text: import { CdkAccordionItem, CdkAccordion, CdkAccordionModule } from '@angular/cdk/accordion';
  import { TemplatePortal, PortalModule } from '@angular/cdk/portal';
  import { DOCUMENT, CommonModule } from '@angular/common';
  import { InjectionToken, Directive, TemplateRef, EventEmitter, Component, ViewEncapsulation, ChangeDetectionStrategy, Optional, SkipSelf, Inject, ChangeDetectorRef, ViewContainerRef, Input, Output, ContentChild, ViewChild, Host, ElementRef, Attribute, QueryList, ContentChildren, NgModule } from '@angular/core';
  import { mixinTabIndex, MatCommonModule } from '@angular/material/core';
  import { coerceBooleanProperty } from '@angular/cdk/coercion';
  import { FocusMonitor, FocusKeyManager } from '@angular/cdk/a11y';
  import { distinctUntilChanged, startWith, filter, take } from 'rxjs/operators';
  import { ENTER, hasModifierKey, SPACE } from '@angular/cdk/keycodes';
  import { ANIMATION_MODULE_TYPE } from '@angular/platform-browser/animations';
  import { Subject, Subscription, EMPTY, merge } from 'rxjs';
  import { trigger, state, style, transition, animate } from '@angular/animations';
  import { UniqueSelectionDispatcher } from '@angular/cdk/collections';
  
  /**
   * @license
   * Copyright Google LLC All Rights Reserved.
   *
   * Use of this source code is governed by an MIT-style license that can be
   * found in the LICENSE file at https://angular.io/license
   */
  /**
   * Token used to provide a `MatAccordion` to `MatExpansionPanel`.
   * Used primarily to avoid circular imports between `MatAccordion` and `MatExpansionPanel`.
   */
  const MAT_ACCORDION = new InjectionToken('MAT_ACCORDION');
  
  /**
   * @license
   * Copyright Google LLC All Rights Reserved.
   *
   * Use of this source code is governed by an MIT-style license that can be
   * found in the LICENSE file at https://angular.io/license
   */
  /** Time and timing curve for expansion panel animations. */
  // Note: Keep this in sync with the Sass variable for the panel header animation.
  const EXPANSION_PANEL_ANIMATION_TIMING = '225ms cubic-bezier(0.4,0.0,0.2,1)';
  /**
   * Animations used by the Material expansion panel.
   *
   * A bug in angular animation's `state` when ViewContainers are moved using ViewContainerRef.move()
   * causes the animation state of moved components to become `void` upon exit, and not update again
   * upon reentry into the DOM.  This can lead a to situation for the expansion panel where the state
   * of the panel is `expanded` or `collapsed` but the animation state is `void`.
   *
   * To correctly handle animating to the next state, we animate between `void` and `collapsed` which
   * are defined to have the same styles. Since angular animates from the current styles to the
   * destination state's style definition, in situations where we are moving from `void`'s styles to
   * `collapsed` this acts a noop since no style values change.
   *
   * In the case where angular's animation state is out of sync with the expansion panel's state, the
   * expansion panel being `expanded` and angular animations being `void`, the animation from the
   * `expanded`'s effective styles (though in a `void` animation state) to the collapsed state will
   * occur as expected.
   *
   * Angular Bug: https://github.com/angular/angular/issues/18847
   *
   * @docs-private
   */
  const matExpansionAnimations = {
      /** Animation that rotates the indicator arrow. */
      indicatorRotate: trigger('indicatorRotate', [
          state('collapsed, void', style({ transform: 'rotate(0deg)' })),
          state('expanded', style({ transform: 'rotate(180deg)' })),
          transition('expanded <=> collapsed, void => collapsed', animate(EXPANSION_PANEL_ANIMATION_TIMING)),
      ]),
      /** Animation that expands and collapses the panel content. */
      bodyExpansion: trigger('bodyExpansion', [
          state('collapsed, void', style({ height: '0px', visibility: 'hidden' })),
          state('expanded', style({ height: '*', visibility: 'visible' })),
          transition('expanded <=> collapsed, void => collapsed', animate(EXPANSION_PANEL_ANIMATION_TIMING)),
      ])
  };
  
  /**
   * @license
   * Copyright Google LLC All Rights Reserved.
