Convert Guest class to TypeScript syntax

src/annotator/guest.js → src/annotator/guest.ts

@@ -25,37 +25,33 @@ import { findClosestOffscreenAnchor } from './util/buckets';
 import { frameFillsAncestor } from './util/frame';
 import { normalizeURI } from './util/url';
 
-/**
- * @typedef {import('../types/annotator').AnnotationData} AnnotationData
- * @typedef {import('../types/annotator').Annotator} Annotator
- * @typedef {import('../types/annotator').Anchor} Anchor
- * @typedef {import('../types/annotator').ContentInfoConfig} ContentInfoConfig
- * @typedef {import('../types/annotator').Destroyable} Destroyable
- * @typedef {import('../types/annotator').SidebarLayout} SidebarLayout
- * @typedef {import('../types/api').Target} Target
- * @typedef {import('../types/port-rpc-events').HostToGuestEvent} HostToGuestEvent
- * @typedef {import('../types/port-rpc-events').GuestToHostEvent} GuestToHostEvent
- * @typedef {import('../types/port-rpc-events').GuestToSidebarEvent} GuestToSidebarEvent
- * @typedef {import('../types/port-rpc-events').SidebarToGuestEvent} SidebarToGuestEvent
- */
-
-/**
- * HTML element created by the highlighter with an associated annotation.
- *
- * @typedef {HTMLElement & { _annotation?: AnnotationData }} AnnotationHighlight
- */
-
-/**
- * Return all the annotations tags associated with the selected text.
- *
- * @return {string[]}
- */
-function annotationsForSelection() {
-  const selection = /** @type {Selection} */ (window.getSelection());
+import type {
+  AnnotationData,
+  Annotator,
+  Anchor,
+  ContentInfoConfig,
+  Destroyable,
+  Integration,
+  SidebarLayout,
+} from '../types/annotator';
+import type { Target } from '../types/api';
+import type {
+  HostToGuestEvent,
+  GuestToHostEvent,
+  GuestToSidebarEvent,
+  SidebarToGuestEvent,
+} from '../types/port-rpc-events';
+
+/** HTML element created by the highlighter with an associated annotation. */
+type AnnotationHighlight = HTMLElement & { _annotation?: AnnotationData };
+
+/** Return all the annotations tags associated with the selected text. */
+function annotationsForSelection(): string[] {
+  const selection = window.getSelection()!;
   const range = selection.getRangeAt(0);
   const tags = rangeUtil.itemsForRange(
     range,
-    node => /** @type {AnnotationHighlight} */ (node)._annotation?.$tag
+    node => (node as AnnotationHighlight)._annotation?.$tag
   );
   return tags;
 }
@@ -63,16 +59,13 @@ function annotationsForSelection() {
 /**
  * Return the annotation tags associated with any highlights that contain a given
  * DOM node.
- *
- * @param {Node} node
- * @return {string[]}
  */
-function annotationsAt(node) {
+function annotationsAt(node: Node): string[] {
   const items = getHighlightsContainingNode(node)
-    .map(h => /** @type {AnnotationHighlight} */ (h)._annotation)
+    .map(h => (h as AnnotationHighlight)._annotation)
     .filter(ann => ann !== undefined)
     .map(ann => ann?.$tag);
-  return /** @type {string[]} */ (items);
+  return items as string[];
 }
 
 /**
@@ -80,11 +73,8 @@ function annotationsAt(node) {
  *
  * This may fail if anchoring failed or if the document has been mutated since
  * the anchor was created in a way that invalidates the anchor.
- *
- * @param {Anchor} anchor
- * @return {Range|null}
  */
-function resolveAnchor(anchor) {
+function resolveAnchor(anchor: Anchor): Range | null {
   if (!anchor.range) {
     return null;
   }
@@ -101,14 +91,17 @@ function removeTextSelection() {
 
 /**
  * Subset of the Hypothesis client configuration that is used by {@link Guest}.
- *
- * @typedef GuestConfig
- * @prop {string} [subFrameIdentifier] - An identifier used by this guest to
- *   identify the current frame when communicating with the sidebar. This is
- *   only set in non-host frames.
- * @prop {ContentInfoConfig} [contentInfoBanner] - Configures a banner or other indicators
- *   showing where the content has come from.
  */
+export type GuestConfig = {
+  /**
+   * An identifier used by this guest to identify the current frame when
+   * communicating with the sidebar. This is only set in non-host frames.
+   */
+  subFrameIdentifier?: string;
+
+  /** Configures a banner or other indicators showing where the content has come from. */
+  contentInfoBanner?: ContentInfoConfig;
+};
 
