click on the next item it resets the first on, so there is only one button disabled at a time. How do I make it so I can disable all the items I want, without resetting the previous ones?
Here is my component:
class Video extends Component {
constructor () {
super()
this.state = {
isDisabled: false
}
}
handleClick(frag, voted, event){
event.preventDefault()
this.setState({
isDisabled: {
[frag]: true
}
})
}
Snippet of what I return in the UI that changes the disabled button
<button onClick={this.handleClick.bind(this, frags.id, frags.voted)} disabled={this.state.isDisabled[frags.id]} className="rating-heart-2">
<i className="fa fa-heart" aria-hidden="true"></i>
</button>
I would really appreciate all tips!

It seems that when you call setState, you are overriding the previous value of the isDisabled.
You can do something like this:
handleClick(frag, voted, event){
event.preventDefault()
this.setState({
isDisabled: {
...this.state.isDisabled,
[frag]: true
}
})
}

The code you provided is a bit confusing because in the jsx you have this.state.hasRated to disable the button and in the handleClick you have a isDisabled object.
I followed the jsx approach and I add the frag id the hasRated object with the value true to disable a button each it is clicked.
You can run the following snippet to see the output of the code:
class Example extends React.Component {
constructor(props) {
super(props);
this.state = {
frags: [],
hasRated: {}
};
this.handleClick = this.handleClick.bind(this);
}
componentDidMount() {
setTimeout(() => {
this.setState({
frags: [{
id: 1,
voted: false
}, {
id: 2,
voted: false
}, {
id: 3,
voted: false
}]
});
}, 500);
}
handleClick(id, voted) {
return (event) => {
this.setState({
hasRated: {
...this.state.hasRated,
[id]: true
}
});
}
}
render() {
const items = this.state.frags.map(frag => ( <
button
key={frag.id}
onClick = {
this.handleClick(frag.id, frag.voted)
}
disabled = {
this.state.hasRated[frag.id]
}
className = "rating-heart-2" >
Button <
/button>
));
return (
<div>
{items}
</div>
);
}
}
ReactDOM.render( < Example / > , document.getElementById('container'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.js"></script>
<div id="container"></div>