From c2c9c2b57e5d2e87da99bedb06b9e2d3e48b492e Mon Sep 17 00:00:00 2001
From: Yang Mingshan <y.mingshan3@gmail.com>
Date: Thu, 19 Dec 2019 00:46:59 +0800
Subject: [PATCH] fix(watch): ignore lazy option in simple watch (#546)

* fix(watch): ignore lazy option in simple watch

* test: ignore lazy option in simple watch
---
 .../runtime-core/__tests__/apiWatch.spec.ts   | 19 +++++++++++++++++++
 packages/runtime-core/src/apiWatch.ts         |  2 +-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/packages/runtime-core/__tests__/apiWatch.spec.ts b/packages/runtime-core/__tests__/apiWatch.spec.ts
index 65710c65c5..ed2276f729 100644
--- a/packages/runtime-core/__tests__/apiWatch.spec.ts
+++ b/packages/runtime-core/__tests__/apiWatch.spec.ts
@@ -344,6 +344,25 @@ describe('api: watch', () => {
     expect(cb).toHaveBeenCalled()
   })
 
+  it('ignore lazy', async () => {
+    const count = ref(0)
+    let dummy
+    watch(
+      () => {
+        dummy = count.value
+      },
+      { lazy: true }
+    )
+    expect(dummy).toBeUndefined()
+
+    await nextTick()
+    expect(dummy).toBe(0)
+
+    count.value++
+    await nextTick()
+    expect(dummy).toBe(1)
+  })
+
   it('onTrack', async () => {
     const events: DebuggerEvent[] = []
     let dummy
diff --git a/packages/runtime-core/src/apiWatch.ts b/packages/runtime-core/src/apiWatch.ts
index efd3dfd40a..22828316ed 100644
--- a/packages/runtime-core/src/apiWatch.ts
+++ b/packages/runtime-core/src/apiWatch.ts
@@ -197,7 +197,7 @@ function doWatch(
     scheduler: applyCb ? () => scheduler(applyCb) : scheduler
   })
 
-  if (!lazy) {
+  if (!lazy || !cb) {
     if (applyCb) {
       scheduler(applyCb)
     } else {
-- 
2.47.3