From 91cc673d806fe7bf010a23d6e77f02a398841efa Mon Sep 17 00:00:00 2001
From: richard-loafle <44828666+richard-loafle@users.noreply.github.com>
Date: Thu, 6 Feb 2020 16:00:56 +0900
Subject: [PATCH] bug of search is fixed

---
 .../src/lib/components/messages.component.ts  | 64 ++++++++++++-------
 1 file changed, 40 insertions(+), 24 deletions(-)

diff --git a/projects/ucap-webmessenger-ui-chat/src/lib/components/messages.component.ts b/projects/ucap-webmessenger-ui-chat/src/lib/components/messages.component.ts
index c9c1b5d7..6511a7f3 100644
--- a/projects/ucap-webmessenger-ui-chat/src/lib/components/messages.component.ts
+++ b/projects/ucap-webmessenger-ui-chat/src/lib/components/messages.component.ts
@@ -425,29 +425,39 @@ export class MessagesComponent implements OnInit, OnDestroy {
     useSwap: boolean,
     addtionalOffset?: number
   ) {
-    this.preSwapScroll(useHide, useSwap);
-    if (!!preCallback) {
-      preCallback();
-    }
-
-    this.virtualScroller.scrollInto(
-      to,
-      true,
-      undefined !== this.storedScrollItemOffsetTop
-        ? -this.storedScrollItemOffsetTop
-        : undefined !== addtionalOffset
-        ? -addtionalOffset
-        : 0,
-      0,
-      () => {
-        setTimeout(() => {
-          if (!!postCallback) {
-            postCallback();
-          }
-          this.postSwapScroll(useHide, useSwap);
-        });
+    if (!!to) {
+      this.preSwapScroll(useHide, useSwap);
+      if (!!preCallback) {
+        preCallback();
       }
-    );
+
+      this.virtualScroller.scrollInto(
+        to,
+        true,
+        undefined !== this.storedScrollItemOffsetTop
+          ? -this.storedScrollItemOffsetTop
+          : undefined !== addtionalOffset
+          ? -addtionalOffset
+          : 0,
+        0,
+        () => {
+          setTimeout(() => {
+            if (!!postCallback) {
+              postCallback();
+            }
+            this.postSwapScroll(useHide, useSwap);
+          });
+        }
+      );
+    } else {
+      if (!!preCallback) {
+        preCallback();
+      }
+
+      if (!!postCallback) {
+        postCallback();
+      }
+    }
   }
 
   preSwapScroll(useHide: boolean, useSwap: boolean) {
@@ -526,6 +536,10 @@ export class MessagesComponent implements OnInit, OnDestroy {
           false
         );
       } else {
+        if (!this.eventList || 0 === this.eventList.length) {
+          return;
+        }
+
         const lastEvent =
           !!this.eventList && 0 < this.eventList.length
             ? this.eventList[this.eventList.length - 1]
@@ -536,7 +550,9 @@ export class MessagesComponent implements OnInit, OnDestroy {
         }
         const isInViewPortItems = this.isInViewPortItems(lastEvent.seq);
         this.swapScrollTo(
-          this.eventList[this.eventList.length - 1],
+          !!this.gotoEventSeq
+            ? undefined
+            : this.eventList[this.eventList.length - 1],
           () => {},
           () => {
             this.initalized = true;
@@ -547,7 +563,7 @@ export class MessagesComponent implements OnInit, OnDestroy {
           },
           -1 === this.virtualScroller.viewPortInfo.endIndex ||
             !isInViewPortItems,
-          !isInViewPortItems
+          !isInViewPortItems || !!this.gotoEventSeq
         );
       }
     }