Develop Reference

Problem with loading local images added in object array in react

I made a #JS file called SliderImgs and put an array of objects in that which includes the properties of images of a slider:
const Images=[
{
src:'./files/new-banner-high.jpg',
alt:'banner',
order:'0'
}
]
export default Images
Then I imported this array to a component and then passed that (the array) from props to another component called Slider
import React, { Component } from 'react'
import Images from './SliderImgs'
import Slider from './Slider'
class Body extends Component {
render() {
return (
<div>
<div className="slider">
<Slider pictures={Images}/>
</div>
</div>
)
}
}
export default Body
and finally tried to Print the Image on the screen using the map() method, but I got this error:
Uncaught Error: Cannot find module './files/new-banner-high.jpg'
import React, { Component } from 'react'
class Slider extends Component {
constructor(props){
super(props);
this.state ={
pictures:[]
}
}
static getDerivedStateFromProps(props, state){
return {pictures : props.pictures }
;
}
render() {
return (
<div className="slidercontainer">
{this.state.pictures.map((picture, index)=> {
return(
<img src={require(picture.src)} alt={picture.alt} key={index} />
)
})}
</div>
)
}
}
export default Slider

Normally images should be kept in the public folder.
Move the files directory to the public folder.
Change the array as below.
const Images=[
{
src:'/files/new-banner-high.jpg',
alt:'banner',
order:'0'
}
]
Change the img element like below.
<img src={picture.src} alt={picture.alt} key={index} />

How to pass component to onClick in react

import React from 'react'
export default () => {
function clickHandler() {
console.log('Button clicked')
}
return (
<div>
<button onClick={clickHandler}>Click</button>
</div>
)
}
In the above code we see that a function has been passed to the onClick.In the same way to the onClick I need to pass a diffrent component which is present in the same src. This component consists of a .js and a .css file.Could you please help me out with it. Thanks in advance

If you don't mind using classes instead of functions, your other component should look like this:
import React from 'react'
class ShowThisAfterClick extends React.Component {
return (
<div>
<p>This is what you want to show</p>
</div>
)
}
export default ShowThisAfterClick
And now you should update the component you've shown:
import React from 'react'
import ShowThisAfterClick from './where/you/put/the/ShowThisAfterClick.js'
class Main extends React.Component {
constructor(props){
super(props)
this.state = { isButtonClicked: false }
this.clickHandler = this.clickhandler.bind(this)
}
clickHandler() {
this.setState({ isButtonClicked: true })
}
render() {
const { isButtonClicked } = this.state
return (
<div>
<button onClick={ this.clickHandler }>Click</button>
{ isButtonClicked ? <ShowThisAfterClick /> : ''}
</div>
)
}
}
export default Main
If you want to keep using functions, then I would kindly suggest to read the manual, it is more than well written.

Why isn't the component child rendered?

I have written the following code in APP.js component:
import React from "react";
import Exam from "./exam.js";
export default function App() {
return (
<Exam>
<h1>hashemi</h1>
</Exam>
);
}
And I have written the following code in exam.js component:
import React from "react";
const Exam = ({child}) => {
return (
<div>
<p>parastoo</p>
{child}
</div>
);
};
export default Exam;
But the output shows this:
parastoo
What is the problem? Why doesn't the child <h1> render?

Child components are passes via the children prop to the component, even if there is only a single child:
const Exam = ({children}) => {
return (
<div>
<p>parastoo</p>
{children}
</div>
);
};

It's called props.children. Read from the documentation section Containment.
const Exam = (props) => {
return (
<div>
<p>parastoo</p>
{props.children}
</div>
);
};
I hope this helps!

In React, you can pass props, or properties, to child components. Say you have an App component which renders a child component called CurrentDate which is a stateless functional component. You can pass CurrentDate a date property by writing:
const CurrentDate = (props) => {
return (
<div>
{ /* change code below this line */ }
<p>The current date is: {props.date} </p>
{ /* change code above this line */ }
</div>
);
};
Calender is a parent Component, you can pass Calender a date property by writing
class Calendar extends React.Component {
constructor(props) {
super(props);
}
render() {
return (
<div>
<h3>What date is it?</h3>
{ /* change code below this line */ }
<CurrentDate date={Date()}/>
{ /* change code above this line */ }
</div>
);
}
};

