diff --git a/src/core/ccitt.js b/src/core/ccitt.js
index 2f9bb4fe0..3f81e339a 100644
--- a/src/core/ccitt.js
+++ b/src/core/ccitt.js
@@ -458,7 +458,7 @@ let CCITTFaxDecoder = (function CCITTFaxDecoder() {
 
   /**
    * @param {CCITTFaxDecoderSource} source - The data which should be decoded.
-   * @param {Object} options - (optional) Decoding options.
+   * @param {Object} [options] - Decoding options.
    */
   function CCITTFaxDecoder(source, options = {}) {
     if (!source || typeof source.next !== 'function') {
diff --git a/src/core/obj.js b/src/core/obj.js
index 9b74c7b1b..e854e1e1f 100644
--- a/src/core/obj.js
+++ b/src/core/obj.js
@@ -863,8 +863,8 @@ class Catalog {
    * @property {Dict} destDict - The dictionary containing the destination.
    * @property {Object} resultObj - The object where the parsed destination
    *   properties will be placed.
-   * @property {string} docBaseUrl - (optional) The document base URL that is
-   *   used when attempting to recover valid absolute URLs from relative ones.
+   * @property {string} [docBaseUrl] - The document base URL that is used when
+   *   attempting to recover valid absolute URLs from relative ones.
    */
 
   /**
diff --git a/src/display/annotation_layer.js b/src/display/annotation_layer.js
index fdf06a62e..9bd3c08ee 100644
--- a/src/display/annotation_layer.js
+++ b/src/display/annotation_layer.js
@@ -31,8 +31,8 @@ import {
  * @property {PageViewport} viewport
  * @property {IPDFLinkService} linkService
  * @property {DownloadManager} downloadManager
- * @property {string} imageResourcesPath - (optional) Path for image resources,
- *   mainly for annotation icons. Include trailing slash.
+ * @property {string} [imageResourcesPath] - Path for image resources, mainly
+ *   for annotation icons. Include trailing slash.
  * @property {boolean} renderInteractiveForms
  * @property {Object} svgFactory
  */
@@ -1328,8 +1328,8 @@ class FileAttachmentAnnotationElement extends AnnotationElement {
  * @property {PDFPage} page
  * @property {IPDFLinkService} linkService
  * @property {DownloadManager} downloadManager
- * @property {string} imageResourcesPath - (optional) Path for image resources,
- *   mainly for annotation icons. Include trailing slash.
+ * @property {string} [imageResourcesPath] - Path for image resources, mainly
+ *   for annotation icons. Include trailing slash.
  * @property {boolean} renderInteractiveForms
  */
 
diff --git a/src/display/display_utils.js b/src/display/display_utils.js
index e2c47b3cf..aa671c802 100644
--- a/src/display/display_utils.js
+++ b/src/display/display_utils.js
@@ -160,22 +160,22 @@ class DOMSVGFactory {
  * @property {Array} viewBox - The xMin, yMin, xMax and yMax coordinates.
  * @property {number} scale - The scale of the viewport.
  * @property {number} rotation - The rotation, in degrees, of the viewport.
- * @property {number} offsetX - (optional) The horizontal, i.e. x-axis, offset.
- *   The default value is `0`.
- * @property {number} offsetY - (optional) The vertical, i.e. y-axis, offset.
- *   The default value is `0`.
- * @property {boolean} dontFlip - (optional) If true, the y-axis will not be
- *   flipped. The default value is `false`.
+ * @property {number} [offsetX] - The horizontal, i.e. x-axis, offset. The
+ *   default value is `0`.
+ * @property {number} [offsetY] - The vertical, i.e. y-axis, offset. The
+ *   default value is `0`.
+ * @property {boolean} [dontFlip] - If true, the y-axis will not be flipped.
+ *   The default value is `false`.
  */
 
 /**
  * @typedef {Object} PageViewportCloneParameters
- * @property {number} scale - (optional) The scale, overriding the one in the
- *   cloned viewport. The default value is `this.scale`.
- * @property {number} rotation - (optional) The rotation, in degrees, overriding
- *   the one in the cloned viewport. The default value is `this.rotation`.
- * @property {boolean} dontFlip - (optional) If true, the x-axis will not be
- *   flipped. The default value is `false`.
+ * @property {number} [scale] - The scale, overriding the one in the cloned
+ *   viewport. The default value is `this.scale`.
+ * @property {number} [rotation] - The rotation, in degrees, overriding the one
+ *   in the cloned viewport. The default value is `this.rotation`.
+ * @property {boolean} [dontFlip] - If true, the x-axis will not be flipped.
+ *   The default value is `false`.
  */
 
