Panel, Modal, Overlay: Optional prop that disables bodyscroll block on touch devices

change/@uifabric-utilities-2019-11-28-22-34-32-master.json

@@ -0,0 +1,8 @@
+{
+  "type": "minor",
+  "comment": "scroll.ts: extended event handler provided by _makeElementScrollAllower with allowIosOverscroll argument to make blocking of body scroll on touch devices optional",
+  "packageName": "@uifabric/utilities",
+  "email": "dmitriy.ravdin@siemens.com",
+  "commit": "00c16da9f0d9ee3de29c6de6a0aa32d50397cdcc",
+  "date": "2019-11-28T21:34:32.268Z"
+}

change/office-ui-fabric-react-2019-11-28-22-34-32-master.json

@@ -0,0 +1,8 @@
+{
+  "type": "minor",
+  "comment": "modal, panel, overlay components: added optional prop allowIosBodyScroll to allow body scroll on touch devices",
+  "packageName": "office-ui-fabric-react",
+  "email": "dmitriy.ravdin@siemens.com",
+  "commit": "00c16da9f0d9ee3de29c6de6a0aa32d50397cdcc",
+  "date": "2019-11-28T21:34:30.900Z"
+}

packages/office-ui-fabric-react/etc/office-ui-fabric-react.api.md

@@ -5531,6 +5531,7 @@ export interface IModal {
 
 // @public (undocumented)
 export interface IModalProps extends React.ClassAttributes<ModalBase>, IWithResponsiveModeState, IAccessiblePopupProps {
+    allowTouchBodyScroll?: boolean;
     className?: string;
     componentRef?: IRefObject<IModal>;
     containerClassName?: string;
@@ -5739,6 +5740,7 @@ export interface IOverlay {
 
 // @public (undocumented)
 export interface IOverlayProps extends React.HTMLAttributes<HTMLElement> {
+    allowTouchBodyScroll?: boolean;
     className?: string;
     componentRef?: IRefObject<IOverlay>;
     isDarkThemed?: boolean;
@@ -5818,6 +5820,7 @@ export interface IPanelHeaderRenderer extends IRenderFunction<IPanelProps> {
 // 
 // @public (undocumented)
 export interface IPanelProps extends React.HTMLAttributes<PanelBase> {
+    allowTouchBodyScroll?: boolean;
     className?: string;
     closeButtonAriaLabel?: string;
     // @deprecated
@@ -8217,6 +8220,7 @@ export const Overlay: React.StatelessComponent<IOverlayProps>;
 
 // @public (undocumented)
 export class OverlayBase extends BaseComponent<IOverlayProps, {}> {
+    constructor(props: IOverlayProps);
     // (undocumented)
     componentDidMount(): void;
     // (undocumented)

packages/office-ui-fabric-react/src/components/Modal/Modal.base.tsx

@@ -1,5 +1,13 @@
 import * as React from 'react';
-import { BaseComponent, classNamesFunction, getId, allowScrollOnElement, KeyCodes, elementContains } from '../../Utilities';
+import {
+  BaseComponent,
+  classNamesFunction,
+  getId,
+  allowScrollOnElement,
+  allowOverscrollOnElement,
+  KeyCodes,
+  elementContains
+} from '../../Utilities';
 import { FocusTrapZone, IFocusTrapZone } from '../FocusTrapZone/index';
 import { animationDuration } from './Modal.styles';
 import { IModalProps, IModalStyleProps, IModalStyles, IModal } from './Modal.types';
@@ -47,6 +55,7 @@ export class ModalBase extends BaseComponent<IModalProps, IDialogState> implemen
   private _scrollableContent: HTMLDivElement | null;
   private _lastSetX: number;
   private _lastSetY: number;
+  private _allowTouchBodyScroll: boolean;
   private _hasRegisteredKeyUp: boolean;
 
   constructor(props: IModalProps) {
@@ -66,6 +75,9 @@ export class ModalBase extends BaseComponent<IModalProps, IDialogState> implemen
     this._warnDeprecations({
       onLayerDidMount: 'layerProps.onLayerDidMount'
     });
+
+    const { allowTouchBodyScroll = false } = this.props;
+    this._allowTouchBodyScroll = allowTouchBodyScroll;
   }
 
