diff --git a/packages/core/src/components.d.ts b/packages/core/src/components.d.ts
index 4ba1aafc566..1cad8ccb66b 100644
--- a/packages/core/src/components.d.ts
+++ b/packages/core/src/components.d.ts
@@ -315,7 +315,7 @@ declare global {
   namespace JSXElements {
     export interface IonBackButtonAttributes extends HTMLAttributes {
       mode?: 'ios' | 'md';
-      text?: string;
+      text?: string|undefined;
     }
   }
 }
@@ -1033,7 +1033,6 @@ declare global {
     export interface IonGestureAttributes extends HTMLAttributes {
       attachTo?: ElementRef;
       autoBlockAll?: boolean;
-      block?: string;
       canStart?: GestureCallback;
       direction?: string;
       disabled?: boolean;
@@ -1712,7 +1711,6 @@ declare global {
     export interface IonMenuButtonAttributes extends HTMLAttributes {
       autoHide?: boolean;
       menu?: string;
-      mode?: 'ios' | 'md';
     }
   }
 }
@@ -2845,7 +2843,7 @@ declare global {
     export interface IonSelectOptionAttributes extends HTMLAttributes {
       disabled?: boolean;
       selected?: boolean;
-      value?: string;
+      value?: string|null;
     }
   }
 }
@@ -2917,7 +2915,7 @@ declare global {
       okText?: string;
       placeholder?: string;
       selectedText?: string;
-      value?: string | string[];
+      value?: string | string[] | null;
     }
   }
 }
diff --git a/packages/core/src/components/back-button/back-button.tsx b/packages/core/src/components/back-button/back-button.tsx
index d03eab13f3d..51dc9606c8b 100644
--- a/packages/core/src/components/back-button/back-button.tsx
+++ b/packages/core/src/components/back-button/back-button.tsx
@@ -1,4 +1,4 @@
-import { Component, Element, Prop, State } from '@stencil/core';
+import { Component, Element, Prop } from '@stencil/core';
 import { Config } from '../../index';
 
 @Component({
@@ -13,7 +13,7 @@ import { Config } from '../../index';
 })
 export class BackButton {
 
-  @State() custom: boolean;
+  private custom = true;
 
   /**
    * The mode determines which platform styles to use.
@@ -26,7 +26,7 @@ export class BackButton {
    * The text property is used to provide custom text for the back button while using the
    * default look-and-feel
    */
-  @Prop() text: string = null;
+  @Prop() text: string|undefined;
 
   @Prop({ context: 'config' }) config: Config;
 
diff --git a/packages/core/src/components/back-button/readme.md b/packages/core/src/components/back-button/readme.md
index 9c17c6d2479..73ec78b5165 100644
--- a/packages/core/src/components/back-button/readme.md
+++ b/packages/core/src/components/back-button/readme.md
@@ -66,7 +66,7 @@ For more information, see [Platform Styles](/docs/theming/platform-specific-styl
 
 #### text
 
-string
+
 
 The text property is used to provide custom text for the back button while using the
 default look-and-feel
@@ -85,7 +85,7 @@ For more information, see [Platform Styles](/docs/theming/platform-specific-styl
 
 #### text
 
-string
+
 
 The text property is used to provide custom text for the back button while using the
 default look-and-feel
diff --git a/packages/core/src/components/content/content.tsx b/packages/core/src/components/content/content.tsx
index eb57ef18524..04976acc5b4 100644
--- a/packages/core/src/components/content/content.tsx
+++ b/packages/core/src/components/content/content.tsx
@@ -8,10 +8,10 @@ import { getPageElement } from '../../utils/helpers';
 })
 export class Content {
 
-  private cTop = 0;
-  private cBottom = 0;
+  private cTop = -1;
+  private cBottom = -1;
   private dirty = false;
-  private scrollEl: HTMLIonScrollElement|null;
+  private scrollEl: HTMLIonScrollElement;
 
   mode: string;
   color: string;
@@ -44,12 +44,11 @@ export class Content {
   }
 
   componentDidLoad() {
-    this.scrollEl = this.el.querySelector('ion-scroll');
     this.resize();
   }
 
   componentDidUnload() {
-    this.scrollEl = null;
+    this.scrollEl = undefined as any;
   }
 