 /**
  * `Guest` is the central class of the annotator that handles anchoring (locating)
@@ -126,27 +119,83 @@ function removeTextSelection() {
  * class that shows the sidebar app and surrounding UI. The `Guest` instance in
  * each frame connects to the sidebar and host frames as part of its
  * initialization.
- *
- * @implements {Annotator}
- * @implements {Destroyable}
  */
-export class Guest {
+export class Guest implements Annotator, Destroyable {
+  public element: HTMLElement;
+
+  /** Ranges of the current text selection. */
+  public selectedRanges: Range[];
+
   /**
-   * @param {HTMLElement} element -
+   * The anchors generated by resolving annotation selectors to locations in the
+   * document. These are added by `anchor` and removed by `detach`.
+   *
+   * There is one anchor per annotation `Target`, which typically means one
+   * anchor per annotation.
+   */
+  public anchors: Anchor[];
+
+  public features: FeatureFlags;
+
+  private _adder: Adder;
+  private _clusterToolbar?: HighlightClusterController;
+  private _hostFrame: Window;
+  private _highlightsVisible: boolean;
+  private _isAdderVisible: boolean;
+  private _informHostOnNextSelectionClear: boolean;
+  private _selectionObserver: SelectionObserver;
+
+  /**
+   * Tags of annotations that are currently anchored or being anchored in
+   * the guest.
+   */
+  private _annotations: Set<string>;
+  private _frameIdentifier: string | null;
+  private _portFinder: PortFinder;
+
+  /**
+   * Integration that handles document-type specific functionality in the
+   * guest.
+   */
+  private _integration: Integration;
+
+  /** Channel for host-guest communication. */
+  private _hostRPC: PortRPC<HostToGuestEvent, GuestToHostEvent>;
+
+  /** Channel for guest-sidebar communication. */
+  private _sidebarRPC: PortRPC<SidebarToGuestEvent, GuestToSidebarEvent>;
+
+  private _bucketBarClient: BucketBarClient;
+
+  private _sideBySideActive: boolean;
+  private _listeners: ListenerCollection;
+
+  /**
+   * Tags of currently hovered annotations. This is used to set the hovered
+   * state correctly for new highlights if the associated annotation is already
+   * hovered in the sidebar.
+   */
+  private _hoveredAnnotations: Set<string>;
+
+  /**
+   * @param element -
    *   The root element in which the `Guest` instance should be able to anchor
    *   or create annotations. In an ordinary web page this typically `document.body`.
-   * @param {GuestConfig} [config]
-   * @param {Window} [hostFrame] -
+   * @param [config]
+   * @param [hostFrame] -
    *   Host frame which this guest is associated with. This is expected to be
    *   an ancestor of the guest frame. It may be same or cross origin.
    */
-  constructor(element, config = {}, hostFrame = window) {
+  constructor(
+    element: HTMLElement,
+    config: GuestConfig = {},
+    hostFrame: Window = window
+  ) {
     this.element = element;
     this._hostFrame = hostFrame;
     this._highlightsVisible = false;
     this._isAdderVisible = false;
     this._informHostOnNextSelectionClear = true;
-    /** @type {Range[]} - Ranges of the current text selection. */
     this.selectedRanges = [];
 
     this._adder = new Adder(this.element, {
@@ -170,26 +219,11 @@ export class Guest {
       }
     });
 
-    /**
-     * The anchors generated by resolving annotation selectors to locations in the
-     * document. These are added by `anchor` and removed by `detach`.
-     *
-     * There is one anchor per annotation `Target`, which typically means one
-     * anchor per annotation.
-     *
-     * @type {Anchor[]}
-     */
     this.anchors = [];
-
-    /**
-     * Tags of annotations that are currently anchored or being anchored in
-     * the guest.
-     */
-    this._annotations = /** @type {Set<string>} */ (new Set());
+    this._annotations = new Set();
 
     // Set the frame identifier if it's available.
     // The "top" guest instance will have this as null since it's in a top frame not a sub frame
-    /** @type {string|null} */
     this._frameIdentifier = config.subFrameIdentifier || null;
 
     this._portFinder = new PortFinder({
@@ -199,10 +233,7 @@ export class Guest {
     });
 
     this.features = new FeatureFlags();
-    /**
-     * Integration that handles document-type specific functionality in the
-     * guest.
-     */
+
     this._integration = createIntegration(this);
     this._integration.on('uriChanged', async () => {
       const metadata = await this.getDocumentInfo();
@@ -218,19 +249,9 @@ export class Guest {
       });
     }
 