   // tslint:disable-next-line function-name
@@ -238,7 +250,14 @@ export class ModalBase extends BaseComponent<IModalProps, IDialogState> implemen
             onDismiss={onDismiss}
           >
             <div className={classNames.root}>
-              {!isModeless && <Overlay isDarkThemed={isDarkOverlay} onClick={isBlocking ? undefined : (onDismiss as any)} {...overlay} />}
+              {!isModeless && (
+                <Overlay
+                  isDarkThemed={isDarkOverlay}
+                  onClick={isBlocking ? undefined : (onDismiss as any)}
+                  allowTouchBodyScroll={this._allowTouchBodyScroll}
+                  {...overlay}
+                />
+              )}
               {dragOptions ? (
                 <DraggableZone
                   handleSelector={dragOptions.dragHandleSelector || `.${classNames.main.split(' ')[0]}`}
@@ -270,7 +289,11 @@ export class ModalBase extends BaseComponent<IModalProps, IDialogState> implemen
   // Allow the user to scroll within the modal but not on the body
   private _allowScrollOnModal = (elt: HTMLDivElement | null): void => {
     if (elt) {
-      allowScrollOnElement(elt, this._events);
+      if (this._allowTouchBodyScroll) {
+        allowOverscrollOnElement(elt, this._events);
+      } else {
+        allowScrollOnElement(elt, this._events);
+      }
     } else {
       this._events.off(this._scrollableContent);
     }

packages/office-ui-fabric-react/src/components/Modal/Modal.types.ts

@@ -153,6 +153,12 @@ export interface IModalProps extends React.ClassAttributes<ModalBase>, IWithResp
    * The options to make the modal draggable
    */
   dragOptions?: IDragOptions;
+
+  /**
+   * Allow body scroll on content and overlay. Changing after mounting has no effect.
+   * @defaultvalue false
+   */
+  allowTouchBodyScroll?: boolean;
 }
 
 /**

packages/office-ui-fabric-react/src/components/Overlay/Overlay.base.tsx

@@ -5,12 +5,21 @@ import { IOverlayProps, IOverlayStyleProps, IOverlayStyles } from './Overlay.typ
 const getClassNames = classNamesFunction<IOverlayStyleProps, IOverlayStyles>();
 
 export class OverlayBase extends BaseComponent<IOverlayProps, {}> {
+  private _allowTouchBodyScroll: boolean;
+
+  constructor(props: IOverlayProps) {
+    super(props);
+
+    const { allowTouchBodyScroll = false } = this.props;
+    this._allowTouchBodyScroll = allowTouchBodyScroll;
+  }
+
   public componentDidMount(): void {
-    disableBodyScroll();
+    !this._allowTouchBodyScroll && disableBodyScroll();
   }
 
   public componentWillUnmount(): void {
-    enableBodyScroll();
+    !this._allowTouchBodyScroll && enableBodyScroll();
   }
 
   public render(): JSX.Element {

packages/office-ui-fabric-react/src/components/Overlay/Overlay.types.ts

@@ -39,6 +39,12 @@ export interface IOverlayProps extends React.HTMLAttributes<HTMLElement> {
   isDarkThemed?: boolean;
 
   onClick?: () => void;
+
+  /**
+   * Allow body scroll on ios. Changing after mounting has no effect.
+   * @defaultvalue false
+   */
+  allowTouchBodyScroll?: boolean;
 }
 