   /**
@@ -94,7 +93,7 @@ export class Content {
         this.dom.write(this.writeDimensions.bind(this));
       });
     } else {
-      this.cTop = this.cBottom = null;
+      this.cTop = this.cBottom = -1;
       this.dom.write(() => this.scrollEl && this.scrollEl.removeAttribute('style'));
     }
   }
@@ -132,6 +131,7 @@ export class Content {
 
     return [
       <ion-scroll
+        ref={el => this.scrollEl = el as any}
         mode={this.mode}
         scrollEvents={this.scrollEvents}
         forceOverscroll={this.forceOverscroll}>
diff --git a/packages/core/src/components/fab/fab.tsx b/packages/core/src/components/fab/fab.tsx
index bd48717fbd6..9d91638c005 100644
--- a/packages/core/src/components/fab/fab.tsx
+++ b/packages/core/src/components/fab/fab.tsx
@@ -24,8 +24,10 @@ export class Fab {
 
   render() {
     const fab = this.el.querySelector('ion-fab-button');
-    fab.toggleActive = this.toggleActive;
-    fab.activated = this.activated;
+    if (fab) {
+      fab.toggleActive = this.toggleActive;
+      fab.activated = this.activated;
+    }
 
     const lists = this.el.querySelectorAll('ion-fab-list');
     for (let i = 0, length = lists.length; i < length; i += 1) {
diff --git a/packages/core/src/components/gesture-controller/gesture-controller-utils.ts b/packages/core/src/components/gesture-controller/gesture-controller-utils.ts
index 1b5d037d5d4..90d41b125e1 100644
--- a/packages/core/src/components/gesture-controller/gesture-controller-utils.ts
+++ b/packages/core/src/components/gesture-controller/gesture-controller-utils.ts
@@ -1,7 +1,7 @@
-import { GestureController } from './gesture-controller';
+import { GestureController } from '../..';
 
 export class GestureDelegate {
-  private ctrl: GestureController|null;
+  private ctrl: GestureController|undefined;
 
   constructor(
     ctrl: any,
@@ -54,14 +54,14 @@ export class GestureDelegate {
 
   destroy() {
     this.release();
-    this.ctrl = null;
+    this.ctrl = undefined;
   }
 }
 
 
 export class BlockerDelegate {
 
-  private ctrl: any|null;
+  private ctrl: GestureController|undefined;
 
   constructor(
     private id: number,
@@ -103,7 +103,7 @@ export class BlockerDelegate {
 
   destroy() {
     this.unblock();
-    this.ctrl = null;
+    this.ctrl = undefined;
   }
 }
 
diff --git a/packages/core/src/components/gesture/gesture.tsx b/packages/core/src/components/gesture/gesture.tsx
index f6dff99f9c1..15c125540ed 100644
--- a/packages/core/src/components/gesture/gesture.tsx
+++ b/packages/core/src/components/gesture/gesture.tsx
@@ -1,6 +1,6 @@
 import { Component, Event, EventEmitter, EventListenerEnable, Listen, Prop, Watch } from '@stencil/core';
 import { ElementRef, assert, now, updateDetail } from '../../utils/helpers';
-import { BlockerConfig, BlockerDelegate, DomController, GestureDelegate } from '../../index';
+import { BlockerDelegate, DomController, GestureDelegate } from '../../index';
 import { BLOCK_ALL } from '../gesture-controller/gesture-controller-utils';
 import { PanRecognizer } from './recognizers';
 
@@ -10,7 +10,7 @@ import { PanRecognizer } from './recognizers';
 })
 export class Gesture {
 