-    /**
-     * Channel for host-guest communication.
-     *
-     * @type {PortRPC<HostToGuestEvent, GuestToHostEvent>}
-     */
     this._hostRPC = new PortRPC();
     this._connectHost(hostFrame);
 
-    /**
-     * Channel for guest-sidebar communication.
-     *
-     * @type {PortRPC<SidebarToGuestEvent, GuestToSidebarEvent>}
-     */
     this._sidebarRPC = new PortRPC();
     this._connectSidebar();
 
@@ -245,13 +266,6 @@ export class Guest {
     this._listeners = new ListenerCollection();
     this._setupElementEvents();
 
-    /**
-     * Tags of currently hovered annotations. This is used to set the hovered
-     * state correctly for new highlights if the associated annotation is already
-     * hovered in the sidebar.
-     *
-     * @type {Set<string>}
-     */
     this._hoveredAnnotations = new Set();
   }
 
@@ -260,8 +274,7 @@ export class Guest {
   _setupElementEvents() {
     // Hide the sidebar in response to a document click or tap, so it doesn't obscure
     // the document content.
-    /** @param {Element} element */
-    const maybeCloseSidebar = element => {
+    const maybeCloseSidebar = (element: Element) => {
       if (this._sideBySideActive) {
         // Don't hide the sidebar if event was disabled because the sidebar
         // doesn't overlap the content.
@@ -276,7 +289,7 @@ export class Guest {
 
     this._listeners.add(this.element, 'mouseup', event => {
       const { target, metaKey, ctrlKey } = event;
-      const tags = annotationsAt(/** @type {Element} */ (target));
+      const tags = annotationsAt(target as Element);
       if (tags.length && this._highlightsVisible) {
         const toggle = metaKey || ctrlKey;
         this.selectAnnotations(tags, { toggle });
@@ -284,17 +297,17 @@ export class Guest {
     });
 
     this._listeners.add(this.element, 'mousedown', ({ target }) => {
-      maybeCloseSidebar(/** @type {Element} */ (target));
+      maybeCloseSidebar(target as Element);
     });
 
     // Allow taps on the document to hide the sidebar as well as clicks.
     // On iOS < 13 (2019), elements like h2 or div don't emit 'click' events.
     this._listeners.add(this.element, 'touchstart', ({ target }) => {
-      maybeCloseSidebar(/** @type {Element} */ (target));
+      maybeCloseSidebar(target as Element);
     });
 
     this._listeners.add(this.element, 'mouseover', ({ target }) => {
-      const tags = annotationsAt(/** @type {Element} */ (target));
+      const tags = annotationsAt(target as Element);
       if (tags.length && this._highlightsVisible) {
         this._sidebarRPC.call('hoverAnnotations', tags);
       }
@@ -343,8 +356,7 @@ export class Guest {
     }
   }
 
-  /** @param {Window} hostFrame */
-  async _connectHost(hostFrame) {
+  async _connectHost(hostFrame: Window) {
     this._hostRPC.on('clearSelection', () => {
       if (selectedRange(document)) {
         this._informHostOnNextSelectionClear = false;
@@ -354,39 +366,25 @@ export class Guest {
 
     this._hostRPC.on('createAnnotation', () => this.createAnnotation());
 
-    this._hostRPC.on(
-      'hoverAnnotations',
-      /** @param {string[]} tags */
-      tags => this._hoverAnnotations(tags)
+    this._hostRPC.on('hoverAnnotations', (tags: string[]) =>
+      this._hoverAnnotations(tags)
     );
 
     this._hostRPC.on(
       'scrollToClosestOffScreenAnchor',
-      /**
-       * @param {string[]} tags
-       * @param {'down'|'up'} direction
-       */
-      (tags, direction) => this._scrollToClosestOffScreenAnchor(tags, direction)
+      (tags: string[], direction: 'down' | 'up') =>
+        this._scrollToClosestOffScreenAnchor(tags, direction)
     );
 
-    this._hostRPC.on(
-      'selectAnnotations',
-      /**
-       * @param {string[]} tags
-       * @param {boolean} toggle
-       */
-      (tags, toggle) => this.selectAnnotations(tags, { toggle })
+    this._hostRPC.on('selectAnnotations', (tags: string[], toggle: boolean) =>
+      this.selectAnnotations(tags, { toggle })
     );
 
