Change css styles from a function in ReactJs - reactjs

When we try to update style of a class we use css() method in a function in jquery
So i want to update a style of a class in Reactjs. Help me to do im new to React
Here is what im trying to do
class Someclass extends Component {
functionA= () =>{
this.functionB();
}
functionB = () =>{
//Here i want to update styles
this.divstyle = {
width: 80%;
}
}
render(){
return(
<div className="div_wrapper" onLoad={this.functionA()}>
<div clasName="innerDiv" style={this.divstyle}></div>
</div>
)
}
}
export default Someclass;

You need to define state for divstyle like below
class Someclass extends Component {
state = {
divstyle : { color: 'blue' }
}
functionA= () =>{
this.functionB();
}
functionB = () =>{
// Call setState method to update the state.
this.setState({
divstyle : {
...this.state.divstyle,
width: 80%
})
}
render(){
return(
<div className="div_wrapper" onLoad={this.functionA()}>
// Now add this.state.divstyle in style property to access styles
<div clasName="innerDiv" style={this.state.divstyle}></div>
</div>
)
}
}
export default Someclass;

Related

ReactJS: Dragging element not working with onmousemove

Im trying to make my own implementation of a drag element by creating a wrapper component that will allow a subcomponent to be dragged. But for some reason, only the first wrapped element can be drag.
class DraggableElement extends Component {
draggable = false;
constructor()
{
super();
this.state = { transform: "translate(0px, 0px)" };
window.onmousemove = (e)=>{
this.log(`should component drag? = ${this.dragging}`);
if(this.dragging){
this.setState({
transform : `translate(${e.clientX}px, ${e.clientY}px)`
});
}
};
}
log(message){
console.log(`${this.props.id}: ${message}`);
}
onMouseDown(e){
this.dragging = true;
this.log(`is draggin? ${this.dragging}`);
}
onMouseUp(e){
this.dragging = false;
this.log("is not dragging");
}
render() {
return (
<div
className="draggable-element"
onMouseDown={(e)=> this.onMouseDown(e)}
onMouseUp={(e)=> this.onMouseUp(e)}
style={this.state}>
{this.props.children}
</div>
);
}
}
The Editor component, where I place all the draggable components:
// imports
import DraggableElement from './DraggableElement';
class Editor extends Component {
render() {
return (
<div>
<DraggableElement id="1">
<select></select>
</DraggableElement>
<DraggableElement id="2">
<select></select>
</DraggableElement>
</div>
);
}
}
And here the css for the 'dragglable-element':
.draggable-element{
border:solid 10px blue;
position:absolute;
display: inline-block;
}
And the App.js:
function App() {
return (
<div className="App">
<Editor></Editor>
</div>
);
}
Ok, i found the error. I should have used window.addEventListener instead of window.onmousemove since i was overriding the previous assingment of the callback.
I changed:
window.onmousemove = (e)=>{
this.log(`should component drag? = ${this.dragging}`);
if(this.dragging){
this.setState({
transform : `translate(${e.clientX}px, ${e.clientY}px)`
});
}
};
To:
window.addEventListener("mousemove",(e=>{
this.log(`show component drag? = ${this.dragging}`);
if(this.dragging){
this.setState({
transform : `translate(${e.clientX}px, ${e.clientY}px)`
});
}
e.preventDefault();
}));
And its working now.

Converting functional component to class component

I have one functional component, but as I need to use now state and more complex logic, I would like to convert it to class component.
But I don't know exactly how to get it working:
My functional component:
import React from 'react';
const FileList = (props) => {
const items = props.items.map((item) => {
return <p key={item.reqId} > { item.name }</ p>
});
return <div>{items}</div>
}
And I tried to do that:
export default class FileL extends React.Component {
constructor(props) {
super(props)
}
render() {
const { items } = this.props;
items = props.items.map((item) => {
return <p key={item.reqId} > {item.name}</ p>
});
return (
<div>{items}</div>
);
}
}
But this is not working.It says "items" is read-only.
I would like to keep the same functionality.
Any ideas?
In your render function
render() {
const { items } = this.props;
items = props.items.map((item) => {
return <p key={item.reqId} > {item.name}</ p>
});
return (
<div>{items}</div>
);
}
items is const so you can't override it. This has nothing to do with React. And you shouldn't reassign a props element, even if its defined with let. You might use the following:
render() {
const { items } = this.props;
return (
<div>
{
items.map((item) => <p key={item.reqId} > {item.name}</ p>)
}
</div>
);
}
You can try this,
export default class FileL extends React.Component {
constructor(props) {
super(props);
}
render() {
return (
<div>
{
this.props.items.map((item) => {
return <p key={item.reqId} > {item.name}</ p>
})
}
</div>
);
}
}
Actually you don't need to convert your component to class based component, as React 16.8 comes with Hooks. Using Hooks you can do whatever you can do with class based component. They let you use state and other React features without writing a class.

