How to add "refs" dynamically with react hooks?
I created a tiny npm
package that exposes a React Hook
to handle setting and getting refs dynamically as I often run into the same problem.
npm i use-dynamic-refs
Here's a simple example.
import React, { useEffect } from 'react';
import useDynamicRefs from 'use-dynamic-refs';
const Example = () => {
const foo = ['random_id_1', 'random_id_2'];
const [getRef, setRef] = useDynamicRefs();
useEffect(() => {
// Get ref for specific ID
const id = getRef('random_id_1');
console.log(id)
}, [])
return (
<>
{/* Simple set ref. */}
<span ref={setRef('random_id_3')}></span>
{/* Set refs dynamically in Array.map() */}
{ foo.map( eachId => (
<div key={eachId} ref={setRef(eachId)}>Hello {eachId}</div>))}
</>
)
}
export default Example;
Not sure i fully understand your intent, but i think you want something like this:
const {
useState,
useRef,
createRef,
useEffect
} = React;
const data = [
{
text: "test1"
},
{
text: "test2"
}
];
const Component = () => {
const [heights, setHeights] = useState([]);
const elementsRef = useRef(data.map(() => createRef()));
useEffect(() => {
const nextHeights = elementsRef.current.map(
ref => ref.current.getBoundingClientRect().height
);
setHeights(nextHeights);
}, []);
return (
<div>
{data.map((item, index) => (
<div ref={elementsRef.current[index]} key={index} className={`item item-${index}`}>
{`${item.text} - height(${heights[index]})`}
</div>
))}
</div>
);
};
const rootElement = document.getElementById("root");
ReactDOM.render(<Component />, rootElement);
.item {
box-sizing: border-box;
display: flex;
align-items: center;
justify-content: center;
border: 1px solid #ccc;
}
.item-0 {
height: 25px;
}
.item-1 {
height: 50px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.8.6/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.8.6/umd/react-dom.production.min.js"></script>
<div id="root"/>