-    this._hostRPC.on(
-      'sidebarLayoutChanged',
-      /** @param {SidebarLayout} sidebarLayout */
-      sidebarLayout => {
-        if (frameFillsAncestor(window, hostFrame)) {
-          this.fitSideBySide(sidebarLayout);
-        }
+    this._hostRPC.on('sidebarLayoutChanged', (sidebarLayout: SidebarLayout) => {
+      if (frameFillsAncestor(window, hostFrame)) {
+        this.fitSideBySide(sidebarLayout);
       }
-    );
+    });
 
     // Discover and connect to the host frame. All RPC events must be
     // registered before creating the channel.
@@ -397,71 +395,53 @@ export class Guest {
   async _connectSidebar() {
     this._sidebarRPC.on(
       'featureFlagsUpdated',
-      /** @param {Record<string, boolean>} flags */ flags =>
-        this.features.update(flags)
+      (flags: Record<string, boolean>) => this.features.update(flags)
     );
 
     // Handlers for events sent when user hovers or clicks on an annotation card
     // in the sidebar.
-    this._sidebarRPC.on(
-      'hoverAnnotations',
-      /** @param {string[]} tags */
-      tags => this._hoverAnnotations(tags)
+    this._sidebarRPC.on('hoverAnnotations', (tags: string[]) =>
+      this._hoverAnnotations(tags)
     );
 
-    this._sidebarRPC.on(
-      'scrollToAnnotation',
-      /** @param {string} tag */
-      tag => {
-        const anchor = this.anchors.find(a => a.annotation.$tag === tag);
-        if (!anchor?.highlights) {
-          return;
-        }
-        const range = resolveAnchor(anchor);
-        if (!range) {
-          return;
-        }
-
-        // Emit a custom event that the host page can respond to. This is useful,
-        // for example, if the highlighted content is contained in a collapsible
-        // section of the page that needs to be un-collapsed.
-        const event = new CustomEvent('scrolltorange', {
-          bubbles: true,
-          cancelable: true,
-          detail: range,
-        });
-        const defaultNotPrevented = this.element.dispatchEvent(event);
-
-        if (defaultNotPrevented) {
-          this._integration.scrollToAnchor(anchor);
-        }
+    this._sidebarRPC.on('scrollToAnnotation', (tag: string) => {
+      const anchor = this.anchors.find(a => a.annotation.$tag === tag);
+      if (!anchor?.highlights) {
+        return;
+      }
+      const range = resolveAnchor(anchor);
+      if (!range) {
+        return;
       }
-    );
 
-    // Handler for controls on the sidebar
-    this._sidebarRPC.on(
-      'setHighlightsVisible',
-      /** @param {boolean} showHighlights */ showHighlights => {
-        this.setHighlightsVisible(showHighlights, false /* notifyHost */);
+      // Emit a custom event that the host page can respond to. This is useful,
+      // for example, if the highlighted content is contained in a collapsible
+      // section of the page that needs to be un-collapsed.
+      const event = new CustomEvent('scrolltorange', {
+        bubbles: true,
+        cancelable: true,
+        detail: range,
+      });
+      const defaultNotPrevented = this.element.dispatchEvent(event);
+
+      if (defaultNotPrevented) {
+        this._integration.scrollToAnchor(anchor);
       }
-    );
+    });
 
-    this._sidebarRPC.on(
-      'deleteAnnotation',
-      /** @param {string} tag */
-      tag => this.detach(tag)
-    );
+    // Handler for controls on the sidebar
+    this._sidebarRPC.on('setHighlightsVisible', (showHighlights: boolean) => {
+      this.setHighlightsVisible(showHighlights, false /* notifyHost */);
+    });
 
-    this._sidebarRPC.on(
-      'loadAnnotations',
-      /** @param {AnnotationData[]} annotations */
-      annotations => annotations.forEach(annotation => this.anchor(annotation))
+    this._sidebarRPC.on('deleteAnnotation', (tag: string) => this.detach(tag));
+
+    this._sidebarRPC.on('loadAnnotations', (annotations: AnnotationData[]) =>
+      annotations.forEach(annotation => this.anchor(annotation))
     );
 
-    this._sidebarRPC.on(
-      'showContentInfo',
-      /** @param {ContentInfoConfig} info */
-      info => this._integration.showContentInfo?.(info)
+    this._sidebarRPC.on('showContentInfo', (info: ContentInfoConfig) =>
+      this._integration.showContentInfo?.(info)
     );
 