During drag and drop if any component hover over the current component, the current component changes it's style.. This is not happening as expected?

import React from 'react';
import { findDOMNode } from 'react-dom';
import { DropTarget } from 'react-dnd';
import HTML5Backend from 'react-dnd-html5-backend';
let newStyle = {'display':'none','left':'0px'} ;
let target = {
hover(props,monitor,component){
newStyle.display = 'block';
newStyle.left = monitor.getClientOffset().x-findDOMNode(component).getBoundingClientRect().left+'px';
//The current mouse position where the "on hover indicator" is expected
return;
},
drop(props, monitor,component) {
newStyle.display = 'none';
newStyle.left = '0px';
return props;
}
}
function collect(connect, monitor) {
return {
connectDropTarget: connect.dropTarget(),
};
}
class component extends React.Component {
constructor(props){
super(props);
}
render = () => {
const { connectDropTarget } = this.props;
return connectDropTarget(
<div>
<Span style = { newStyle }> On hover indicator </span>
// here another component drops wrapped within div!
</div>
)
}
}
export default DropTarget('type', target, collect)(component);
In hover callback if I log my left property of newStyle object it displays the current mouse position as expected but it does not change the style of the span in the render method.
Any help would be appreciated. Thanks in advance.
Just changing the value of a variable used in React won't force a rerender - just changing the value of newStyle won't do anything. To get a React component to rerender itself you need to either a) Call setState or b) Call forceUpdate.
What you could do instead to make it update with the new style on hover would be to add it to the state, and then manipulate that state within the hover function, maybe something like this:
import React from 'react';
import { findDOMNode } from 'react-dom';
import { DropTarget } from 'react-dnd';
import HTML5Backend from 'react-dnd-html5-backend';
let target = {
hover(props,monitor,component) {
let newStyle = {};
newStyle.display = 'block';
newStyle.left = monitor.getClientOffset().x-findDOMNode(component).getBoundingClientRect().left+'px';
component.setState({ style: newStyle });
return;
},
drop(props, monitor,component) {
let newStyle = {}
newStyle.display = 'none';
newStyle.left = '0px';
component.setState({ style: newStyle });
return props;
}
}
function collect(connect, monitor) {
return {
connectDropTarget: connect.dropTarget(),
};
}
class component extends React.Component {
constructor(props){
super(props);
}
state = {
style: { display: 'none', left: '0px' }
}
render = () => {
const { connectDropTarget } = this.props;
return connectDropTarget(
<div>
<Span style={ this.state.style }> On hover indicator </span>
// here another component drops wrapped within div!
</div>
)
}
}
export default DropTarget('type', target, collect)(component);
Note the component.setState() within both the hover and drop functions, this will actually force the component to re-render. 'component' in this instance is actually a reference to the instance of the component, so you have access to it's state from that as well if you need to read the state to do anything else. Check out this section of React's lifecycle docs if you want to get more of an idea what you were doing wrong: https://facebook.github.io/react/docs/react-component.html#setstate
This worked for me:
Instead of using monitor.isDragging() to set the isDragging state use -> !!monitor.getItem(), like so:
const [{ opacity, isDragging }, drag] = useDrag({
type: itemType,
item: () => originalItem,
canDrag,
collect: (monitor: DragSourceMonitor) => ({
opacity: monitor.isDragging() ? 0 : 1,
isDragging: !!monitor.getItem()
})
});
That way the isDragging state will be false whenever no dragging is occurring and true when an item is dragged.
and the hover styles will be applied only when isDragging is false:
<Box
ref={ref}
sx={{
opacity,
...(!isDragging && {
'&:hover': {
borderRadius: '4px',
border: `1px solid blue`
}
})
}}
data-handler-id={handlerId}
>
....
</Box>