-  private detail: GestureDetail = {};
+  private detail: GestureDetail;
   private positions: number[] = [];
   private gesture: GestureDelegate;
   private lastTouch = 0;
@@ -20,7 +20,7 @@ export class Gesture {
   private hasStartedPan = false;
   private hasFiredStart = true;
   private isMoveQueued = false;
-  private blocker: BlockerDelegate;
+  private blocker: BlockerDelegate|undefined;
 
   @Prop({ connect: 'ion-gesture-controller' }) gestureCtrl: HTMLIonGestureControllerElement;
   @Prop({ context: 'dom' }) dom: DomController;
@@ -29,7 +29,6 @@ export class Gesture {
   @Prop() disabled = false;
   @Prop() attachTo: ElementRef = 'child';
   @Prop() autoBlockAll = false;
-  @Prop() block: string = null;
   @Prop() disableScroll = false;
   @Prop() direction = 'x';
   @Prop() gestureName = '';
@@ -72,6 +71,24 @@ export class Gesture {
    */
   @Event() ionPress: EventEmitter;
 
+  constructor() {
+    this.detail = {
+      type: 'pan',
+      startX: 0,
+      startY: 0,
+      startTimeStamp: 0,
+      currentX: 0,
+      currentY: 0,
+      velocityX: 0,
+      velocityY: 0,
+      deltaX: 0,
+      deltaY: 0,
+      timeStamp: 0,
+      event: undefined as any,
+      data: undefined,
+    };
+  }
+
   componentWillLoad() {
     return this.gestureCtrl.create({
       name: this.gestureName,
@@ -94,7 +111,9 @@ export class Gesture {
     this.disabledChanged(this.disabled);
 
     if (this.autoBlockAll) {
-      this.setBlocker(BLOCK_ALL).then(b => b.block());
+      this.gestureCtrl.componentOnReady()
+        .then(ctrl => ctrl.createBlocker(BLOCK_ALL))
+        .then(blocker => this.blocker = blocker);
     }
   }
 
@@ -109,23 +128,6 @@ export class Gesture {
     }
   }
 
-  @Watch('block')
-  protected blockChanged(block: string) {
-    this.setBlocker({ disable: block.split(',')});
-  }
-
-  private setBlocker(config: BlockerConfig) {
-    if (this.blocker) {
-      this.blocker.destroy();
-    }
-    if (config) {
-      return this.gestureCtrl.componentOnReady()
-        .then(ctrl => ctrl.createBlocker(config))
-        .then(blocker => this.blocker = blocker);
-    }
-    return Promise.resolve(null);
-  }
-
   // DOWN *************************
 
   @Listen('touchstart', { passive: true, enabled: false })
@@ -296,7 +298,7 @@ export class Gesture {
   }
 
   private tryToCapturePan(): boolean {
-    if (this.gesture && !this.gesture.capture()) {
+    if (!this.gesture.capture()) {
       return false;
     }
     this.hasCapturedPan = true;
@@ -449,10 +451,9 @@ export class Gesture {
   componentDidUnload() {
     if (this.blocker) {
       this.blocker.destroy();
-      this.blocker = null;
+      this.blocker = undefined;
     }
-    this.gesture && this.gesture.destroy();
-    this.gesture = this.pan = this.detail = this.detail.event = null;
+    this.gesture.destroy();
   }
 
 }
@@ -462,18 +463,18 @@ const MOUSE_WAIT = 2500;
 
 
 export interface GestureDetail {
-  type?: string;
-  event?: UIEvent;
-  startX?: number;
-  startY?: number;
-  startTimeStamp?: number;
-  currentX?: number;
-  currentY?: number;
-  velocityX?: number;
-  velocityY?: number;
-  deltaX?: number;
-  deltaY?: number;
-  timeStamp?: number;
+  type: string;
+  startX: number;
+  startY: number;
+  startTimeStamp: number;
+  currentX: number;
+  currentY: number;
+  velocityX: number;
+  velocityY: number;
+  deltaX: number;
+  deltaY: number;
+  timeStamp: number;
+  event: UIEvent;
   data?: any;
 }
 
diff --git a/packages/core/src/components/gesture/readme.md b/packages/core/src/components/gesture/readme.md
index f3eddd8e34f..6aa25aa27b5 100644
--- a/packages/core/src/components/gesture/readme.md
+++ b/packages/core/src/components/gesture/readme.md
@@ -17,11 +17,6 @@
 boolean
 