ReactJS How to pass child component values to parent component

I have below codes
chat.js
import React from 'react';
import '../styles/Chat.css';
import Web from '../services/Web';
class Chat extends React.Component {
constructor(props) {
super(props);
this.state = {
msg:''
};
this.sendMessage = this.sendMessage.bind(this);
}
sendMessage () {
this.props.updatecommentText(this.refs.newText.value, this.props.index);
this.setState({ msg: '' });
}
render() {
return (
<div className="Chat-container">
<div className="Chat-row">
<div className="Chat-column">
<div className="Chat-card">
<div className="Chat-body">
<div className="Chat-title">React Based Chatbot</div>
<div className="Chat-messages">
{ this.props.children }
</div>
</div>
<div className="Chat-footer">
<textarea className="Chat-input" ref="newText"></textarea>
<button className="Chat-submit" onClick={this.sendMessage} defaultValue={ this.props.children }>Send</button>
</div>
</div>
</div>
</div>
</div>
);
}
}
export default Chat;
Web.js
import React, { Component } from 'react';
import PropTypes from "prop-types";
import { Link } from "react-router-dom";
import Chat from '../components/Chat';
class Web extends React.Component {
constructor(props){
super(props);
this.state = {
messages:["Hi, How can I help you ?"
]
};
this.sendtobot = this.sendtobot.bind(this);
}
sendtobot(newText, i){
var arr = this.state.messages
arr.push(newText)
this.setState({messages: arr})
}
eachMessage(message, i){
return (<Chat key={i} index={i} updatecommentText={ this.sendtobot.bind(this) }>{ message }</Chat>);
}
render(){
return(
<div>
{this.state.messages.map(this.eachMessage.bind(this))}
</div>
)
}
}
export default Web;
I wanted to take the input from the Chat.js and send it to Web.js and push that value to array messages and then again render that array in the this.props.children in Chat.js
But, while running the code, I am getting an error this.props.updatecommentText is not a function.
Can someone please help me with this.

You have bind this.sendtobot twice. It should be only in the constructor.
like this
eachMessage(message, i){
return (
<Chat key={i} index={i} updatecommentText={this.sendtobot}>
{ message }
</Chat>
);
}

Your code seems to work.
Here is a sandbox with your code.
I'm not sure it works as you would expect, but it works without errors.

By changing this 3 functions in Web component, it starting to look like a chat with only one textarea
sendtobot(newText, i) {
this.setState({ messages: [...this.state.messages, newText] })
}
eachMessage(message, i) {
return (<p>{message}</p>);
}
render() {
return (
<div>
{this.state.messages.map(this.eachMessage.bind(this))}
<Chat updatecommentText={this.sendtobot}/>
</div>
)
}

You can pass child's component state to parent component using redux also as global state.

React-Chat-Widget props not forwarded

I am using the react-chat-widget and trying to call a function in the base class of my application from a custom component rendered by the renderCustomComponent function of the widget.
Here is the code for the base class:
import React, { Component } from 'react';
import { Widget, handleNewUserMessage, addResponseMessage, addUserMessage, renderCustomComponent } from 'react-chat-widget';
import 'react-chat-widget/lib/styles.css';
import Reply from './Reply.js';
class App extends Component {
handleNewUserMessage = (newMessage) => {
renderCustomComponent(Reply, this.correct);
}
correct = () => {
console.log("success");
}
render() {
return (
<div className="App">
<Background />
<Widget
handleNewUserMessage={this.handleNewUserMessage}
/>
</div>
);
}
}
export default App;
And here is the code for the custom component Reply:
import React, { Component } from 'react';
import { Widget, addResponseMessage, renderCustomComponent, addUserMessage } from 'react-chat-widget';
class Reply extends Component {
constructor(props) {
super(props);
}
sendQuickReply = (reply) => {
console.log(this.props); //returns empty object
//this.props.correct(); <-- should be called
};
render() {
return (
<div className="message">
<div key="x" className={"response"}onClick={this.sendQuickReply.bind(this, "xx")}>xx</div>
</div>)
}
}
export default Reply;
According to ReactJS call parent method this should work. However, when I print the this.props object it is empty, although the documentation of the renderCustomComponent method states that the second argument of the component to render are the props that the component needs (in this case the parent class function).
Where have I gone wrong?

The second parameter is considered as props, but it is expected to be an object. you would pass it like
handleNewUserMessage = (newMessage) => {
renderCustomComponent(Reply, {correct: this.correct});
}