Render Clappr player in ReactJS

I'm using Clappr player with ReactJS.
I want Clappr player component appear and destroy when I click to a toggle button. But it seems like when Clappr player is created, the entire page has reload (the toggle button dissapear and appear in a blink). So here is my code:
ClapprComponent.js
import React, { Component } from 'react'
import Clappr from 'clappr'
class ClapprComponent extends Component {
shouldComponentUpdate(nextProps) {
let changed = (nextProps.source != this.props.source)
if (changed) {
this.change(nextProps.source)
}
return false
}
componentDidMount() {
this.change(this.props.source)
}
componentWillUnmount() {
this.destroyPlayer()
}
destroyPlayer = () => {
if (this.player) {
this.player.destroy()
}
this.player = null
}
change = source => {
if (this.player) {
this.player.load(source)
return
}
const { id, width, height } = this.props
this.player = new Clappr.Player({
baseUrl: "/assets/clappr",
parent: `#${id}`,
source: source,
autoPlay: true,
width: width,
height: height
})
}
render() {
const { id } = this.props
return (
<div id={id}></div>
)
}
}
export default ClapprComponent
Video.js
import React, { Component } from 'react'
import { Clappr } from '../components'
class VideoList extends Component {
constructor() {
super()
this.state = {
isActive: false
}
}
toggle() {
this.setState({
isActive: !this.state.isActive
})
}
render() {
const boxStyle = {
width: "640",
height: "360",
border: "2px solid",
margin: "0 auto"
}
return (
<div>
<div style={boxStyle}>
{this.state.isActive ?
<Clappr
id="video"
source="http://qthttp.apple.com.edgesuite.net/1010qwoeiuryfg/sl.m3u8"
width="640"
height="360" />
: ''}
</div>
<button class="btn btn-primary" onClick={this.toggle.bind(this)}>Toggle</button>
</div>
)
}
}
export default VideoList
Anyone can explain why? And how to fix this problem?
Edit 1: I kind of understand why the button is reload. It's because in index.html <head>, I load some css. When the page is re-render, it load the css first, and then execute my app.min.js. The button doesn't reload in a blink if I move the css tags under the <script src="app.min.js"></script>.
But it doesn't solve my problem yet. Because the css files have to put in <head> tags. Any help? :(
Here you have a running (jsbin link) example. I simplified a little bit and it still shows your main requirement:
class ClapprComponent extends React.Component {
componentDidMount(){
const { id, source } = this.props;
this.clappr_player = new Clappr.Player({
parent: `#${id}`,
source: source
});
}
componentWillUnmount() {
this.clappr_player.destroy();
this.clappr_player = null;
}
render() {
const { id } = this.props;
return (
<div>
<p>Active</p>
<p id={id}></p>
</div>
);
}
}
class NotActive extends React.Component {
render() {
return (
<p>Not Active</p>
);
}
}
class App extends React.Component {
constructor(props){
super(props);
this.toggle = this.toggle.bind(this);
this.state = {
isActive: false
}
}
toggle() {
this.setState({
isActive: !this.state.isActive
})
}
render() {
return (
<div>
<h1>Clappr React Demo</h1>
{ this.state.isActive ?
<ClapprComponent
id="video"
source="http://www.html5videoplayer.net/videos/toystory.mp4"
/> :
<NotActive />}
<button onClick={this.toggle}>Toggle</button>
</div>
);
}
}
ReactDOM.render(<App />, document.getElementById('app'));
Also make sure to rename the button class property to className.
Maybe you can work from here to find your exact problem? Hope that helps.
In Clappr's documentation I found a like about how to use clappr with reactjs

How to scroll to bottom in react?

