recei and clear the code

src/app/ui/chat/component/contacts/contacts.page.ts

@@ -121,7 +121,33 @@ export class ContactsPage implements OnInit {
   }
 
   onChange(event) {
+    const textSearch = event.detail.value;
 
+    const filteredUserList: (UserContacts & {isChecked: boolean})[] = this.FilterUserListedByTextSearch(textSearch) as any
+
+    const userContainer = {}
+    for(const user of filteredUserList) {
+      const firstLetter = user.wxFullName.charAt(0)
+      if(!userContainer[firstLetter]) {
+        userContainer[firstLetter] = [user]
+      } else {
+        userContainer[firstLetter].push(user)
+      }
+    }
+    this.userContainer = userContainer
+  }
+
+
+  FilterUserListedByTextSearch(textSearch: string) {
+    return this.allChatUsers.filter( e => e.wxFullName.toLowerCase().includes(textSearch.toLowerCase())).sort((a,b) => {
+      if(a.wxFullName < b.wxFullName) {
+        return -1;
+      }
+      if(a.wxFullName > b.wxFullName) {
+        return 1;
+      }
+      return 0;
+    });
   }
 
   clicked() {}