   *
   * Use of this source code is governed by an MIT-style license that can be
   * found in the LICENSE file at https://angular.io/license
   */
  /**
   * Expansion panel content that will be rendered lazily
   * after the panel is opened for the first time.
   */
  class MatExpansionPanelContent {
      constructor(_template) {
          this._template = _template;
      }
  }
  MatExpansionPanelContent.decorators = [
      { type: Directive, args: [{
                  selector: 'ng-template[matExpansionPanelContent]'
              },] }
  ];
  MatExpansionPanelContent.ctorParameters = () => [
      { type: TemplateRef }
  ];
  
  /**
   * @license
   * Copyright Google LLC All Rights Reserved.
   *
   * Use of this source code is governed by an MIT-style license that can be
   * found in the LICENSE file at https://angular.io/license
   */
  /** Counter for generating unique element ids. */
  let uniqueId = 0;
  /**
   * Injection token that can be used to configure the default
   * options for the expansion panel component.
   */
  const MAT_EXPANSION_PANEL_DEFAULT_OPTIONS = new InjectionToken('MAT_EXPANSION_PANEL_DEFAULT_OPTIONS');
  const ɵ0 = undefined;
  /**
   * This component can be used as a single element to show expandable content, or as one of
   * multiple children of an element with the MatAccordion directive attached.
   */
  class MatExpansionPanel extends CdkAccordionItem {
      constructor(accordion, _changeDetectorRef, _uniqueSelectionDispatcher, _viewContainerRef, _document, _animationMode, defaultOptions) {
          super(accordion, _changeDetectorRef, _uniqueSelectionDispatcher);
          this._viewContainerRef = _viewContainerRef;
          this._animationMode = _animationMode;
          this._hideToggle = false;
          /** An event emitted after the body's expansion animation happens. */
          this.afterExpand = new EventEmitter();
          /** An event emitted after the body's collapse animation happens. */
          this.afterCollapse = new EventEmitter();
          /** Stream that emits for changes in `@Input` properties. */
          this._inputChanges = new Subject();
          /** ID for the associated header element. Used for a11y labelling. */
          this._headerId = `mat-expansion-panel-header-${uniqueId++}`;
          /** Stream of body animation done events. */
          this._bodyAnimationDone = new Subject();
          this.accordion = accordion;
          this._document = _document;
          // We need a Subject with distinctUntilChanged, because the `done` event
          // fires twice on some browsers. See https://github.com/angular/angular/issues/24084
          this._bodyAnimationDone.pipe(distinctUntilChanged((x, y) => {
              return x.fromState === y.fromState && x.toState === y.toState;
          })).subscribe(event => {
              if (event.fromState !== 'void') {
                  if (event.toState === 'expanded') {
                      this.afterExpand.emit();
                  }
                  else if (event.toState === 'collapsed') {
                      this.afterCollapse.emit();
                  }
              }
          });
          if (defaultOptions) {
              this.hideToggle = defaultOptions.hideToggle;
          }
      }
      /** Whether the toggle indicator should be hidden. */
      get hideToggle() {
          return this._hideToggle || (this.accordion && this.accordion.hideToggle);
      }
      set hideToggle(value) {
          this._hideToggle = coerceBooleanProperty(value);
      }
      /** The position of the expansion indicator. */
      get togglePosition() {
          return this._togglePosition || (this.accordion && this.accordion.togglePosition);
      }
      set togglePosition(value) {
          this._togglePosition = value;
      }
      /** Determines whether the expansion panel should have spacing between it and its siblings. */
      _hasSpacing() {
          if (this.accordion) {
              return this.expanded && this.accordion.displayMode === 'default';
          }
          return false;
      }
      /** Gets the expanded state string. */
      _getExpandedState() {
          return this.expanded ? 'expanded' : 'collapsed';
      }
      /** Toggles the expanded state of the expansion panel. */
      toggle() {
          this.expanded = !this.expanded;
      }
      /** Sets the expanded state of the expansion panel to false. */
      close() {
          this.expanded = false;
      }
      /** Sets the expanded state of the expansion panel to true. */
      open() {
          this.expanded = true;
      }
      ngAfterContentInit() {
          if (this._lazyContent) {
              // Render the content as soon as the panel becomes open.
