I have a chat widget that pulls up an array of messages every time I scroll up. The problem I am facing now is the slider stays fixed at the top when messages load. I want it to focus on the last index element from the previous array. I figured out that I can make dynamic refs by passing index, but I would also need to know what kind of scroll function to use to achieve that
handleScrollToElement(event) {
const tesNode = ReactDOM.findDOMNode(this.refs.test)
if (some_logic){
//scroll to testNode
}
}
render() {
return (
<div>
<div ref="test"></div>
</div>)
}
const ScrollDemo = () => {
const myRef = useRef(null)
const executeScroll = () => myRef.current.scrollIntoView()
// run this function from an event handler or an effect to execute scroll
return (
<>
<div ref={myRef}>Element to scroll to</div>
<button onClick={executeScroll}> Click to scroll </button>
</>
)
}
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class ReadyToScroll extends Component {
constructor(props) {
super(props)
this.myRef = React.createRef()
}
render() {
return <div ref={this.myRef}>Element to scroll to</div>
}
executeScroll = () => this.myRef.current.scrollIntoView()
// run this method to execute scrolling.
}
class ReadyToScroll extends Component {
render() {
return <div ref={ (ref) => this.myRef=ref }>Element to scroll to</div>
}
executeScroll = () => this.myRef.scrollIntoView()
// run this method to execute scrolling.
}
String refs harm performance, aren't composable, and are on their way out (Aug 2018).
string refs have some issues, are considered legacy, and are likely to be removed in one of the future releases. [Official React documentation]
/* css */
html {
scroll-behavior: smooth;
}
We want the ref to be attached to a dom element, not to a react component. So when passing it to a child component we can't name the prop ref.
const MyComponent = () => {
const myRef = useRef(null)
return <ChildComp refProp={myRef}></ChildComp>
}
Then attach the ref prop to a dom element.
const ChildComp = (props) => {
return <div ref={props.refProp} />
}
this worked for me
this.anyRef.current.scrollIntoView({ behavior: 'smooth', block: 'start' })
EDIT: I wanted to expand on this based on the comments.
const scrollTo = (ref) => {
if (ref && ref.current /* + other conditions */) {
ref.current.scrollIntoView({ behavior: 'smooth', block: 'start' })
}
}
<div ref={scrollTo}>Item</div>
Just find the top position of the element you've already determined https://www.w3schools.com/Jsref/prop_element_offsettop.asp then scroll to this position via scrollTo method https://www.w3schools.com/Jsref/met_win_scrollto.asp
Something like this should work:
handleScrollToElement(event) {
const tesNode = ReactDOM.findDOMNode(this.refs.test)
if (some_logic){
window.scrollTo(0, tesNode.offsetTop);
}
}
render() {
return (
<div>
<div ref="test"></div>
</div>)
}
UPDATE:
since React v16.3 the React.createRef() is preferred
constructor(props) {
super(props);
this.myRef = React.createRef();
}
handleScrollToElement(event) {
if (<some_logic>){
window.scrollTo(0, this.myRef.current.offsetTop);
}
}
render() {
return (
<div>
<div ref={this.myRef}></div>
</div>)
}