 
-#### block
-
-string
-
-
 #### canStart
 
 
@@ -114,11 +109,6 @@ string
 boolean
 
 
-#### block
-
-string
-
-
 #### can-start
 
 
diff --git a/packages/core/src/components/item-sliding/item-sliding.tsx b/packages/core/src/components/item-sliding/item-sliding.tsx
index b5f4f4e50d3..de0a190900d 100644
--- a/packages/core/src/components/item-sliding/item-sliding.tsx
+++ b/packages/core/src/components/item-sliding/item-sliding.tsx
@@ -34,16 +34,16 @@ export const enum SlidingState {
   }
 })
 export class ItemSliding {
-  private item: HTMLIonItemElement;
-  private list: HTMLIonListElement;
+  private item: HTMLIonItemElement|null;
+  private list: HTMLIonListElement|null;
   private openAmount = 0;
   private initialOpenAmount = 0;
   private optsWidthRightSide = 0;
   private optsWidthLeftSide = 0;
   private sides: ItemSide;
   private tmr: number;
-  private leftOptions: ItemOptions;
-  private rightOptions: ItemOptions;
+  private leftOptions: ItemOptions|null;
+  private rightOptions: ItemOptions|null;
   private optsDirty = true;
 
   @Element() private el: HTMLElement;
@@ -106,7 +106,7 @@ export class ItemSliding {
    */
   @Method()
   closeOpened(): boolean {
-    return this.list && this.list.closeSlidingItems();
+    return !!(this.list && this.list.closeSlidingItems());
   }
 
   private updateOptions() {
diff --git a/packages/core/src/components/list/list.tsx b/packages/core/src/components/list/list.tsx
index 871fdaec9e1..2d5d1a017be 100644
--- a/packages/core/src/components/list/list.tsx
+++ b/packages/core/src/components/list/list.tsx
@@ -14,7 +14,7 @@ import { ItemSliding } from '../item-sliding/item-sliding';
   }
 })
 export class List {
-  private openedItem: ItemSliding;
+  private openedItem: ItemSliding|null;
 
   @Method()
   getOpenedItem() {
@@ -22,7 +22,7 @@ export class List {
   }
 
   @Method()
-  setOpenedItem(itemSliding: ItemSliding) {
+  setOpenedItem(itemSliding: ItemSliding|null) {
     this.openedItem = itemSliding;
   }
 
diff --git a/packages/core/src/components/menu-button/menu-button.tsx b/packages/core/src/components/menu-button/menu-button.tsx
index 85ac6978a78..fb86932c30a 100644
--- a/packages/core/src/components/menu-button/menu-button.tsx
+++ b/packages/core/src/components/menu-button/menu-button.tsx
@@ -1,4 +1,4 @@
-import { Component, Element, Prop, State } from '@stencil/core';
+import { Component, Element, Prop } from '@stencil/core';
 import { Config } from '../../index';
 
 @Component({
@@ -13,14 +13,7 @@ import { Config } from '../../index';
 })
 export class MenuButton {
 
-  @State() custom: boolean;
-
-  /**
-   * The mode determines which platform styles to use.
-   * Possible values are: `"ios"` or `"md"`.
-   * For more information, see [Platform Styles](/docs/theming/platform-specific-styles).
-   */
-  @Prop() mode: 'ios' | 'md';
+  private custom = true;
 
   /**
    * Optional property that maps to a Menu's `menuId` prop. Can also be `left` or `right` for the menu side. This is used to find the correct menu to toggle
@@ -33,34 +26,24 @@ export class MenuButton {
    */
   @Prop() autoHide = true;
 