     // Connect to sidebar and send document info/URIs to it.
@@ -501,18 +481,12 @@ export class Guest {
    *
    * Any existing anchors associated with `annotation` will be removed before
    * re-anchoring the annotation.
-   *
-   * @param {AnnotationData} annotation
-   * @return {Promise<Anchor[]>}
    */
-  async anchor(annotation) {
+  async anchor(annotation: AnnotationData): Promise<Anchor[]> {
     /**
      * Resolve an annotation's selectors to a concrete range.
-     *
-     * @param {Target} target
-     * @return {Promise<Anchor>}
      */
-    const locate = async target => {
+    const locate = async (target: Target): Promise<Anchor> => {
       // Only annotations with an associated quote can currently be anchored.
       // This is because the quote is used to verify anchoring with other selector
       // types.
@@ -523,8 +497,7 @@ export class Guest {
         return { annotation, target };
       }
 
-      /** @type {Anchor} */
-      let anchor;
+      let anchor: Anchor;
       try {
         const range = await this._integration.anchor(
           this.element,
@@ -544,21 +517,17 @@ export class Guest {
 
     /**
      * Highlight the text range that `anchor` refers to.
-     *
-     * @param {Anchor} anchor
      */
-    const highlight = anchor => {
+    const highlight = (anchor: Anchor) => {
       const range = resolveAnchor(anchor);
       if (!range) {
         return;
       }
 
-      const highlights = /** @type {AnnotationHighlight[]} */ (
-        highlightRange(
-          range,
-          classnames('hypothesis-highlight', anchor.annotation?.$cluster)
-        )
-      );
+      const highlights = highlightRange(
+        range,
+        classnames('hypothesis-highlight', anchor.annotation?.$cluster)
+      ) as AnnotationHighlight[];
       highlights.forEach(h => {
         h._annotation = anchor.annotation;
       });
@@ -585,7 +554,7 @@ export class Guest {
       return [];
     }
 
-    for (let anchor of anchors) {
+    for (const anchor of anchors) {
       highlight(anchor);
     }
 
@@ -607,16 +576,14 @@ export class Guest {
   /**
    * Remove the anchors and associated highlights for an annotation from the document.
    *
-   * @param {string} tag
-   * @param {boolean} [notify] - For internal use. Whether to inform the host
+   * @param [notify] - For internal use. Whether to inform the host
    *   frame about the removal of an anchor.
    */
-  detach(tag, notify = true) {
+  detach(tag: string, notify = true) {
     this._annotations.delete(tag);
 
-    /** @type {Anchor[]} */
-    const anchors = [];
-    for (let anchor of this.anchors) {
+    const anchors = [] as Anchor[];
+    for (const anchor of this.anchors) {
       if (anchor.annotation.$tag !== tag) {
         anchors.push(anchor);
       } else if (anchor.highlights) {
@@ -626,11 +593,7 @@ export class Guest {
     this._updateAnchors(anchors, notify);
   }
 
-  /**
-   * @param {Anchor[]} anchors
-   * @param {boolean} notify
-   */
-  _updateAnchors(anchors, notify) {
+  _updateAnchors(anchors: Anchor[], notify: boolean) {
     this.anchors = anchors;
     if (notify) {
       this._bucketBarClient.update(this.anchors);
@@ -641,13 +604,13 @@ export class Guest {
    * Create a new annotation that is associated with the selected region of
    * the current document.
    *
-   * @param {object} options
-   *   @param {boolean} [options.highlight] - If true, the new annotation has
+   * @param options
+   *   @param [options.highlight] - If true, the new annotation has
    *     the `$highlight` flag set, causing it to be saved immediately without
    *     prompting for a comment.
-   * @return {Promise<AnnotationData>} - The new annotation
+   * @return The new annotation
    */
-  async createAnnotation({ highlight = false } = {}) {
+  async createAnnotation({ highlight = false } = {}): Promise<AnnotationData> {
     const ranges = this.selectedRanges;
     this.selectedRanges = [];
 
@@ -664,8 +627,7 @@ export class Guest {
       selector: selectors,
     }));
 
-    /** @type {AnnotationData} */
-    const annotation = {
+    const annotation: AnnotationData = {
       uri: info.uri,
       document: info.metadata,
       target,
@@ -687,14 +649,12 @@ export class Guest {
   /**
    * Indicate in the sidebar that certain annotations are focused (ie. the
    * associated document region(s) is hovered).
-   *
-   * @param {string[]} tags
    */
-  _hoverAnnotations(tags) {
+  _hoverAnnotations(tags: string[]) {
     this._hoveredAnnotations.clear();
     tags.forEach(tag => this._hoveredAnnotations.add(tag));
 
