feat(useThrottleFn): add test cases (#2649)

packages/shared/useThrottleFn/index.test.ts

@@ -0,0 +1,48 @@
+import { promiseTimeout } from '@vueuse/shared'
+import { useThrottleFn } from '../useThrottleFn'
+
+describe('useThrottleFn', () => {
+  it('should be defined', () => {
+    expect(useThrottleFn).toBeDefined()
+  })
+
+  it('should work', async () => {
+    const callback = vi.fn()
+    const ms = 20
+    const run = useThrottleFn(callback, ms)
+    run()
+    run()
+    expect(callback).toHaveBeenCalledTimes(1)
+    await promiseTimeout(ms + 10)
+    run()
+    expect(callback).toHaveBeenCalledTimes(2)
+  })
+
+  it('should work with trailing', async () => {
+    const callback = vi.fn()
+    const ms = 20
+    const run = useThrottleFn(callback, ms, true)
+    run()
+    run()
+    expect(callback).toHaveBeenCalledTimes(1)
+    await promiseTimeout(ms + 10)
+    expect(callback).toHaveBeenCalledTimes(2)
+  })
+
+  it('should work with leading', async () => {
+    const callback = vi.fn()
+    const ms = 20
+    const run = useThrottleFn(callback, ms, false, false)
+    run()
+    run()
+    expect(callback).toHaveBeenCalledTimes(1)
+    await promiseTimeout(ms + 10)
+    run()
+    run()
+    run()
+    expect(callback).toHaveBeenCalledTimes(2)
+    await promiseTimeout(ms + 20)
+    run()
+    expect(callback).toHaveBeenCalledTimes(2)
+  })
+})