              this.opened.pipe(startWith(null), filter(() => this.expanded && !this._portal), take(1)).subscribe(() => {
                  this._portal = new TemplatePortal(this._lazyContent._template, this._viewContainerRef);
              });
          }
      }
      ngOnChanges(changes) {
          this._inputChanges.next(changes);
      }
      ngOnDestroy() {
          super.ngOnDestroy();
          this._bodyAnimationDone.complete();
          this._inputChanges.complete();
      }
      /** Checks whether the expansion panel's content contains the currently-focused element. */
      _containsFocus() {
          if (this._body) {
              const focusedElement = this._document.activeElement;
              const bodyElement = this._body.nativeElement;
              return focusedElement === bodyElement || bodyElement.contains(focusedElement);
          }
          return false;
      }
  }
  MatExpansionPanel.decorators = [
      { type: Component, args: [{
                  selector: 'mat-expansion-panel',
                  exportAs: 'matExpansionPanel',
                  template: "<ng-content select=\"mat-expansion-panel-header\"></ng-content>\n<div class=\"mat-expansion-panel-content\"\n     role=\"region\"\n     [@bodyExpansion]=\"_getExpandedState()\"\n     (@bodyExpansion.done)=\"_bodyAnimationDone.next($event)\"\n     [attr.aria-labelledby]=\"_headerId\"\n     [id]=\"id\"\n     #body>\n  <div class=\"mat-expansion-panel-body\">\n    <ng-content></ng-content>\n    <ng-template [cdkPortalOutlet]=\"_portal\"></ng-template>\n  </div>\n  <ng-content select=\"mat-action-row\"></ng-content>\n</div>\n",
                  encapsulation: ViewEncapsulation.None,
                  changeDetection: ChangeDetectionStrategy.OnPush,
                  inputs: ['disabled', 'expanded'],
                  outputs: ['opened', 'closed', 'expandedChange'],
                  animations: [matExpansionAnimations.bodyExpansion],
                  providers: [
                      // Provide MatAccordion as undefined to prevent nested expansion panels from registering
                      // to the same accordion.
                      { provide: MAT_ACCORDION, useValue: ɵ0 },
                  ],
                  host: {
                      'class': 'mat-expansion-panel',
                      '[class.mat-expanded]': 'expanded',
                      '[class._mat-animation-noopable]': '_animationMode === "NoopAnimations"',
                      '[class.mat-expansion-panel-spacing]': '_hasSpacing()',
                  },
                  styles: [".mat-expansion-panel{box-sizing:content-box;display:block;margin:0;border-radius:4px;overflow:hidden;transition:margin 225ms cubic-bezier(0.4, 0, 0.2, 1),box-shadow 280ms cubic-bezier(0.4, 0, 0.2, 1);position:relative}.mat-accordion .mat-expansion-panel:not(.mat-expanded),.mat-accordion .mat-expansion-panel:not(.mat-expansion-panel-spacing){border-radius:0}.mat-accordion .mat-expansion-panel:first-of-type{border-top-right-radius:4px;border-top-left-radius:4px}.mat-accordion .mat-expansion-panel:last-of-type{border-bottom-right-radius:4px;border-bottom-left-radius:4px}.cdk-high-contrast-active .mat-expansion-panel{outline:solid 1px}.mat-expansion-panel.ng-animate-disabled,.ng-animate-disabled .mat-expansion-panel,.mat-expansion-panel._mat-animation-noopable{transition:none}.mat-expansion-panel-content{display:flex;flex-direction:column;overflow:visible}.mat-expansion-panel-body{padding:0 24px 16px}.mat-expansion-panel-spacing{margin:16px 0}.mat-accordion>.mat-expansion-panel-spacing:first-child,.mat-accordion>*:first-child:not(.mat-expansion-panel) .mat-expansion-panel-spacing{margin-top:0}.mat-accordion>.mat-expansion-panel-spacing:last-child,.mat-accordion>*:last-child:not(.mat-expansion-panel) .mat-expansion-panel-spacing{margin-bottom:0}.mat-action-row{border-top-style:solid;border-top-width:1px;display:flex;flex-direction:row;justify-content:flex-end;padding:16px 8px 16px 24px}.mat-action-row button.mat-button-base,.mat-action-row button.mat-mdc-button-base{margin-left:8px}[dir=rtl] .mat-action-row button.mat-button-base,[dir=rtl] .mat-action-row button.mat-mdc-button-base{margin-left:0;margin-right:8px}\n"]