-    for (let anchor of this.anchors) {
+    for (const anchor of this.anchors) {
       if (anchor.highlights) {
         const toggle = tags.includes(anchor.annotation.$tag);
         setHighlightsFocused(anchor.highlights, toggle);
@@ -706,11 +666,8 @@ export class Guest {
 
   /**
    * Scroll to the closest off screen anchor.
-   *
-   * @param {string[]} tags
-   * @param {'down'|'up'} direction
    */
-  _scrollToClosestOffScreenAnchor(tags, direction) {
+  _scrollToClosestOffScreenAnchor(tags: string[], direction: 'down' | 'up') {
     const anchors = this.anchors.filter(({ annotation }) =>
       tags.includes(annotation.$tag)
     );
@@ -722,16 +679,14 @@ export class Guest {
 
   /**
    * Show or hide the adder toolbar when the selection changes.
-   *
-   * @param {Range} range
    */
-  _onSelection(range) {
+  _onSelection(range: Range) {
     if (!this._integration.canAnnotate(range)) {
       this._onClearSelection();
       return;
     }
 
-    const selection = /** @type {Selection} */ (document.getSelection());
+    const selection = document.getSelection()!;
     const isBackwards = rangeUtil.isSelectionBackwards(selection);
     const focusRect = rangeUtil.selectionFocusRect(selection);
     if (!focusRect) {
@@ -765,15 +720,18 @@ export class Guest {
    * and opens the sidebar. Optionally it can also transfer keyboard focus to
    * the annotation card for the first selected annotation.
    *
-   * @param {string[]} tags
-   * @param {object} options
-   *   @param {boolean} [options.toggle] - Toggle whether the annotations are
+   * @param tags
+   * @param options
+   *   @param [options.toggle] - Toggle whether the annotations are
    *     selected, as opposed to just selecting them
-   *   @param {boolean} [options.focusInSidebar] - Whether to transfer keyboard
+   *   @param [options.focusInSidebar] - Whether to transfer keyboard
    *     focus to the card for the first annotation in the selection. This
    *     option has no effect if {@link toggle} is true.
    */
-  selectAnnotations(tags, { toggle = false, focusInSidebar = false } = {}) {
+  selectAnnotations(
+    tags: string[],
+    { toggle = false, focusInSidebar = false } = {}
+  ) {
     if (toggle) {
       this._sidebarRPC.call('toggleAnnotationSelection', tags);
     } else {
@@ -785,12 +743,12 @@ export class Guest {
   /**
    * Set whether highlights are visible in the document or not.
    *
-   * @param {boolean} visible
-   * @param {boolean} notifyHost - Whether to notify the host frame about this
+   * @param visible
+   * @param notifyHost - Whether to notify the host frame about this
    *   change. This should be true unless the request to change highlight
    *   visibility is coming from the host frame.
    */
-  setHighlightsVisible(visible, notifyHost = true) {
+  setHighlightsVisible(visible: boolean, notifyHost = true) {
     setHighlightsVisible(this.element, visible);
     this._highlightsVisible = visible;
     if (notifyHost) {
@@ -805,9 +763,9 @@ export class Guest {
   /**
    * Attempt to fit the document content alongside the sidebar.
    *
-   * @param {SidebarLayout} sidebarLayout
+   * @param sidebarLayout
    */
-  fitSideBySide(sidebarLayout) {
+  fitSideBySide(sidebarLayout: SidebarLayout) {
     this._sideBySideActive = this._integration.fitSideBySide(sidebarLayout);
   }
 
@@ -825,19 +783,15 @@ export class Guest {
   /**
    * Return the tags of annotations that are currently displayed in a hovered
    * state.
-   *
-   * @return {Set<string>}
    */
-  get hoveredAnnotationTags() {
+  get hoveredAnnotationTags(): Set<string> {
     return this._hoveredAnnotations;
   }
 
   /**
    * Handle a potential shortcut trigger.
-   *
-   * @param {KeyboardEvent} event
    */
-  _handleShortcut(event) {
+  _handleShortcut(event: KeyboardEvent) {
     if (matchShortcut(event, 'Ctrl+Shift+H')) {
       this.setHighlightsVisible(!this._highlightsVisible);
     }