Create useContentRect hook

src/hooks/useContentRect/useContentRect.mdx

@@ -0,0 +1,45 @@
+import { Meta } from '@storybook/blocks';
+
+<Meta title="Hooks / useContentRect" />
+
+# useContentRect
+
+The `useContentRect` hook is used to get the size of an HTML element, the `DOMRect` is stored in a
+`RefObject`. It uses the `ResizeObserver` API to observe the element `DOMRect`, the target is
+disconnected when the component unmounts.
+
+## Reference
+
+```ts
+function useContentRect(ref: Unreffable<Element | null>): RefObject<DOMRectReadOnly>;
+```
+
+## Using `useContentRect` with a RefObject
+
+In this example, the `useRef` hook is used to create a `RefObject` for the `div` element which is
+initially set to null. The `useContentRect` hook is then called with the ref variable.
+
+```tsx
+function MyComponent() {
+  const ref = useRef<HTMLDivElement>(null);
+
+  const contentRectRef = useContentRect(ref);
+
+  return <div ref={ref}></div>;
+}
+```
+
+## Using `useContentRect` with an element
+
+In this example, the `useState` hook is used to create a state variable element which is initially
+set to null. The `useContentRect` hook is then called with the element variable.
+
+```tsx
+function MyComponent() {
+  const [element, setElement] = useState<HTMLDivElement | null>(null);
+
+  const contentRectRef = useContentRect(element);
+
+  return <div ref={setElement}></div>;
+}
+```

src/hooks/useContentRect/useContentRect.stories.tsx

@@ -0,0 +1,67 @@
+/* eslint-disable react/jsx-no-literals, react-hooks/rules-of-hooks */
+import type { Meta, StoryObj } from '@storybook/react';
+import { useEffect, useRef } from 'react';
+import { useForceRerender } from '../../index.js';
+import { useContentRect } from './useContentRect.js';
+
+const meta = {
+  title: 'Hooks / useContentRect',
+} satisfies Meta;
+
+export default meta;
+
+type Story = StoryObj<typeof meta>;
+
+export const UseContentRect: Story = {
+  render() {
+    const onClick = useForceRerender();
+    const ref = useRef<HTMLDivElement>(null);
+    const contentRectRef = useContentRect(ref);
+
+    useEffect(() => {
+      const animation = ref.current?.animate(
+        [
+          // keyframes
+          { inlineSize: '300px', blockSize: '300px' },
+          { inlineSize: '500px', blockSize: '500px' },
+          { inlineSize: '300px', blockSize: '300px' },
+        ],
+        {
+          // timing options
+          duration: 2000,
+          iterations: Number.POSITIVE_INFINITY,
+        },
+      );
+
+      return () => animation?.cancel();
+    }, []);
+
+    return (
+      <>
+        <h4>
+          Element size:{' '}
+          <button type="button" onClick={onClick}>
+            Rerender
+          </button>
+        </h4>
+        <div
+          ref={ref}
+          style={{
+            outline: '1px solid red',
+            padding: 18,
+            marginBlock: 20,
+          }}
+        >
+          <code
+            style={{
+              display: 'block',
+              whiteSpace: 'pre',
+            }}
+          >
+            {JSON.stringify(contentRectRef.current, null, 2)}
+          </code>
+        </div>
+      </>
+    );
+  },
+};

src/hooks/useContentRect/useContentRect.ts

@@ -0,0 +1,24 @@
+import { useRef, type RefObject } from 'react';
+import { useMount } from '../../lifecycle/hooks/useMount/useMount.js';
+import { unref, type Unreffable } from '../../utils/unref/unref.js';
+import { useResizeObserver } from '../useResizeObserver/useResizeObserver.js';
+
+/**
+ * A hook that returns a ref object containing the content rectangle of the target
+ * element. The content rectangle is updated whenever the target element is resized.
+ */
+export function useContentRect(
+  target: Unreffable<Element | null>,
+): RefObject<DOMRectReadOnly | null> {
+  const contentRectRef = useRef<DOMRectReadOnly | null>(null);
+
+  useResizeObserver(target, (entries): void => {
+    contentRectRef.current = entries.at(0)?.contentRect ?? null;
+  });
+
+  useMount(() => {
+    contentRectRef.current = unref(target)?.getBoundingClientRect() ?? null;
+  });
+
+  return contentRectRef;
+}