I want to build a chat system and automatically scroll to the bottom when entering the window and when new messages come in. How do you automatically scroll to the bottom of a container in React?
As Tushar mentioned, you can keep a dummy div at the bottom of your chat:
render () {
return (
<div>
<div className="MessageContainer" >
<div className="MessagesList">
{this.renderMessages()}
</div>
<div style={{ float:"left", clear: "both" }}
ref={(el) => { this.messagesEnd = el; }}>
</div>
</div>
</div>
);
}
and then scroll to it whenever your component is updated (i.e. state updated as new messages are added):
scrollToBottom = () => {
this.messagesEnd.scrollIntoView({ behavior: "smooth" });
}
componentDidMount() {
this.scrollToBottom();
}
componentDidUpdate() {
this.scrollToBottom();
}
I'm using the standard Element.scrollIntoView method here.
I just want to update the answer to match the new React.createRef() method, but it's basically the same, just have in mind the current property in the created ref:
class Messages extends React.Component {
const messagesEndRef = React.createRef()
componentDidMount () {
this.scrollToBottom()
}
componentDidUpdate () {
this.scrollToBottom()
}
scrollToBottom = () => {
this.messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' })
}
render () {
const { messages } = this.props
return (
<div>
{messages.map(message => <Message key={message.id} {...message} />)}
<div ref={this.messagesEndRef} />
</div>
)
}
}
UPDATE:
Now that hooks are available, I'm updating the answer to add the use of the useRef and useEffect hooks, the real thing doing the magic (React refs and scrollIntoView DOM method) remains the same:
import React, { useEffect, useRef } from 'react'
const Messages = ({ messages }) => {
const messagesEndRef = useRef(null)
const scrollToBottom = () => {
messagesEndRef.current?.scrollIntoView({ behavior: "smooth" })
}
useEffect(() => {
scrollToBottom()
}, [messages]);
return (
<div>
{messages.map(message => <Message key={message.id} {...message} />)}
<div ref={messagesEndRef} />
</div>
)
}
Also made a (very basic) codesandbox if you wanna check the behaviour https://codesandbox.io/s/scrolltobottomexample-f90lz
Do not use findDOMNode
Class components with ref
class MyComponent extends Component {
componentDidMount() {
this.scrollToBottom();
}
componentDidUpdate() {
this.scrollToBottom();
}
scrollToBottom() {
this.el.scrollIntoView({ behavior: 'smooth' });
}
render() {
return <div ref={el => { this.el = el; }} />
}
}
Function components with hooks:
import React, { useRef, useEffect } from 'react';
const MyComponent = () => {
const divRef = useRef(null);
useEffect(() => {
divRef.current.scrollIntoView({ behavior: 'smooth' });
});
return <div ref={divRef} />;
}
Thanks to #enlitement
we should avoid using findDOMNode,
we can use refs to keep track of the components
render() {
...
return (
<div>
<div
className="MessageList"
ref={(div) => {
this.messageList = div;
}}
>
{ messageListContent }
</div>
</div>
);
}
scrollToBottom() {
const scrollHeight = this.messageList.scrollHeight;
const height = this.messageList.clientHeight;
const maxScrollTop = scrollHeight - height;
this.messageList.scrollTop = maxScrollTop > 0 ? maxScrollTop : 0;
}
componentDidUpdate() {
this.scrollToBottom();
}
reference:
https://facebook.github.io/react/docs/react-dom.html#finddomnode
https://www.pubnub.com/blog/2016-06-28-reactjs-chat-app-infinite-scroll-history-using-redux/
The easiest and best way I would recommend is.
My ReactJS version: 16.12.0
For Class Components
HTML structure inside render() function
render()
return(
<body>
<div ref="messageList">
<div>Message 1</div>
<div>Message 2</div>
<div>Message 3</div>
</div>
</body>
)
)
scrollToBottom() function which will get reference of the element.
and scroll according to scrollIntoView() function.
scrollToBottom = () => {
const { messageList } = this.refs;
messageList.scrollIntoView({behavior: "smooth", block: "end", inline: "nearest"});
}
and call the above function inside componentDidMount() and componentDidUpdate()
For Functional Components (Hooks)
Import useRef() and useEffect()
import { useEffect, useRef } from 'react'
Inside your export function, (same as calling a useState())
const messageRef = useRef();
And let's assume you have to scroll when page load,
useEffect(() => {
if (messageRef.current) {