              },] }
  ];
  MatExpansionPanel.ctorParameters = () => [
      { type: undefined, decorators: [{ type: Optional }, { type: SkipSelf }, { type: Inject, args: [MAT_ACCORDION,] }] },
      { type: ChangeDetectorRef },
      { type: UniqueSelectionDispatcher },
      { type: ViewContainerRef },
      { type: undefined, decorators: [{ type: Inject, args: [DOCUMENT,] }] },
      { type: String, decorators: [{ type: Optional }, { type: Inject, args: [ANIMATION_MODULE_TYPE,] }] },
      { type: undefined, decorators: [{ type: Inject, args: [MAT_EXPANSION_PANEL_DEFAULT_OPTIONS,] }, { type: Optional }] }
  ];
  MatExpansionPanel.propDecorators = {
      hideToggle: [{ type: Input }],
      togglePosition: [{ type: Input }],
      afterExpand: [{ type: Output }],
      afterCollapse: [{ type: Output }],
      _lazyContent: [{ type: ContentChild, args: [MatExpansionPanelContent,] }],
      _body: [{ type: ViewChild, args: ['body',] }]
  };
  /**
   * Actions of a `<mat-expansion-panel>`.
   */
  class MatExpansionPanelActionRow {
  }
  MatExpansionPanelActionRow.decorators = [
      { type: Directive, args: [{
                  selector: 'mat-action-row',
                  host: {
                      class: 'mat-action-row'
                  }
              },] }
  ];
  
  /**
   * @license
   * Copyright Google LLC All Rights Reserved.
   *
   * Use of this source code is governed by an MIT-style license that can be
   * found in the LICENSE file at https://angular.io/license
   */
  // Boilerplate for applying mixins to MatExpansionPanelHeader.
  /** @docs-private */
  class MatExpansionPanelHeaderBase {
  }
  const _MatExpansionPanelHeaderMixinBase = mixinTabIndex(MatExpansionPanelHeaderBase);
  /**
   * Header element of a `<mat-expansion-panel>`.
   */
  class MatExpansionPanelHeader extends _MatExpansionPanelHeaderMixinBase {
      constructor(panel, _element, _focusMonitor, _changeDetectorRef, defaultOptions, _animationMode, tabIndex) {
          super();
          this.panel = panel;
          this._element = _element;
          this._focusMonitor = _focusMonitor;
          this._changeDetectorRef = _changeDetectorRef;
          this._animationMode = _animationMode;
          this._parentChangeSubscription = Subscription.EMPTY;
          const accordionHideToggleChange = panel.accordion ?
              panel.accordion._stateChanges.pipe(filter(changes => !!(changes['hideToggle'] || changes['togglePosition']))) :
              EMPTY;
          this.tabIndex = parseInt(tabIndex || '') || 0;
          // Since the toggle state depends on an @Input on the panel, we
          // need to subscribe and trigger change detection manually.
          this._parentChangeSubscription =
              merge(panel.opened, panel.closed, accordionHideToggleChange, panel._inputChanges.pipe(filter(changes => {
                  return !!(changes['hideToggle'] ||
                      changes['disabled'] ||
                      changes['togglePosition']);
              })))
                  .subscribe(() => this._changeDetectorRef.markForCheck());
          // Avoids focus being lost if the panel contained the focused element and was closed.
          panel.closed
              .pipe(filter(() => panel._containsFocus()))
              .subscribe(() => _focusMonitor.focusVia(_element, 'program'));
          if (defaultOptions) {
              this.expandedHeight = defaultOptions.expandedHeight;
              this.collapsedHeight = defaultOptions.collapsedHeight;
          }
      }
      /**
       * Whether the associated panel is disabled. Implemented as a part of `FocusableOption`.
