fix(compat): correctly merge lifecycle hooks when using Vue.extend (#3762)

fix #3761

packages/runtime-core/src/compat/globalConfig.ts

@@ -113,11 +113,15 @@ export const legacyOptionMergeStrats = {
   watch: mergeObjectOptions
 }
 
+function toArray(target: any) {
+  return isArray(target) ? target : target ? [target] : []
+}
+
 function mergeHook(
   to: Function[] | Function | undefined,
   from: Function | Function[]
 ) {
-  return Array.from(new Set([...(isArray(to) ? to : to ? [to] : []), from]))
+  return Array.from(new Set([...toArray(to), ...toArray(from)]))
 }
 
 function mergeObjectOptions(to: Object | undefined, from: Object | undefined) {

packages/runtime-core/src/componentOptions.ts

@@ -767,55 +767,44 @@ export function applyOptions(
       globalMixins
     )
   }
-  if (beforeMount) {
-    onBeforeMount(beforeMount.bind(publicThis))
-  }
-  if (mounted) {
-    onMounted(mounted.bind(publicThis))
-  }
-  if (beforeUpdate) {
-    onBeforeUpdate(beforeUpdate.bind(publicThis))
-  }
-  if (updated) {
-    onUpdated(updated.bind(publicThis))
-  }
-  if (activated) {
-    onActivated(activated.bind(publicThis))
-  }
-  if (deactivated) {
-    onDeactivated(deactivated.bind(publicThis))
-  }
-  if (errorCaptured) {
-    onErrorCaptured(errorCaptured.bind(publicThis))
-  }
-  if (renderTracked) {
-    onRenderTracked(renderTracked.bind(publicThis))
-  }
-  if (renderTriggered) {
-    onRenderTriggered(renderTriggered.bind(publicThis))
-  }
-  if (beforeUnmount) {
-    onBeforeUnmount(beforeUnmount.bind(publicThis))
-  }
-  if (unmounted) {
-    onUnmounted(unmounted.bind(publicThis))
-  }
-  if (serverPrefetch) {
-    onServerPrefetch(serverPrefetch.bind(publicThis))
+
+  function registerLifecycleHook(
+    register: Function,
+    hook?: Function | Function[]
+  ) {
+    // Array lifecycle hooks are only present in the compat build
+    if (__COMPAT__ && isArray(hook)) {
+      hook.forEach(_hook => register(_hook.bind(publicThis)))
+    } else if (hook) {
+      register((hook as Function).bind(publicThis))
+    }
   }
 
+  registerLifecycleHook(onBeforeMount, beforeMount)
+  registerLifecycleHook(onMounted, mounted)
+  registerLifecycleHook(onBeforeUpdate, beforeUpdate)
+  registerLifecycleHook(onUpdated, updated)
+  registerLifecycleHook(onActivated, activated)
+  registerLifecycleHook(onDeactivated, deactivated)
+  registerLifecycleHook(onErrorCaptured, errorCaptured)
+  registerLifecycleHook(onRenderTracked, renderTracked)
+  registerLifecycleHook(onRenderTriggered, renderTriggered)
+  registerLifecycleHook(onBeforeUnmount, beforeUnmount)
+  registerLifecycleHook(onUnmounted, unmounted)
+  registerLifecycleHook(onServerPrefetch, serverPrefetch)
+
   if (__COMPAT__) {
     if (
       beforeDestroy &&
       softAssertCompatEnabled(DeprecationTypes.OPTIONS_BEFORE_DESTROY, instance)
     ) {
-      onBeforeUnmount(beforeDestroy.bind(publicThis))
+      registerLifecycleHook(onBeforeUnmount, beforeDestroy)
     }
     if (
       destroyed &&
       softAssertCompatEnabled(DeprecationTypes.OPTIONS_DESTROYED, instance)
     ) {
-      onUnmounted(destroyed.bind(publicThis))
+      registerLifecycleHook(onUnmounted, destroyed)
     }
   }