-
   @Prop({ context: 'config' }) config: Config;
 
   @Element() el: HTMLElement;
 
   componentWillLoad() {
     this.custom = this.el.childElementCount > 0;
-    const closestNav = this.el.closest('ion-nav');
-    closestNav.canGoBack() ? this.el.hidden = true : this.el.hidden = false;
   }
 
   render() {
     const menuIcon = this.config.get('menuIcon', 'menu');
-
-    if (this.custom) {
-      return (
-        <ion-menu-toggle menu={this.menu} autoHide={this.autoHide}>
-          <slot />
-        </ion-menu-toggle>
-      );
-    } else {
-      return (
-        <ion-menu-toggle menu={this.menu} autoHide={this.autoHide}>
-          <ion-button>
-            <ion-icon slot='icon-only' name={menuIcon}></ion-icon>
-          </ion-button>
-        </ion-menu-toggle>
-      );
-    }
+    return (
+      <ion-menu-toggle menu={this.menu} autoHide={this.autoHide}>
+        <ion-button>
+          {this.custom
+            ? <slot/>
+            : <ion-icon slot='icon-only' name={menuIcon}/>}
+        </ion-button>
+      </ion-menu-toggle>
+    );
   }
 }
diff --git a/packages/core/src/components/menu-button/readme.md b/packages/core/src/components/menu-button/readme.md
index 650285a7205..24b1b3c2391 100644
--- a/packages/core/src/components/menu-button/readme.md
+++ b/packages/core/src/components/menu-button/readme.md
@@ -22,15 +22,6 @@ string
 Optional property that maps to a Menu's `menuId` prop. Can also be `left` or `right` for the menu side. This is used to find the correct menu to toggle
 
 
-#### mode
-
-
-
-The mode determines which platform styles to use.
-Possible values are: `"ios"` or `"md"`.
-For more information, see [Platform Styles](/docs/theming/platform-specific-styles).
-
-
 ## Attributes
 
 #### auto-hide
@@ -48,15 +39,6 @@ string
 Optional property that maps to a Menu's `menuId` prop. Can also be `left` or `right` for the menu side. This is used to find the correct menu to toggle
 
 
-#### mode
-
-
-
-The mode determines which platform styles to use.
-Possible values are: `"ios"` or `"md"`.
-For more information, see [Platform Styles](/docs/theming/platform-specific-styles).
-
-
 
 ----------------------------------------------
 
diff --git a/packages/core/src/components/reorder/reorder.tsx b/packages/core/src/components/reorder/reorder.tsx
index bbdd7a79492..95b8406210a 100644
--- a/packages/core/src/components/reorder/reorder.tsx
+++ b/packages/core/src/components/reorder/reorder.tsx
@@ -1,4 +1,4 @@
-import { Component, Element, State } from '@stencil/core';
+import { Component, Element } from '@stencil/core';
 
 
 @Component({
@@ -13,9 +13,9 @@ import { Component, Element, State } from '@stencil/core';
 })
 export class Reorder {
 
-  @Element() private el: HTMLElement;
+  private custom = true;
 
-  @State() custom: boolean;
+  @Element() private el: HTMLElement;
 
   componentWillLoad() {
     this.custom = this.el.childElementCount > 0;
@@ -32,14 +32,9 @@ export class Reorder {
   }
 
   render() {
-    // TODO: https://github.com/ionic-team/stencil/issues/171
-    if (this.custom === true) {
-      return <slot></slot>;
-    } else if (this.custom === false) {
-      return <ion-icon class='reorder-icon' name='reorder'></ion-icon>;
-    } else {
-      return undefined;
-    }
+    return (this.custom)
+      ? <slot/>
+      : <ion-icon class='reorder-icon' name='reorder'/>;
   }
 
