fix(useThrottle): fix useThrottle with both leading and trailing (#213)

Author: seungrodotlee

src/hooks/useThrottle/throttle.ts

@@ -35,7 +35,6 @@ export function throttle<F extends (...args: any[]) => void>(
       if (Date.now() - pendingAt >= throttleMs) {
         pendingAt = Date.now();
         debounced.cancel();
-        debounced(...args);
       }
     }
 

src/hooks/useThrottle/useThrottle.spec.ts

@@ -26,4 +26,92 @@ describe('useThrottle', () => {
 
     vi.restoreAllMocks();
   });
+
+  it('should throttle function calls', async () => {
+    const callback = vi.fn();
+    const { result } = await renderHookSSR(() => useThrottle(callback, 100));
+
+    result.current();
+    result.current();
+    result.current();
+
+    expect(callback).toHaveBeenCalledTimes(1);
+  });
+
+  it('should trigger a trailing call after wait time', async () => {
+    vi.useFakeTimers();
+
+    const callback = vi.fn();
+    const throttleMs = 50;
+    const { result } = await renderHookSSR(() => useThrottle(callback, throttleMs));
+
+    result.current();
+    result.current();
+    expect(callback).toBeCalledTimes(1);
+
+    await vi.advanceTimersByTimeAsync(throttleMs + 1);
+    expect(callback).toBeCalledTimes(2);
+
+    vi.useRealTimers();
+  });
+
+  it('should call the function with correct arguments', async () => {
+    const callback = vi.fn();
+    const throttleMs = 50;
+    const { result } = await renderHookSSR(() => useThrottle(callback, throttleMs));
+
+    result.current('test', 123);
+
+    expect(callback).toHaveBeenCalledTimes(1);
+    expect(callback).toHaveBeenCalledWith('test', 123);
+  });
+
+  it('should execute immediately if not called within wait time', async () => {
+    vi.useFakeTimers();
+
+    const callback = vi.fn();
+    const throttleMs = 500;
+    const { result } = await renderHookSSR(() => useThrottle(callback, throttleMs));
+
+    result.current(); // should execute
+    expect(callback).toHaveBeenCalledTimes(1);
+
+    await vi.advanceTimersByTimeAsync(throttleMs + 1);
+
+    result.current(); // should execute again
+    expect(callback).toHaveBeenCalledTimes(2);
+
+    vi.useRealTimers();
+  });
+
+  it('should execute on leading and trailing when called multiple times with leading and trailing', async () => {
+    vi.useFakeTimers();
+
+    const callback = vi.fn();
+    const throttleMs = 50;
+    const { result } = await renderHookSSR(() => useThrottle(callback, throttleMs, { edges: ['leading', 'trailing'] }));
+
+    result.current();
+
+    await vi.advanceTimersByTimeAsync(throttleMs + 1);
+
+    expect(callback).toHaveBeenCalledTimes(1);
+
+    result.current();
+
+    await vi.advanceTimersByTimeAsync(throttleMs);
+
+    expect(callback).toHaveBeenCalledTimes(2);
+
+    result.current();
+    result.current();
+
+    expect(callback).toHaveBeenCalledTimes(3);
+
+    await vi.advanceTimersByTimeAsync(throttleMs);
+
+    expect(callback).toHaveBeenCalledTimes(4);
+
+    vi.useRealTimers();
+  });
 });