feat: new hook useGetSet

src/__docs__/migrating-from-react-use.story.mdx

@@ -557,7 +557,7 @@ Not implemented yet
 
 #### useGetSet
 
-Not implemented yet
+See [useGetSet](/docs/state-useGetSet--example)
 
 #### useGetSetState
 

src/index.ts

@@ -26,6 +26,7 @@ export { useMap } from './useMap/useMap';
 export { useMediatedState } from './useMediatedState/useMediatedState';
 export { usePrevious } from './usePrevious/usePrevious';
 export { useSafeState } from './useSafeState/useSafeState';
+export { useGetSet } from './useGetSet/useGetSet';
 export { useSet } from './useSet/useSet';
 export { useToggle } from './useToggle/useToggle';
 export { useThrottledState } from './useThrottledState/useThrottledState';

src/useGetSet/__docs__/example.stories.tsx

@@ -0,0 +1,12 @@
+import * as React from 'react';
+import { useGetSet } from '../..';
+
+export const Example: React.FC = () => {
+  const [get, set] = useGetSet(0);
+  const onClick = () => {
+    setTimeout(() => {
+      set(get() + 1);
+    }, 1000);
+  };
+  return <button onClick={onClick}>Clicked: {get()}</button>;
+};

src/useGetSet/__docs__/story.mdx

@@ -0,0 +1,38 @@
+import { Canvas, Meta, Story } from '@storybook/addon-docs/blocks';
+import { Example } from './example.stories';
+import { ImportPath } from '../../storybookUtil/ImportPath';
+
+<Meta title="State/useGetSet" component={Example} />
+
+# useGetSet
+
+React state hook that returns state getter function instead of raw state itself, this prevents subtle bugs when state is used in nested functions.
+
+#### Example
+
+<Canvas>
+  <Story story={Example} inline />
+</Canvas>
+
+## Reference
+
+```ts
+export function useGetSet<S>(
+  initialState: IInitialState<S>
+): [get: () => S, set: (nextState: INextState<S>) => void];
+```
+
+#### Importing
+
+<ImportPath />
+
+#### Arguments
+
+- _**initialState**_ _`IInitialState<S>`_ - initial state or initial state setter as for `useState`
+
+#### Return
+
+Returns array alike `useState` does, but instead return a state value it return a getter function.
+
+- _**[0]**_ _`S`_ - getter of current state
+- _**[1]**_ _`(nextState?: INewState<S>) => void`_ - state setter as for `useState`.

src/useGetSet/__tests__/dom.ts

@@ -0,0 +1,62 @@
+import { renderHook, act } from '@testing-library/react-hooks/dom';
+import { useGetSet } from '../..';
+
+const setUp = (initialValue: any) => renderHook(() => useGetSet(initialValue));
+
+beforeEach(() => {
+  jest.useFakeTimers();
+});
+
+describe('useGetSet', () => {
+  it('should be defined', () => {
+    expect(useGetSet).toBeDefined();
+  });
+
+  it('should render', () => {
+    const { result } = setUp('foo');
+    expect(result.error).toBeUndefined();
+  });
+
+  it('should init getter and setter', () => {
+    const { result } = setUp('foo');
+    const [get, set] = result.current;
+    expect(get).toBeInstanceOf(Function);
+    expect(set).toBeInstanceOf(Function);
+  });
+
+  it('should get current value', () => {
+    const { result } = setUp('foo');
+    const [get] = result.current;
+    expect(get()).toBe('foo');
+  });
+
+  it('should set new value', () => {
+    const { result } = setUp('foo');
+    const [get, set] = result.current;
+    act(() => set('bar'));
+    const currentValue = get();
+    expect(currentValue).toBe('bar');
+  });
+
+  it('should get and set expected values when used in nested functions', () => {
+    const { result } = setUp(0);
+    const [get, set] = result.current;
+    const onClick = jest.fn(() => {
+      setTimeout(() => {
+        set(get() + 1);
+      }, 1000);
+    });
+
+    // simulate 3 clicks
+    onClick();
+    onClick();
+    onClick();
+
+    act(() => {
+      jest.runAllTimers();
+    });
+
+    expect(get()).toBe(3);
+    expect(onClick).toHaveBeenCalledTimes(3);
+  });
+});

src/useGetSet/__tests__/ssr.ts

@@ -0,0 +1,62 @@
+import { renderHook, act } from '@testing-library/react-hooks/server';
+import { useGetSet } from '../..';
+
+const setUp = (initialValue: any) => renderHook(() => useGetSet(initialValue));
+
+beforeEach(() => {
+  jest.useFakeTimers();
+});
+
+describe('useGetSet', () => {
+  it('should be defined', () => {
+    expect(useGetSet).toBeDefined();
+  });
+
+  it('should render', () => {
+    const { result } = setUp('foo');
+    expect(result.error).toBeUndefined();
+  });
+
+  it('should init getter and setter', () => {
+    const { result } = setUp('foo');
+    const [get, set] = result.current;
+    expect(get).toBeInstanceOf(Function);
+    expect(set).toBeInstanceOf(Function);
+  });
+
+  it('should get current value', () => {
+    const { result } = setUp('foo');
+    const [get] = result.current;
+    expect(get()).toBe('foo');
+  });
+
+  it('should set new value', () => {
+    const { result } = setUp('foo');
+    const [get, set] = result.current;
+    act(() => set('bar'));
+    const currentValue = get();
+    expect(currentValue).toBe('bar');
+  });
+
+  it('should get and set expected values when used in nested functions', () => {
+    const { result } = setUp(0);
+    const [get, set] = result.current;
+    const onClick = jest.fn(() => {
+      setTimeout(() => {
+        set(get() + 1);
+      }, 1000);
+    });
+
+    // simulate 3 clicks
+    onClick();
+    onClick();
+    onClick();
+
+    act(() => {
+      jest.runAllTimers();
+    });
+
+    expect(get()).toBe(3);
+    expect(onClick).toHaveBeenCalledTimes(3);
+  });
+});

src/useGetSet/useGetSet.ts

@@ -0,0 +1,19 @@
+import { useRef, useCallback } from 'react';
+import { IInitialState, INextState, resolveHookState } from '../util/resolveHookState';
+import { useRerender } from '../index';
+
+export function useGetSet<S>(
+  initialState: IInitialState<S>
+): [get: () => S, set: (nextState: INextState<S>) => void] {
+  const rerender = useRerender();
+  const ref = useRef<S>(resolveHookState(initialState));
+  const get = useCallback(() => ref.current, []);
+  const set = useCallback(
+    (nextState: INextState<S>) => {
+      ref.current = resolveHookState(nextState, ref.current);
+      rerender();
+    },
+    [rerender]
+  );
+  return [get, set];
+}