 }
diff --git a/packages/core/src/components/scroll/scroll.tsx b/packages/core/src/components/scroll/scroll.tsx
index 53aec612c71..d7b93432fb5 100644
--- a/packages/core/src/components/scroll/scroll.tsx
+++ b/packages/core/src/components/scroll/scroll.tsx
@@ -72,7 +72,8 @@ export class Scroll {
       deltaX: 0,
       deltaY: 0,
       timeStamp: 0,
-      data: undefined
+      data: undefined,
+      isScrolling: true,
     };
   }
 
@@ -317,13 +318,13 @@ function updateScrollDetail(
 }
 
 export interface ScrollDetail extends GestureDetail, ScrollBaseDetail {
-  positions?: number[];
-  scrollTop?: number;
-  scrollLeft?: number;
+  positions: number[];
+  scrollTop: number;
+  scrollLeft: number;
 }
 
 export interface ScrollBaseDetail {
-  isScrolling?: boolean;
+  isScrolling: boolean;
 }
 
 export interface ScrollCallback {
diff --git a/packages/core/src/components/searchbar/searchbar.tsx b/packages/core/src/components/searchbar/searchbar.tsx
index 730b8d0183a..d6531eae48a 100644
--- a/packages/core/src/components/searchbar/searchbar.tsx
+++ b/packages/core/src/components/searchbar/searchbar.tsx
@@ -322,7 +322,7 @@ export class Searchbar {
       this.showCancelButton
         ? <button
           type='button'
-          tabindex={this.mode === 'ios' && !this.activated ? -1 : null}
+          tabindex={this.mode === 'ios' && !this.activated ? -1 : undefined}
           onClick={this.cancelSearchbar.bind(this)}
           onMouseDown={this.cancelSearchbar.bind(this)}
           class={cancelButtonClasses}>
@@ -356,7 +356,7 @@ export class Searchbar {
       </div>
     ];
 
-    if (this.mode === 'ios') {
+    if (cancelButton && this.mode === 'ios') {
       searchbar.push(cancelButton);
     }
 
diff --git a/packages/core/src/components/select-option/readme.md b/packages/core/src/components/select-option/readme.md
index 0f5579938a1..3bfd3c9b6b7 100644
--- a/packages/core/src/components/select-option/readme.md
+++ b/packages/core/src/components/select-option/readme.md
@@ -23,7 +23,7 @@ If true, the element is selected.
 
 #### value
 
-string
+
 
 The text value of the option.
 
@@ -46,7 +46,7 @@ If true, the element is selected.
 
 #### value
 
-string
+
 
 The text value of the option.
 
diff --git a/packages/core/src/components/select-option/select-option.tsx b/packages/core/src/components/select-option/select-option.tsx
index e6e486cc6c8..65bfc58e039 100644
--- a/packages/core/src/components/select-option/select-option.tsx
+++ b/packages/core/src/components/select-option/select-option.tsx
@@ -25,7 +25,7 @@ export class SelectOption {
   /**
    * The text value of the option.
    */
-  @Prop({ mutable: true }) value: string;
+  @Prop({ mutable: true }) value: string|null = null;
 
   /**
    * Emitted when the select option loads.
diff --git a/packages/core/src/components/select/select.tsx b/packages/core/src/components/select/select.tsx
index db21ee60084..97722aabf9a 100644
--- a/packages/core/src/components/select/select.tsx
+++ b/packages/core/src/components/select/select.tsx
@@ -27,7 +27,7 @@ export class Select {
   private childOpts: HTMLIonSelectOptionElement[] = [];
   private selectId: string;
   private labelId: string;
-  private overlay: ActionSheet | Alert | Popover;
+  private overlay: ActionSheet | Alert | Popover | null;
   private styleTmr: any;
   private mode: string;
 
@@ -40,9 +40,7 @@ export class Select {
   @State() text: string;
 
   @Prop({ connect: 'ion-action-sheet-controller' }) actionSheetCtrl: ActionSheetController;
-
   @Prop({ connect: 'ion-alert-controller' }) alertCtrl: AlertController;
-
   @Prop({ connect: 'ion-popover-controller' }) popoverCtrl: PopoverController;
 
