fix(useIntervalFn): prevent timer being set after pause is called in cb (#4258)

Co-authored-by: Anthony Fu <anthonyfu117@hotmail.com>

Author: laporchen

packages/shared/useIntervalFn/index.test.ts

@@ -91,6 +91,27 @@ describe('useIntervalFn', () => {
     expect(callback).toHaveBeenCalledTimes(0)
   })
 
+  it('pause in callback', async () => {
+    const pausable = useIntervalFn(() => {
+      callback()
+      pausable.pause()
+    }, 50, { immediateCallback: true, immediate: false })
+
+    pausable.resume()
+    expect(pausable.isActive.value).toBeFalsy()
+    expect(callback).toHaveBeenCalledTimes(1)
+
+    await promiseTimeout(60)
+    expect(callback).toHaveBeenCalledTimes(1)
+
+    pausable.resume()
+    expect(pausable.isActive.value).toBeFalsy()
+    expect(callback).toHaveBeenCalledTimes(2)
+
+    await promiseTimeout(60)
+    expect(callback).toHaveBeenCalledTimes(2)
+  })
+
   it('cant work when interval is negative', async () => {
     const { isActive } = useIntervalFn(callback, -1)
 

packages/shared/useIntervalFn/index.ts

@@ -56,7 +56,8 @@ export function useIntervalFn(cb: Fn, interval: MaybeRefOrGetter<number> = 1000,
     if (immediateCallback)
       cb()
     clean()
-    timer = setInterval(cb, intervalValue)
+    if (isActive.value)
+      timer = setInterval(cb, intervalValue)
   }
 
   if (immediate && isClient)