react-multi-ref
v1.0.2
Published
Utility for keeping references to multiple React elements.
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Readme
react-multi-ref
This is a small utility to make it easy for React components to deal with refs on multiple dynamically created elements.
import { useState } from "react";
import MultiRef from "react-multi-ref";
function Foo(props) {
const [itemRefs] = useState(() => new MultiRef());
// Make a 5-item array of divs with keys 0,1,2,3,4
const items = new Array(5).fill(null).map((n, i) => (
<div key={i}>
<input type="text" ref={itemRefs.ref(i)} />
</div>
));
function onClick() {
const parts = [];
itemRefs.map.forEach((input) => {
parts.push(input.value);
});
alert("all input values: " + parts.join(", "));
}
return (
<div>
<button onClick={onClick}>Alert</button>
{items}
</div>
);
}
The multiRef.map
property is a Map object containing entries where the key is
the parameter passed to multiRef.ref(key)
and the value is the ref element
given by React. You can retrieve a specific element by key from the map by using
multiRef.map.get(key)
.
Subsequent calls to multiRef.ref(key)
in later renders with the same key
will return the same value so that React knows that it doesn't need to
update the ref.
Class Component Example
MultiRef is usable as long as you can create an instance of it and persist the
instance for the lifetime of a component. In a function component, you can do this with useState
(not useMemo
, because React is allowed to reset its memory at any time), and in a class component, you can do this by keeping the instance as a property on the class.
import React from "react";
import MultiRef from "react-multi-ref";
class Foo extends React.Component {
#itemRefs = new MultiRef();
render() {
// Make a 5-item array of divs with keys 0,1,2,3,4
const items = new Array(5).fill(null).map((n, i) => (
<div key={i}>
<input type="text" ref={this.#itemRefs.ref(i)} />
</div>
));
return (
<div>
<button onClick={this.#onClick}>Alert</button>
{items}
</div>
);
}
#onClick = () => {
const parts = [];
this.#itemRefs.map.forEach((input) => {
parts.push(input.value);
});
alert("all input values: " + parts.join(", "));
};
}
Types
Both TypeScript and Flow type definitions for this module are included! The type definitions won't require any configuration to use.