       * @docs-private
       */
      get disabled() {
          return this.panel.disabled;
      }
      /** Toggles the expanded state of the panel. */
      _toggle() {
          if (!this.disabled) {
              this.panel.toggle();
          }
      }
      /** Gets whether the panel is expanded. */
      _isExpanded() {
          return this.panel.expanded;
      }
      /** Gets the expanded state string of the panel. */
      _getExpandedState() {
          return this.panel._getExpandedState();
      }
      /** Gets the panel id. */
      _getPanelId() {
          return this.panel.id;
      }
      /** Gets the toggle position for the header. */
      _getTogglePosition() {
          return this.panel.togglePosition;
      }
      /** Gets whether the expand indicator should be shown. */
      _showToggle() {
          return !this.panel.hideToggle && !this.panel.disabled;
      }
      /**
       * Gets the current height of the header. Null if no custom height has been
       * specified, and if the default height from the stylesheet should be used.
       */
      _getHeaderHeight() {
          const isExpanded = this._isExpanded();
          if (isExpanded && this.expandedHeight) {
              return this.expandedHeight;
          }
          else if (!isExpanded && this.collapsedHeight) {
              return this.collapsedHeight;
          }
          return null;
      }
      /** Handle keydown event calling to toggle() if appropriate. */
      _keydown(event) {
          switch (event.keyCode) {
              // Toggle for space and enter keys.
              case SPACE:
              case ENTER:
                  if (!hasModifierKey(event)) {
                      event.preventDefault();
                      this._toggle();
                  }
                  break;
              default:
                  if (this.panel.accordion) {
                      this.panel.accordion._handleHeaderKeydown(event);
                  }
                  return;
          }
      }
      /**
       * Focuses the panel header. Implemented as a part of `FocusableOption`.
       * @param origin Origin of the action that triggered the focus.
       * @docs-private
       */
      focus(origin, options) {
          if (origin) {
              this._focusMonitor.focusVia(this._element, origin, options);
          }
          else {
              this._element.nativeElement.focus(options);
          }
      }
      ngAfterViewInit() {
          this._focusMonitor.monitor(this._element).subscribe(origin => {
              if (origin && this.panel.accordion) {
                  this.panel.accordion._handleHeaderFocus(this);
              }
          });
      }
      ngOnDestroy() {
          this._parentChangeSubscription.unsubscribe();
          this._focusMonitor.stopMonitoring(this._element);
      }
  }
  MatExpansionPanelHeader.decorators = [
      { type: Component, args: [{
                  selector: 'mat-expansion-panel-header',
                  template: "<span class=\"mat-content\">\n  <ng-content select=\"mat-panel-title\"></ng-content>\n  <ng-content select=\"mat-panel-description\"></ng-content>\n  <ng-content></ng-content>\n</span>\n<span [@indicatorRotate]=\"_getExpandedState()\" *ngIf=\"_showToggle()\"\n      class=\"mat-expansion-indicator\"></span>\n",
                  encapsulation: ViewEncapsulation.None,
                  changeDetection: ChangeDetectionStrategy.OnPush,
                  inputs: ['tabIndex'],
                  animations: [
                      matExpansionAnimations.indicatorRotate,
                  ],
                  host: {
                      'class': 'mat-expansion-panel-header mat-focus-indicator',
                      'role': 'button',
                      '[attr.id]': 'panel._headerId',
                      '[attr.tabindex]': 'tabIndex',
                      '[attr.aria-controls]': '_getPanelId()',
                      '[attr.aria-expanded]': '_isExpanded()',
                      '[attr.aria-disabled]': 'panel.disabled',
                      '[class.mat-expanded]': '_isExpanded()',
