use native JS private properties

README.md

@@ -10,26 +10,26 @@ import React from 'react';
 import MultiRef from 'react-multi-ref';
 
 class Foo extends React.Component {
-  _itemRefs = new MultiRef();
+  #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)} />
+        <input type="text" ref={this.#itemRefs.ref(i)} />
       </div>
     );
     return (
       <div>
-        <button onClick={this._onClick}>Alert</button>
+        <button onClick={this.#onClick}>Alert</button>
         { items }
       </div>
     );
   }
 
-  _onClick = () => {
+  #onClick = () => {
     const parts = [];
-    this._itemRefs.map.forEach(input => {
+    this.#itemRefs.map.forEach(input => {
       parts.push(input.value)
     });
     alert('all inputs: ' + parts.join(', '));

src/index.js

@@ -5,25 +5,25 @@ type RefFn<V> = (value: V|null) => mixed;
 export default class MultiRef<K,V> {
   map: Map<K,V> = new Map();
 
-  _refFns: Map<K,RefFn<V>> = new Map();
+  #refFns: Map<K,RefFn<V>> = new Map();
 
   ref(key: K): RefFn<V> {
-    const refFn = this._refFns.get(key);
+    const refFn = this.#refFns.get(key);
     if (refFn) {
       return refFn;
     } else {
       const refFn: RefFn<V> = value => {
         if (value == null) {
           // Support for React <=18, which cleans up ref functions by calling them
           // with null.
-          this._refFns.delete(key);
+          this.#refFns.delete(key);
           this.map.delete(key);
         } else {
-          this._refFns.set(key, refFn);
+          this.#refFns.set(key, refFn);
           this.map.set(key, value);
           // React 19+ cleanup support
           return () => {
-            this._refFns.delete(key);
+            this.#refFns.delete(key);
             this.map.delete(key);
           };
         }