Clean up and document.

WordPress · Sep 8, 2024 · 6f3abb7 · 6f3abb7
1 parent 8c2094f
commit 6f3abb7
Showing 1 changed file with 35 additions and 30 deletions.
diff --git a/packages/compose/src/hooks/use-resize-observer/index.ts b/packages/compose/src/hooks/use-resize-observer/index.ts
@@ -13,6 +13,41 @@ import _useLegacyResizeObserver from './_legacy';
  */
 import type { ReactElement } from 'react';
 
+// This is the current implementation of `useResizeObserver`.
+//
+// The legacy implementation is still supported for backwards compatibility.
+// This is achieved by overloading the exported function with both signatures,
+// and detecting which API is being used at runtime.
+function _useResizeObserver< T extends HTMLElement >(
+	callback: ResizeObserverCallback,
+	resizeObserverOptions: ResizeObserverOptions = {}
+): ( element?: T | null ) => void {
+	const callbackEvent = useEvent( callback );
+
+	const observedElementRef = useRef< T | null >();
+	const resizeObserverRef = useRef< ResizeObserver >();
+	return useEvent( ( element?: T | null ) => {
+		if ( element === observedElementRef.current ) {
+			return;
+		}
+		observedElementRef.current = element;
+
+		// Set up `ResizeObserver`.
+		resizeObserverRef.current ??= new ResizeObserver( callbackEvent );
+		const { current: resizeObserver } = resizeObserverRef;
+
+		// Unobserve previous element.
+		if ( observedElementRef.current ) {
+			resizeObserver.unobserve( observedElementRef.current );
+		}
+
+		// Observe new element.
+		if ( element ) {
+			resizeObserver.observe( element, resizeObserverOptions );
+		}
+	} );
+}
+
 /**
  * Sets up a [`ResizeObserver`](https://developer.mozilla.org/en-US/docs/Web/API/Resize_Observer_API)
  * for an HTML or SVG element.
@@ -82,33 +117,3 @@ export default function useResizeObserver< T extends HTMLElement >(
 		? _useResizeObserver( callback, options )
 		: _useLegacyResizeObserver();
 }
-
-function _useResizeObserver< T extends HTMLElement >(
-	callback: ResizeObserverCallback,
-	resizeObserverOptions: ResizeObserverOptions = {}
-): ( element?: T | null ) => void {
-	const callbackEvent = useEvent( callback );
-
-	const observedElementRef = useRef< T | null >();
-	const resizeObserverRef = useRef< ResizeObserver >();
-	return useEvent( ( element?: T | null ) => {
-		if ( element === observedElementRef.current ) {
-			return;
-		}
-		observedElementRef.current = element;
-
-		// Set up `ResizeObserver`.
-		resizeObserverRef.current ??= new ResizeObserver( callbackEvent );
-		const { current: resizeObserver } = resizeObserverRef;
-
-		// Unobserve previous element.
-		if ( observedElementRef.current ) {
-			resizeObserver.unobserve( observedElementRef.current );
-		}
-
-		// Observe new element.
-		if ( element ) {
-			resizeObserver.observe( element, resizeObserverOptions );
-		}
-	} );
-}