src/hooks/useContentRectState/useContentRectState.mdx

@@ -0,0 +1,43 @@
+import { Meta } from '@storybook/blocks';
+
+<Meta title="Hooks / useContentRectState" />
+
+# useContentRectState
+
+The `useContentRectState` hook is used to get the size of an HTML element, the `DOMRect` is stored
+in a state variable. It uses the `ResizeObserver` API to observe the element `DOMRect`, the target
+is disconnected when the component unmounts.
+
+## Reference
+
+```ts
+function useContentRectState(ref: Unreffable<Element | null>): RefObject<DOMRectReadOnly>;
+```
+
+## Using `useContentRectState` with a RefObject
+
+In this example, the `useRef` hook is used to create a `RefObject` for the `div` element which is
+initially set to null. The `useContentRectState` hook is then called with the ref variable.
+
+```tsx
+function MyComponent() {
+  const ref = useRef<HTMLDivElement>(null);
+  const contentRect = useContentRectState(ref);
+
+  return <div ref={ref}></div>;
+}
+```
+
+## Using `useContentRectState` with an element
+
+In this example, the `useState` hook is used to create a state variable element which is initially
+set to null. The `useContentRectState` hook is then called with the element variable.
+
+```tsx
+function MyComponent() {
+  const [element, setElement] = useState<HTMLDivElement | null>(null);
+  const contentRect = useContentRectState(element);
+
+  return <div ref={setElement}></div>;
+}
+```

src/hooks/useContentRectState/useContentRectState.stories.tsx

@@ -0,0 +1,60 @@
+/* eslint-disable react/jsx-no-literals, react-hooks/rules-of-hooks */
+import type { Meta, StoryObj } from '@storybook/react';
+import { useEffect, useRef } from 'react';
+import { useContentRectState } from './useContentRectState.js';
+
+const meta = {
+  title: 'Hooks / useContentRectState',
+} satisfies Meta;
+
+export default meta;
+
+type Story = StoryObj<typeof meta>;
+
+export const UseContentRectState: Story = {
+  render() {
+    const ref = useRef<HTMLDivElement>(null);
+    const contentRect = useContentRectState(ref);
+
+    useEffect(() => {
+      const animation = ref.current?.animate(
+        [
+          // keyframes
+          { inlineSize: '300px', blockSize: '300px' },
+          { inlineSize: '500px', blockSize: '500px' },
+          { inlineSize: '300px', blockSize: '300px' },
+        ],
+        {
+          // timing options
+          duration: 2000,
+          iterations: Number.POSITIVE_INFINITY,
+        },
+      );
+
+      return () => animation?.cancel();
+    }, []);
+
+    return (
+      <>
+        <h4>Element size:</h4>
+        <div
+          ref={ref}
+          style={{
+            outline: '1px solid red',
+            padding: 18,
+            marginBlock: 20,
+          }}
+        >
+          <code
+            style={{
+              display: 'block',
+              whiteSpace: 'pre',
+            }}
+          >
+            {JSON.stringify(contentRect, null, 2)}
+          </code>
+        </div>
+      </>
+    );
+  },
+};

src/hooks/useContentRectState/useContentRectState.ts

@@ -0,0 +1,26 @@
+import { useRef, useState } from 'react';
+import { useMount } from '../../index.js';
+import { unref, type Unreffable } from '../../utils/unref/unref.js';
+import { useResizeObserver } from '../useResizeObserver/useResizeObserver.js';
+
+/**
+ * A hook that returns the content rectangle of the target element.
+ * The content rectangle is updated whenever the target element is resized.
+ */
+export function useContentRectState(target: Unreffable<Element | null>): DOMRectReadOnly | null {
+  const [contentRect, setContentRect] = useState<DOMRectReadOnly | null>(null);
+  const rafRef = useRef(0);
+
+  useResizeObserver(target, (entries) => {
+    cancelAnimationFrame(rafRef.current);
+    rafRef.current = requestAnimationFrame(() => {
+      setContentRect(entries.at(0)?.contentRect ?? null);
+    });
+  });
+
+  useMount(() => {
+    setContentRect(unref(target)?.getBoundingClientRect() ?? null);
+  });
+
+  return contentRect;
+}

src/index.ts

@@ -10,6 +10,8 @@ export * from './gsap/hooks/useScrollAnimation/useScrollAnimation.js';
 export * from './gsap/utils/getAnimation/getAnimation.js';
 export * from './hocs/ensuredForwardRef/ensuredForwardRef.js';
 export * from './hooks/useClientSideValue/useClientSideValue.js';
+export * from './hooks/useContentRect/useContentRect.js';
+export * from './hooks/useContentRectState/useContentRectState.js';
 export * from './hooks/useEventListener/useEventListener.js';
 export * from './hooks/useForceRerender/useForceRerender.js';
 export * from './hooks/useHasFocus/useHasFocus.js';