   /**
@@ -97,7 +95,7 @@ export class Select {
   /**
    * the value of the select.
    */
-  @Prop({ mutable: true }) value: string | string[];
+  @Prop({ mutable: true }) value: string | string[] | null = null;
 
   /**
    * Emitted when the value has changed.
diff --git a/packages/core/src/components/show-when/show-when.tsx b/packages/core/src/components/show-when/show-when.tsx
index 8fcc3b73f99..c365f453541 100644
--- a/packages/core/src/components/show-when/show-when.tsx
+++ b/packages/core/src/components/show-when/show-when.tsx
@@ -16,11 +16,11 @@ export class ShowWhen implements DisplayWhen {
   @Prop({ context: 'config' }) config: Config;
   @Prop({ context: 'platforms' }) calculatedPlatforms: PlatformConfig[];
 
-  @Prop() orientation: string = null;
-  @Prop() mediaQuery: string = null;
-  @Prop() size: string = null;
-  @Prop() mode: string = null;
-  @Prop() platform: string = null;
+  @Prop() orientation: string;
+  @Prop() mediaQuery: string;
+  @Prop() size: string;
+  @Prop() mode: string;
+  @Prop() platform: string;
   @Prop() or = false;
 
   @State() passesTest = false;
diff --git a/packages/core/src/index.d.ts b/packages/core/src/index.d.ts
index 655f6f5caeb..488e1d9ab55 100644
--- a/packages/core/src/index.d.ts
+++ b/packages/core/src/index.d.ts
@@ -33,6 +33,7 @@ export { FabButton } from './components/fab-button/fab-button';
 export { Footer } from './components/footer/footer';
 export { Gesture, GestureCallback, GestureDetail } from './components/gesture/gesture';
 export { PanRecognizer } from './components/gesture/recognizers';
+export { GestureController } from './components/gesture-controller/gesture-controller';
 export * from './components/gesture-controller/gesture-controller-utils';
 export { Grid } from './components/grid/grid';
 export { Header } from './components/header/header';
diff --git a/packages/core/src/utils/helpers.ts b/packages/core/src/utils/helpers.ts
index ec2704abe2f..8cc49c51a89 100644
--- a/packages/core/src/utils/helpers.ts
+++ b/packages/core/src/utils/helpers.ts
@@ -53,7 +53,7 @@ export function assert(actual: any, reason: string) {
   }
 }
 
-export function autoFocus(containerEl: HTMLElement): HTMLElement {
+export function autoFocus(containerEl: HTMLElement): HTMLElement|null {
   const focusableEls = containerEl.querySelectorAll('a[href], area[href], input:not([disabled]), select:not([disabled]), textarea:not([disabled]), button:not([disabled]), [tabindex="0"]');
   if (focusableEls.length > 0) {
     const el = focusableEls[0] as HTMLInputElement;
@@ -335,7 +335,7 @@ export function isParentTab(element: HTMLElement) {
   return element.parentElement.tagName.toLowerCase() === 'ion-tab';
 }
 
-export function getIonApp(): Promise<HTMLIonAppElement> {
+export function getIonApp(): Promise<HTMLIonAppElement|null> {
   const appElement = document.querySelector('ion-app');
   if (!appElement) {
     return Promise.resolve(null);
diff --git a/packages/core/src/utils/overlays.ts b/packages/core/src/utils/overlays.ts
index d73372e6e1d..3c1765beeaa 100644
--- a/packages/core/src/utils/overlays.ts
+++ b/packages/core/src/utils/overlays.ts
@@ -30,7 +30,7 @@ export function createOverlay
   return element.componentOnReady();
 }
 
