From a961dca7e8871b548c099fafff026772d055a399 Mon Sep 17 00:00:00 2001
From: "Manu Mtz.-Almeida" <manu.mtza@gmail.com>
Date: Thu, 13 Dec 2018 16:43:04 +0100
Subject: [PATCH] fix(angular): lint issue

---
 angular/src/directives/navigation/ion-tabs.ts | 12 +++++-------
 core/src/components/tab-button/tab-button.tsx |  7 +++++++
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/angular/src/directives/navigation/ion-tabs.ts b/angular/src/directives/navigation/ion-tabs.ts
index 959d075bd5..ea2c095e6b 100644
--- a/angular/src/directives/navigation/ion-tabs.ts
+++ b/angular/src/directives/navigation/ion-tabs.ts
@@ -59,13 +59,11 @@ export class IonTabs {
   @HostListener('ionTabButtonClick', ['$event.detail'])
   onTabButtonClick(detail: TabButtonClickDetail) {
     const { tab, selected } = detail;
-    if (tab) {
-      const href = `${this.outlet.tabsPrefix}/${tab}`;
-      const url = selected
-        ? href
-        : this.outlet.getLastUrl(tab) || href;
+    const href = `${this.outlet.tabsPrefix}/${tab}`;
+    const url = selected
+      ? href
+      : this.outlet.getLastUrl(tab) || href;
 
-      this.navCtrl.navigateBack(url, true);
-    }
+    this.navCtrl.navigateBack(url, true);
   }
 }
diff --git a/core/src/components/tab-button/tab-button.tsx b/core/src/components/tab-button/tab-button.tsx
index 3af515941c..ceb6e1f6cc 100644
--- a/core/src/components/tab-button/tab-button.tsx
+++ b/core/src/components/tab-button/tab-button.tsx
@@ -77,6 +77,9 @@ export class TabButton implements ComponentInterface {
     if (this.layout === undefined) {
       this.layout = this.config.get('tabButtonLayout', 'icon-top');
     }
+    if (isNotDefined(this.tab)) {
+      console.error('Missing "tab" property in <ion-tab-button>');
+    }
   }
 
   private get hasLabel() {
@@ -117,3 +120,7 @@ export class TabButton implements ComponentInterface {
     );
   }
 }
+
+function isNotDefined(a: any) {
+  return a == null;
+}