feat(react): add slider component (#644)

packages/utils/src/function/tests/throttle.test.ts

@@ -0,0 +1,101 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { throttle } from '../throttle';
+
+describe('throttle', () => {
+  it('fires on trailing edge after the specified delay', () => {
+    vi.useFakeTimers();
+
+    const callback = vi.fn();
+    const throttled = throttle(callback, 100);
+
+    throttled('first');
+
+    expect(callback).not.toHaveBeenCalled();
+
+    vi.advanceTimersByTime(100);
+
+    expect(callback).toHaveBeenCalledOnce();
+    expect(callback).toHaveBeenCalledWith('first');
+
+    vi.useRealTimers();
+  });
+
+  it('coalesces rapid calls and uses the latest arguments', () => {
+    vi.useFakeTimers();
+
+    const callback = vi.fn();
+    const throttled = throttle(callback, 100);
+
+    throttled('first');
+    throttled('second');
+    throttled('third');
+
+    vi.advanceTimersByTime(100);
+
+    expect(callback).toHaveBeenCalledOnce();
+    expect(callback).toHaveBeenCalledWith('third');
+
+    vi.useRealTimers();
+  });
+
+  it('cancel prevents the pending invocation', () => {
+    vi.useFakeTimers();
+
+    const callback = vi.fn();
+    const throttled = throttle(callback, 100);
+
+    throttled('value');
+    throttled.cancel();
+
+    vi.advanceTimersByTime(200);
+
+    expect(callback).not.toHaveBeenCalled();
+
+    vi.useRealTimers();
+  });
+
+  it('accepts new calls after cancel', () => {
+    vi.useFakeTimers();
+
+    const callback = vi.fn();
+    const throttled = throttle(callback, 100);
+
+    throttled('before-cancel');
+    throttled.cancel();
+
+    throttled('after-cancel');
+    vi.advanceTimersByTime(100);
+
+    expect(callback).toHaveBeenCalledOnce();
+    expect(callback).toHaveBeenCalledWith('after-cancel');
+
+    vi.useRealTimers();
+  });
+
+  it('schedules a new timer after the previous one fires', () => {
+    vi.useFakeTimers();
+
+    const callback = vi.fn();
+    const throttled = throttle(callback, 100);
+
+    throttled('first-batch');
+    vi.advanceTimersByTime(100);
+    expect(callback).toHaveBeenCalledOnce();
+
+    throttled('second-batch');
+    vi.advanceTimersByTime(100);
+
+    expect(callback).toHaveBeenCalledTimes(2);
+    expect(callback).toHaveBeenLastCalledWith('second-batch');
+
+    vi.useRealTimers();
+  });
+
+  it('cancel is a no-op when no timer is pending', () => {
+    const callback = vi.fn();
+    const throttled = throttle(callback, 100);
+
+    expect(() => throttled.cancel()).not.toThrow();
+  });
+});