-export function dismissOverlay(data: any, role: string, overlays: OverlayMap, id: number): Promise<void> {
+export function dismissOverlay(data: any, role: string|undefined, overlays: OverlayMap, id: number): Promise<void> {
   id = id >= 0 ? id : getHighestId(overlays);
   const overlay = overlays.get(id);
   if (!overlay) {
@@ -67,7 +67,7 @@ export function overlayAnimation(
 ): Promise<void> {
   if (overlay.animation) {
     overlay.animation.destroy();
-    overlay.animation = null;
+    overlay.animation = undefined;
   }
   return overlay.animationCtrl.create(animationBuilder, baseEl, opts).then(animation => {
     overlay.animation = animation;
@@ -77,13 +77,13 @@ export function overlayAnimation(
     return playAnimationAsync(animation);
   }).then((animation) => {
     animation.destroy();
-    overlay.animation = null;
+    overlay.animation = undefined;
   });
 }
 
 export interface OverlayInterface {
   overlayId: number;
-  animation: Animation;
+  animation: Animation|undefined;
   animationCtrl: HTMLIonAnimationControllerElement;
 
   present(): Promise<void>;
diff --git a/packages/core/src/utils/show-hide-when-utils.ts b/packages/core/src/utils/show-hide-when-utils.ts
index 9681b3e8f6c..fb51036461e 100644
--- a/packages/core/src/utils/show-hide-when-utils.ts
+++ b/packages/core/src/utils/show-hide-when-utils.ts
@@ -19,12 +19,8 @@ export function isPlatformMatch(platforms: string[], multiPlatformString: string
 export function isModeMatch(config: Config, multiModeString: string) {
   // you can only ever be in one mode, so if an entry from the list matches, return true
   const modes = multiModeString.replace(/\s/g, '').split(',');
-  for (const mode of modes) {
-    if (config.get('mode') === mode) {
-      return true;
-    }
-  }
-  return false;
+  const currentMode = config.get('mode');
+  return modes.indexOf(currentMode) >= 0;
 }
 
 
@@ -34,16 +30,13 @@ export function isMediaQueryMatch(mediaQuery: string) {
 
 export function isSizeMatch(multiSizeString: string) {
   const sizes = multiSizeString.replace(/\s/g, '').split(',');
-
-  const booleans = sizes.map(size => {
-    const mediaQuery = sizeToMediaQueryMap.get(size);
-    if (!mediaQuery) {
-      return false;
+  for (const size of sizes) {
+    const mediaQuery = SIZE_TO_MEDIA[size];
+    if (mediaQuery && window.matchMedia(mediaQuery).matches) {
+      return true;
     }
-
-    return window.matchMedia(mediaQuery).matches;
-  });
-  return booleans.reduce((prev, current) => prev || current);
+  }
+  return false;
 }
 
 export function getTestResult(displayWhen: DisplayWhen) {
@@ -93,12 +86,13 @@ export function isPortrait(): boolean {
   return window.matchMedia('(orientation: portrait)').matches;
 }
 
-const sizeToMediaQueryMap = new Map<string, string>();
-sizeToMediaQueryMap.set('xs', '(min-width: 0px)');
-sizeToMediaQueryMap.set('sm', '(min-width: 576px)');
-sizeToMediaQueryMap.set('md', '(min-width: 768px)');
-sizeToMediaQueryMap.set('lg', '(min-width: 992px)');
-sizeToMediaQueryMap.set('xl', '(min-width: 1200px)');
+const SIZE_TO_MEDIA: any = {
+  'xs': '(min-width: 0px)',
+  'sm': '(min-width: 576px)',
+  'md': '(min-width: 768px)',
+  'lg': '(min-width: 992px)',
+  'xl': '(min-width: 1200px)'
+};
 
 export interface DisplayWhen {
   calculatedPlatforms: PlatformConfig[];
diff --git a/packages/core/tsconfig.json b/packages/core/tsconfig.json
index c76004214c6..377d6917ac3 100644
--- a/packages/core/tsconfig.json
+++ b/packages/core/tsconfig.json
@@ -1,6 +1,7 @@
 {
   "compilerOptions": {
     "alwaysStrict": true,
+    "strictPropertyInitialization": false,
     "allowSyntheticDefaultImports": true,
     "allowUnreachableCode": false,
     "declaration": true,