 /**

packages/office-ui-fabric-react/src/components/Panel/Panel.base.tsx

@@ -6,6 +6,7 @@ import { Popup } from '../../Popup';
 import { getTheme, IconFontSizes, IProcessedStyleSet } from '../../Styling';
 import {
   allowScrollOnElement,
+  allowOverscrollOnElement,
   BaseComponent,
   classNamesFunction,
   divProperties,
@@ -45,6 +46,7 @@ export class PanelBase extends BaseComponent<IPanelProps, IPanelState> implement
   private _classNames: IProcessedStyleSet<IPanelStyles>;
   private _scrollableContent: HTMLDivElement | null;
   private _animationCallback: number | null = null;
+  private _allowTouchBodyScroll: boolean;
 
   public static getDerivedStateFromProps(nextProps: Readonly<IPanelProps>, prevState: Readonly<IPanelState>): Partial<IPanelState> | null {
     if (nextProps.isOpen === undefined) {
@@ -68,6 +70,9 @@ export class PanelBase extends BaseComponent<IPanelProps, IPanelState> implement
   constructor(props: IPanelProps) {
     super(props);
 
+    const { allowTouchBodyScroll = false } = this.props;
+    this._allowTouchBodyScroll = allowTouchBodyScroll;
+
     this._warnDeprecations({
       ignoreExternalFocusing: 'focusTrapZoneProps',
       forceFocusInsideTrap: 'focusTrapZoneProps',
@@ -169,7 +174,7 @@ export class PanelBase extends BaseComponent<IPanelProps, IPanelState> implement
       type
     });
 
-    const { _classNames } = this;
+    const { _classNames, _allowTouchBodyScroll } = this;
 
     let overlay;
     if (isBlocking && isOpen) {
@@ -178,6 +183,7 @@ export class PanelBase extends BaseComponent<IPanelProps, IPanelState> implement
           className={_classNames.overlay}
           isDarkThemed={false}
           onClick={isLightDismiss ? onLightDismissClick : undefined}
+          allowTouchBodyScroll={_allowTouchBodyScroll}
           {...overlayProps}
         />
       );
@@ -268,7 +274,11 @@ export class PanelBase extends BaseComponent<IPanelProps, IPanelState> implement
   // Allow the user to scroll within the panel but not on the body
   private _allowScrollOnPanel = (elt: HTMLDivElement | null): void => {
     if (elt) {
-      allowScrollOnElement(elt, this._events);
+      if (this._allowTouchBodyScroll) {
+        allowOverscrollOnElement(elt, this._events);
+      } else {
+        allowScrollOnElement(elt, this._events);
+      }
     } else {
       this._events.off(this._scrollableContent);
     }

packages/office-ui-fabric-react/src/components/Panel/Panel.types.ts

@@ -225,6 +225,12 @@ export interface IPanelProps extends React.HTMLAttributes<PanelBase> {
    * @deprecated Serves no function.
    */
   componentId?: string;
+
+  /**
+   * Allow body scroll on content and overlay. Changing after mounting has no effect.
+   * @defaultvalue false
+   */
+  allowTouchBodyScroll?: boolean;
 }
 
 /**

packages/utilities/etc/utilities.api.md

@@ -17,6 +17,9 @@ export function addDirectionalKeyCode(which: number): void;
 // @public
 export function addElementAtIndex<T>(array: T[], index: number, itemToAdd: T): T[];
 
+// @public
+export const allowOverscrollOnElement: (element: HTMLElement | null, events: EventGroup) => void;
+
 // @public
 export const allowScrollOnElement: (element: HTMLElement | null, events: EventGroup) => void;
 

packages/utilities/src/scroll.ts

@@ -84,6 +84,19 @@ const _makeElementScrollAllower = () => {
  */
 export const allowScrollOnElement = _makeElementScrollAllower();
 
+/**
+ * Same as allowScrollOnElement but does not prevent overscrolling.
+ */
+export const allowOverscrollOnElement = (element: HTMLElement | null, events: EventGroup): void => {
+  if (!element) {
+    return;
+  }
+  const _allowElementScroll = (event: TouchEvent) => {
+    event.stopPropagation();
+  };
+  events.on(element, 'touchmove', _allowElementScroll, { passive: false });
+};
+
 const _disableIosBodyScroll = (event: TouchEvent) => {
   event.preventDefault();
 };