refactor(hooks,provider): move reduce motion setter

Since the local storage key is not meant to change between the
components, it should be set directly inside the app file. So
both the local storage and the data attribute should be handle
in a provider.
I also added a custom document because we need a script to
retrieve the stored value in local storage earlier to avoid
flashing on hydration.

3 files changed, 134 insertions, 0 deletions

diff --git a/src/utils/providers/motion-provider/index.ts b/src/utils/providers/motion-provider/index.ts
new file mode 100644
index 0000000..67f493e
--- /dev/null
+++ b/src/utils/providers/motion-provider/index.ts
@@ -0,0 +1 @@
+export * from './motion-provider';
diff --git a/src/utils/providers/motion-provider/motion-provider.test.tsx b/src/utils/providers/motion-provider/motion-provider.test.tsx
new file mode 100644
index 0000000..3a02e6f
--- /dev/null
+++ b/src/utils/providers/motion-provider/motion-provider.test.tsx
@@ -0,0 +1,50 @@
+import { describe, expect, it } from '@jest/globals';
+import { render, screen as rtlScreen } from '@testing-library/react';
+import { type FC, useContext } from 'react';
+import { MotionContext, MotionProvider } from './motion-provider';
+
+const bodyPrefix = 'Motion is reduced:';
+
+const ComponentTest: FC = () => {
+  const { isReduced } = useContext(MotionContext);
+
+  return (
+    <div>
+      {bodyPrefix} {`${isReduced}`}
+    </div>
+  );
+};
+
+describe('MotionProvider', () => {
+  it('uses the default value when the provider is not used', () => {
+    const defaultValue = false;
+
+    render(<ComponentTest />);
+
+    expect(rtlScreen.getByText(new RegExp(bodyPrefix))).toHaveTextContent(
+      `${bodyPrefix} ${defaultValue}`
+    );
+  });
+
+  it('provides the given value to its children and set a matching attribute', () => {
+    const attribute = 'eius';
+    const isReduced = true;
+
+    const { baseElement } = render(
+      <MotionProvider
+        attribute={attribute}
+        storageKey="aperiam"
+        hasReducedMotion={isReduced}
+      >
+        <ComponentTest />
+      </MotionProvider>
+    );
+
+    expect(rtlScreen.getByText(new RegExp(bodyPrefix))).toHaveTextContent(
+      `${bodyPrefix} ${isReduced}`
+    );
+    expect(baseElement.parentElement?.getAttribute(`data-${attribute}`)).toBe(
+      `${isReduced}`
+    );
+  });
+});
diff --git a/src/utils/providers/motion-provider/motion-provider.tsx b/src/utils/providers/motion-provider/motion-provider.tsx
new file mode 100644
index 0000000..dfedcaa
--- /dev/null
+++ b/src/utils/providers/motion-provider/motion-provider.tsx
@@ -0,0 +1,83 @@
+import {
+  type Dispatch,
+  type FC,
+  type ReactNode,
+  type SetStateAction,
+  createContext,
+  useMemo,
+  useCallback,
+  useEffect,
+} from 'react';
+import { getDataAttributeFrom } from '../../helpers';
+import { useLocalStorage } from '../../hooks';
+
+type MotionContextProps = {
+  isReduced: boolean;
+  setIsReduced: Dispatch<SetStateAction<boolean>>;
+  toggleReducedMotion: () => void;
+};
+
+export const MotionContext = createContext<MotionContextProps>({
+  isReduced: false,
+  setIsReduced: (value) => value,
+  toggleReducedMotion: () => null,
+});
+
+const validator = (value: unknown): value is boolean =>
+  typeof value === 'boolean';
+
+export type MotionProviderProps = {
+  /**
+   * The attribute name to append to document root.
+   */
+  attribute: string;
+  /**
+   * The provider children.
+   */
+  children?: ReactNode;
+  /**
+   * Is reduced motion currently active?
+   *
+   * @default false
+   */
+  hasReducedMotion?: boolean;
+  /**
+   * The key to use in local storage.
+   */
+  storageKey: string;
+};
+
+export const MotionProvider: FC<MotionProviderProps> = ({
+  attribute,
+  children,
+  hasReducedMotion = false,
+  storageKey,
+}) => {
+  const [isReduced, setIsReduced] = useLocalStorage(
+    storageKey,
+    hasReducedMotion,
+    validator
+  );
+  const dataAttribute = getDataAttributeFrom(attribute);
+
+  useEffect(() => {
+    if (typeof window !== 'undefined')
+      document.documentElement.setAttribute(dataAttribute, `${isReduced}`);
+
+    return () => {
+      document.documentElement.removeAttribute(dataAttribute);
+    };
+  }, [dataAttribute, isReduced]);
+
+  const toggleReducedMotion = useCallback(() => {
+    setIsReduced((prevState) => !prevState);
+  }, [setIsReduced]);
+
+  const value: MotionContextProps = useMemo(() => {
+    return { isReduced, setIsReduced, toggleReducedMotion };
+  }, [isReduced, setIsReduced, toggleReducedMotion]);
+
+  return (
+    <MotionContext.Provider value={value}>{children}</MotionContext.Provider>
+  );
+};