                      '[class.mat-expansion-toggle-indicator-after]': `_getTogglePosition() === 'after'`,
                      '[class.mat-expansion-toggle-indicator-before]': `_getTogglePosition() === 'before'`,
                      '[class._mat-animation-noopable]': '_animationMode === "NoopAnimations"',
                      '[style.height]': '_getHeaderHeight()',
                      '(click)': '_toggle()',
                      '(keydown)': '_keydown($event)',
                  },
                  styles: [".mat-expansion-panel-header{display:flex;flex-direction:row;align-items:center;padding:0 24px;border-radius:inherit;transition:height 225ms cubic-bezier(0.4, 0, 0.2, 1)}.mat-expansion-panel-header._mat-animation-noopable{transition:none}.mat-expansion-panel-header:focus,.mat-expansion-panel-header:hover{outline:none}.mat-expansion-panel-header.mat-expanded:focus,.mat-expansion-panel-header.mat-expanded:hover{background:inherit}.mat-expansion-panel-header:not([aria-disabled=true]){cursor:pointer}.mat-expansion-panel-header.mat-expansion-toggle-indicator-before{flex-direction:row-reverse}.mat-expansion-panel-header.mat-expansion-toggle-indicator-before .mat-expansion-indicator{margin:0 16px 0 0}[dir=rtl] .mat-expansion-panel-header.mat-expansion-toggle-indicator-before .mat-expansion-indicator{margin:0 0 0 16px}.mat-content{display:flex;flex:1;flex-direction:row;overflow:hidden}.mat-expansion-panel-header-title,.mat-expansion-panel-header-description{display:flex;flex-grow:1;margin-right:16px}[dir=rtl] .mat-expansion-panel-header-title,[dir=rtl] .mat-expansion-panel-header-description{margin-right:0;margin-left:16px}.mat-expansion-panel-header-description{flex-grow:2}.mat-expansion-indicator::after{border-style:solid;border-width:0 2px 2px 0;content:\"\";display:inline-block;padding:3px;transform:rotate(45deg);vertical-align:middle}.cdk-high-contrast-active .mat-expansion-panel .mat-expansion-panel-header.cdk-keyboard-focused:not([aria-disabled=true])::before,.cdk-high-contrast-active .mat-expansion-panel .mat-expansion-panel-header.cdk-program-focused:not([aria-disabled=true])::before,.cdk-high-contrast-active .mat-expansion-panel:not(.mat-expanded) .mat-expansion-panel-header:hover:not([aria-disabled=true])::before{top:0;left:0;right:0;bottom:0;position:absolute;box-sizing:border-box;pointer-events:none;border:3px solid;border-radius:4px;content:\"\"}\n"]
              },] }
  ];
  MatExpansionPanelHeader.ctorParameters = () => [
      { type: MatExpansionPanel, decorators: [{ type: Host }] },
      { type: ElementRef },
      { type: FocusMonitor },
      { type: ChangeDetectorRef },
      { type: undefined, decorators: [{ type: Inject, args: [MAT_EXPANSION_PANEL_DEFAULT_OPTIONS,] }, { type: Optional }] },
      { type: String, decorators: [{ type: Optional }, { type: Inject, args: [ANIMATION_MODULE_TYPE,] }] },
      { type: String, decorators: [{ type: Attribute, args: ['tabindex',] }] }
  ];
  MatExpansionPanelHeader.propDecorators = {
      expandedHeight: [{ type: Input }],
      collapsedHeight: [{ type: Input }]
  };
  /**
   * Description element of a `<mat-expansion-panel-header>`.
   */
  class MatExpansionPanelDescription {
  }
  MatExpansionPanelDescription.decorators = [
      { type: Directive, args: [{
                  selector: 'mat-panel-description',
                  host: {
                      class: 'mat-expansion-panel-header-description'
                  }
              },] }
  ];
  /**
   * Title element of a `<mat-expansion-panel-header>`.
   */
  class MatExpansionPanelTitle {
  }
  MatExpansionPanelTitle.decorators = [
      { type: Directive, args: [{
                  selector: 'mat-panel-title',
                  host: {
                      class: 'mat-expansion-panel-header-title'
                  }
              },] }
  ];
  
  /**
   * @license
   * Copyright Google LLC All Rights Reserved.
   *
   * Use of this source code is governed by an MIT-style license that can be
   * found in the LICENSE file at https://angular.io/license
   */
  /**
   * Directive for a Material Design Accordion.