messageRef.current.scrollIntoView(
{
behavior: 'smooth',
block: 'end',
inline: 'nearest'
})
}
})
OR if you want it to trigger once an action performed,
useEffect(() => {
if (messageRef.current) {
messageRef.current.scrollIntoView(
{
behavior: 'smooth',
block: 'end',
inline: 'nearest'
})
}
},
[stateVariable])
And Finally, to your HTML structure
return(
<body>
<div ref={messageRef}> // <= The only different is we are calling a variable here
<div>Message 1</div>
<div>Message 2</div>
<div>Message 3</div>
</div>
</body>
)
for more explanation about Element.scrollIntoView() visit developer.mozilla.org
More detailed explanation in Callback refs visit reactjs.org
react-scrollable-feed automatically scrolls down to the latest element if the user was already at the bottom of the scrollable section. Otherwise, it will leave the user at the same position. I think this is pretty useful for chat components :)
I think the other answers here will force scroll everytime no matter where the scrollbar was. The other issue with scrollIntoView is that it will scroll the whole page if your scrollable div was not in view.
It can be used like this :
import * as React from 'react'
import ScrollableFeed from 'react-scrollable-feed'
class App extends React.Component {
render() {
const messages = ['Item 1', 'Item 2'];
return (
<ScrollableFeed>
{messages.map((message, i) => <div key={i}>{message}</div>)}
</ScrollableFeed>
);
}
}
Just make sure to have a wrapper component with a specific height or max-height
Disclaimer: I am the owner of the package
I could not get any of below answers to work but simple js did the trick for me:
window.scrollTo({
top: document.body.scrollHeight,
left: 0,
behavior: 'smooth'
});
If you want to do this with React Hooks, this method can be followed. For a dummy div has been placed at the bottom of the chat. useRef Hook is used here.
Hooks API Reference : https://reactjs.org/docs/hooks-reference.html#useref
import React, { useEffect, useRef } from 'react';
const ChatView = ({ ...props }) => {
const el = useRef(null);
useEffect(() => {
el.current.scrollIntoView({ block: 'end', behavior: 'smooth' });
});
return (
<div>
<div className="MessageContainer" >
<div className="MessagesList">
{this.renderMessages()}
</div>
<div id={'el'} ref={el}>
</div>
</div>
</div>
);
}
There are two major problems with the scrollIntoView(...) approach in the top answers:
it's semantically incorrect, as it causes the entire page to scroll if your parent element is scrolled outside the window boundaries. The browser literally scrolls anything it needs to in getting the element visible.
in a functional component using useEffect(), you get unreliable results, at least in Chrome 96.0.4665.45. useEffect() gets called too soon on page reload and the scroll doesn't happen. Delaying scrollIntoView with setTimeout(..., 0) fixes it for page reload, but not first load in a fresh tab, at least for me. shrugs
Here's the solution I've been using, it's solid and is more compatible with older browsers:
function Chat() {
const chatParent = useRef<HTMLDivElement(null);
useEffect(() => {
const domNode = chatParent.current;
if (domNode) {
domNode.scrollTop = domNode.scrollHeight;
}
})
return (
<div ref={chatParent}>
...
</div>
)
}
You can use refs to keep track of the components.
If you know of a way to set the ref of one individual component (the last one), please post!
Here's what I found worked for me:
class ChatContainer extends React.Component {
render() {
const {
messages
} = this.props;
var messageBubbles = messages.map((message, idx) => (
<MessageBubble
key={message.id}
message={message.body}
ref={(ref) => this['_div' + idx] = ref}
/>
));
return (
<div>
{messageBubbles}
</div>
);
}
componentDidMount() {
this.handleResize();
// Scroll to the bottom on initialization
var len = this.props.messages.length - 1;
const node = ReactDOM.findDOMNode(this['_div' + len]);
if (node) {
node.scrollIntoView();
}
}
componentDidUpdate() {
// Scroll as new elements come along
var len = this.props.messages.length - 1;
const node = ReactDOM.findDOMNode(this['_div' + len]);
if (node) {
node.scrollIntoView();
}
}
}
Reference your messages container.
<div ref={(el) => { this.messagesContainer = el; }}> YOUR MESSAGES </div>
Find your messages container and make its scrollTop attribute equal scrollHeight:
scrollToBottom = () => {
const messagesContainer = ReactDOM.findDOMNode(this.messagesContainer);
messagesContainer.scrollTop = messagesContainer.scrollHeight;
};
Evoke above method on componentDidMount and componentDidUpdate.
componentDidMount() {
this.scrollToBottom();
}
componentDidUpdate() {
this.scrollToBottom();
}
This is how I am using this in my code:
export default class StoryView extends Component {
constructor(props) {
super(props);
this.scrollToBottom = this.scrollToBottom.bind(this);
}
scrollToBottom = () => {
const messagesContainer = ReactDOM.findDOMNode(this.messagesContainer);
messagesContainer.scrollTop = messagesContainer.scrollHeight;
};
componentDidMount() {
this.scrollToBottom();
}
componentDidUpdate() {
this.scrollToBottom();
}
render() {
return (
<div>
<Grid className="storyView">
<Row>
<div className="codeView">
<Col md={8} mdOffset={2}>
<div ref={(el) => { this.messagesContainer = el; }}
className="chat">
{
this.props.messages.map(function (message, i) {
return (
<div key={i}>
<div className="bubble" >
{message.body}
</div>
</div>
);
}, this)
}
</div>
</Col>
</div>
</Row>
</Grid>
</div>
);
}
}
I created a empty element in the end of messages, and scrolled to that element. No need of keeping track of refs.
Working Example:
You can use the DOM scrollIntoView method to make a component visible in the view.
For this, while rendering the component just give a reference ID for the DOM element using ref attribute. Then use the method scrollIntoView on componentDidMount life cycle. I am just putting a working sample code for this solution. The following is a component rendering each time a message received. You should write code/methods for rendering this component.
class ChatMessage extends Component {
scrollToBottom = (ref) => {
this.refs[ref].scrollIntoView({ behavior: "smooth" });
}
componentDidMount() {
this.scrollToBottom(this.props.message.MessageId);
}
render() {
return(
<div ref={this.props.message.MessageId}>
<div>Message content here...</div>
</div>
);
}
}
Here this.props.message.MessageId is the unique ID of the particular chat message passed as props
import React, {Component} from 'react';
export default class ChatOutPut extends Component {
constructor(props) {
super(props);
this.state = {
messages: props.chatmessages
};
}
componentDidUpdate = (previousProps, previousState) => {
if (this.refs.chatoutput != null) {
this.refs.chatoutput.scrollTop = this.refs.chatoutput.scrollHeight;
}
}
renderMessage(data) {
return (
<div key={data.key}>
{data.message}
</div>
);
}
render() {
return (
<div ref='chatoutput' className={classes.chatoutputcontainer}>
{this.state.messages.map(this.renderMessage, this)}
</div>
);
}
}
thank you 'metakermit' for his good answer, but I think we can make it a bit better,
for scroll to bottom, we should use this:
scrollToBottom = () => {
this.messagesEnd.scrollIntoView({ behavior: "smooth", block: "end", inline: "nearest" });
}
but if you want to scroll top, you should use this:
scrollToTop = () => {
this.messagesEnd.scrollIntoView({ behavior: "smooth", block: "start", inline: "nearest" });
}
and this codes are common:
componentDidMount() {
this.scrollToBottom();
}
componentDidUpdate() {
this.scrollToBottom();
}
render () {
return (
<div>
<div className="MessageContainer" >
<div className="MessagesList">
{this.renderMessages()}
</div>
<div style={{ float:"left", clear: "both" }}
ref={(el) => { this.messagesEnd = el; }}>
</div>
</div>
</div>
);
}
As another option it is worth looking at react scroll component.
I like doing it the following way.
componentDidUpdate(prevProps, prevState){
this.scrollToBottom();
}
scrollToBottom() {
const {thing} = this.refs;
thing.scrollTop = thing.scrollHeight - thing.clientHeight;
}
render(){
return(
<div ref={`thing`}>
<ManyThings things={}>
</div>
)
}
This is how you would solve this in TypeScript (using the ref to a targeted element where you scroll to):
class Chat extends Component <TextChatPropsType, TextChatStateType> {
private scrollTarget = React.createRef<HTMLDivElement>();
componentDidMount() {
this.scrollToBottom();//scroll to bottom on mount
}
componentDidUpdate() {
this.scrollToBottom();//scroll to bottom when new message was added
}
scrollToBottom = () => {
const node: HTMLDivElement | null = this.scrollTarget.current; //get the element via ref
if (node) { //current ref can be null, so we have to check
node.scrollIntoView({behavior: 'smooth'}); //scroll to the targeted element
}
};
render <div>
{message.map((m: Message) => <ChatMessage key={`chat--${m.id}`} message={m}/>}
<div ref={this.scrollTarget} data-explanation="This is where we scroll to"></div>
</div>
}
For more information about using ref with React and Typescript you can find a great article here.
This works for me
messagesEndRef.current.scrollTop = messagesEndRef.current.scrollHeight
where const messagesEndRef = useRef(); to use
Using React.createRef()
class MessageBox extends Component {
constructor(props) {
super(props)
this.boxRef = React.createRef()
}
scrollToBottom = () => {
this.boxRef.current.scrollTop = this.boxRef.current.scrollHeight
}
componentDidUpdate = () => {
this.scrollToBottom()
}
render() {
return (
<div ref={this.boxRef}></div>
)
}
}
This is modified from an answer above to support 'children' instead of a data array.
Note: The use of styled-components is of no importance to the solution.
import {useEffect, useRef} from "react";
import React from "react";
import styled from "styled-components";
export interface Props {
children: Array<any> | any,
}
export function AutoScrollList(props: Props) {
const bottomRef: any = useRef();
const scrollToBottom = () => {
bottomRef.current.scrollIntoView({
behavior: "smooth",
block: "start",
});
};
useEffect(() => {
scrollToBottom()
}, [props.children])
return (
<Container {...props}>
<div key={'child'}>{props.children}</div>
<div key={'dummy'} ref={bottomRef}/>
</Container>
);
}
const Container = styled.div``;
In order to scroll down to the bottom of the page first we have to select an id which resides at the bottom of the page. Then we can use the document.getElementById to select the id and scroll down using scrollIntoView(). Please refer the below code.
scrollToBottom= async ()=>{
document.getElementById('bottomID').scrollIntoView();
}
I have face this problem in mweb/web.All the solution is good in this page but all the solution is not working while using android chrome browser .
So for mweb and web I got the solution with some minor fixes.
import { createRef, useEffect } from 'react';
import { useSelector } from 'react-redux';
import { AppState } from 'redux/store';
import Message from '../Message/Message';
import styles from './MessageList.module.scss';
const MessageList = () => {
const messagesEndRef: any = createRef();
const { messages } = useSelector((state: AppState) => state?.video);
const scrollToBottom = () => {
//this is not working in mWeb
// messagesEndRef.current.scrollIntoView({
// behavior: 'smooth',
// block: 'end',
// inline: 'nearest',
// });
const scroll =
messagesEndRef.current.scrollHeight -
messagesEndRef.current.clientHeight;
messagesEndRef.current.scrollTo(0, scroll);
};
useEffect(() => {
if (messages.length > 3) {
scrollToBottom();
}
}, [messages]);
return (
<section className={styles.footerTopSection} ref={messagesEndRef} >
{messages?.map((message: any) => (
<Message key={message.id} {...message} />
))}
</section>
);
};
export default MessageList;
This is a great usecase for useLayoutEffect as taught by Kent C. Dodds.
https://kentcdodds.com/blog/useeffect-vs-uselayouteffect
if your effect is mutating the DOM (via a DOM node ref) and the DOM mutation will change the appearance of the DOM node between the time that it is rendered and your effect mutates it, then you don't want to use useEffect.
In my case i was dynamically generating elements at the bottom of a div so i had to add a small timeout.
const bottomRef = useRef<null | HTMLDivElement>(null);
useLayoutEffect(() => {
setTimeout(function () {
if (bottomRef.current) bottomRef.current.scrollTop = bottomRef.current.scrollHeight;
}, 10);
}, [transactionsAmount]);
const scrollingBottom = () => {
const e = ref;
e.current?.scrollIntoView({
behavior: "smooth",
block: "center",
inline: "start",
});
};
useEffect(() => {
scrollingBottom();
});
<span ref={ref}>{item.body.content}</span>
Full version (Typescript):
import * as React from 'react'
export class DivWithScrollHere extends React.Component<any, any> {
loading:any = React.createRef();
componentDidMount() {
this.loading.scrollIntoView(false);
}
render() {
return (
<div ref={e => { this.loading = e; }}> <LoadingTile /> </div>
)
}
}

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