   */
  class MatAccordion extends CdkAccordion {
      constructor() {
          super(...arguments);
          /** Headers belonging to this accordion. */
          this._ownHeaders = new QueryList();
          this._hideToggle = false;
          /**
           * Display mode used for all expansion panels in the accordion. Currently two display
           * modes exist:
           *  default - a gutter-like spacing is placed around any expanded panel, placing the expanded
           *     panel at a different elevation from the rest of the accordion.
           *  flat - no spacing is placed around expanded panels, showing all panels at the same
           *     elevation.
           */
          this.displayMode = 'default';
          /** The position of the expansion indicator. */
          this.togglePosition = 'after';
      }
      /** Whether the expansion indicator should be hidden. */
      get hideToggle() { return this._hideToggle; }
      set hideToggle(show) { this._hideToggle = coerceBooleanProperty(show); }
      ngAfterContentInit() {
          this._headers.changes
              .pipe(startWith(this._headers))
              .subscribe((headers) => {
              this._ownHeaders.reset(headers.filter(header => header.panel.accordion === this));
              this._ownHeaders.notifyOnChanges();
          });
          this._keyManager = new FocusKeyManager(this._ownHeaders).withWrap().withHomeAndEnd();
      }
      /** Handles keyboard events coming in from the panel headers. */
      _handleHeaderKeydown(event) {
          this._keyManager.onKeydown(event);
      }
      _handleHeaderFocus(header) {
          this._keyManager.updateActiveItem(header);
      }
      ngOnDestroy() {
          super.ngOnDestroy();
          this._ownHeaders.destroy();
      }
  }
  MatAccordion.decorators = [
      { type: Directive, args: [{
                  selector: 'mat-accordion',
                  exportAs: 'matAccordion',
                  inputs: ['multi'],
                  providers: [{
                          provide: MAT_ACCORDION,
                          useExisting: MatAccordion
                      }],
                  host: {
                      class: 'mat-accordion',
                      // Class binding which is only used by the test harness as there is no other
                      // way for the harness to detect if multiple panel support is enabled.
                      '[class.mat-accordion-multi]': 'this.multi',
                  }
              },] }
  ];
  MatAccordion.propDecorators = {
      _headers: [{ type: ContentChildren, args: [MatExpansionPanelHeader, { descendants: true },] }],
      hideToggle: [{ type: Input }],
      displayMode: [{ type: Input }],
      togglePosition: [{ type: Input }]
  };
  
  /**
   * @license
   * Copyright Google LLC All Rights Reserved.
   *
   * Use of this source code is governed by an MIT-style license that can be
   * found in the LICENSE file at https://angular.io/license
   */
  class MatExpansionModule {
  }
  MatExpansionModule.decorators = [
      { type: NgModule, args: [{
                  imports: [CommonModule, MatCommonModule, CdkAccordionModule, PortalModule],
                  exports: [
                      MatAccordion,
                      MatExpansionPanel,
                      MatExpansionPanelActionRow,
                      MatExpansionPanelHeader,
                      MatExpansionPanelTitle,
                      MatExpansionPanelDescription,
                      MatExpansionPanelContent,
                  ],
                  declarations: [
                      MatAccordion,
                      MatExpansionPanel,
                      MatExpansionPanelActionRow,
                      MatExpansionPanelHeader,
                      MatExpansionPanelTitle,
                      MatExpansionPanelDescription,
                      MatExpansionPanelContent,
                  ],
              },] }
  ];
  
  /**
   * @license
   * Copyright Google LLC All Rights Reserved.
   *
   * Use of this source code is governed by an MIT-style license that can be
   * found in the LICENSE file at https://angular.io/license
   */
  
  /**
   * Generated bundle index. Do not edit.
   */
  
  export { EXPANSION_PANEL_ANIMATION_TIMING, MAT_ACCORDION, MAT_EXPANSION_PANEL_DEFAULT_OPTIONS, MatAccordion, MatExpansionModule, MatExpansionPanel, MatExpansionPanelActionRow, MatExpansionPanelContent, MatExpansionPanelDescription, MatExpansionPanelHeader, MatExpansionPanelTitle, matExpansionAnimations, ɵ0 };
  //# sourceMappingURL=expansion.js.map
  