 /**
@@ -251,7 +251,7 @@ class PageViewport {
 
   /**
    * Clones viewport, with optional additional properties.
-   * @param {PageViewportCloneParameters} - (optional)
+   * @param {PageViewportCloneParameters} [params]
    * @return {PageViewport} Cloned viewport.
    */
   clone({ scale = this.scale, rotation = this.rotation,
@@ -334,12 +334,12 @@ const LinkTargetStringMap = [
  * @typedef ExternalLinkParameters
  * @typedef {Object} ExternalLinkParameters
  * @property {string} url - An absolute URL.
- * @property {LinkTarget} target - (optional) The link target.
- *   The default value is `LinkTarget.NONE`.
- * @property {string} rel - (optional) The link relationship.
- *   The default value is `DEFAULT_LINK_REL`.
- * @property {boolean} enabled - (optional) Whether the link should be enabled.
- *   The default value is true.
+ * @property {LinkTarget} [target] - The link target. The default value is
+ *   `LinkTarget.NONE`.
+ * @property {string} [rel] - The link relationship. The default value is
+ *   `DEFAULT_LINK_REL`.
+ * @property {boolean} [enabled] - Whether the link should be enabled. The
+ *   default value is true.
  */
 
 /**
diff --git a/src/display/text_layer.js b/src/display/text_layer.js
index 1bd06bfd5..d900d2d32 100644
--- a/src/display/text_layer.js
+++ b/src/display/text_layer.js
@@ -20,24 +20,23 @@ import globalScope from '../shared/global_scope';
  * Text layer render parameters.
  *
  * @typedef {Object} TextLayerRenderParameters
- * @property {TextContent} textContent - (optional) Text content to render
- *   (the object is returned by the page's getTextContent() method).
- * @property {ReadableStream} textContentStream - (optional) Text content
- *   stream to render (the stream is returned by the page's
- *   streamTextContent() method).
+ * @property {TextContent} [textContent] - Text content to render (the object
+ *   is returned by the page's `getTextContent` method).
+ * @property {ReadableStream} [textContentStream] - Text content stream to
+ *   render (the stream is returned by the page's `streamTextContent` method).
  * @property {HTMLElement} container - HTML element that will contain text runs.
  * @property {PageViewport} viewport - The target viewport to properly
  *   layout the text runs.
- * @property {Array} textDivs - (optional) HTML elements that are correspond
- *   the text items of the textContent input. This is output and shall be
+ * @property {Array} [textDivs] - HTML elements that are correspond to the
+ *   text items of the textContent input. This is output and shall be
  *   initially be set to empty array.
- * @property {Array} textContentItemsStr - (optional) Strings that correspond
- *   the `str` property of the text items of textContent input. This is output
+ * @property {Array} [textContentItemsStr] - Strings that correspond to the
+ *   `str` property of the text items of textContent input. This is output
  *   and shall be initially be set to empty array.
- * @property {number} timeout - (optional) Delay in milliseconds before
- *   rendering of the text  runs occurs.
- * @property {boolean} enhanceTextSelection - (optional) Whether to turn on the
- *   text selection enhancement.
+ * @property {number} [timeout] - Delay in milliseconds before rendering of the
+ *   text runs occurs.
+ * @property {boolean} [enhanceTextSelection] - Whether to turn on the text
+ *   selection enhancement.
  */
 var renderTextLayer = (function renderTextLayerClosure() {
   var MAX_TEXT_DIVS_TO_RENDER = 100000;
diff --git a/src/shared/message_handler.js b/src/shared/message_handler.js
index 869a4a92f..bed45e28a 100644
--- a/src/shared/message_handler.js
+++ b/src/shared/message_handler.js
@@ -134,7 +134,7 @@ MessageHandler.prototype = {
    * Sends a message to the comObj to invoke the action with the supplied data.
    * @param {string} actionName - Action to call.
    * @param {JSON} data - JSON data to send.
-   * @param {Array} [transfers] - Optional list of transfers/ArrayBuffers
+   * @param {Array} [transfers] - List of transfers/ArrayBuffers.
    */
   send(actionName, data, transfers) {
     this.postMessage({
@@ -149,7 +149,7 @@ MessageHandler.prototype = {
    * Expects that the other side will callback with the response.
    * @param {string} actionName - Action to call.
    * @param {JSON} data - JSON data to send.
-   * @param {Array} [transfers] - Optional list of transfers/ArrayBuffers.
+   * @param {Array} [transfers] - List of transfers/ArrayBuffers.
    * @returns {Promise} Promise to be resolved with response data.
    */
   sendWithPromise(actionName, data, transfers) {
@@ -174,9 +174,9 @@ MessageHandler.prototype = {
    * Expect that the other side will callback to signal 'start_complete'.
    * @param {string} actionName - Action to call.
    * @param {JSON} data - JSON data to send.
-   * @param {Object} queueingStrategy - strategy to signal backpressure based on
+   * @param {Object} queueingStrategy - Strategy to signal backpressure based on
    *                 internal queue.
-   * @param {Array} [transfers] - Optional list of transfers/ArrayBuffers.
+   * @param {Array} [transfers] - List of transfers/ArrayBuffers.
    * @return {ReadableStream} ReadableStream to read data in chunks.
    */
   sendWithStream(actionName, data, queueingStrategy, transfers) {
diff --git a/web/annotation_layer_builder.js b/web/annotation_layer_builder.js
index 10f1eeec0..9805c2e29 100644
--- a/web/annotation_layer_builder.js
+++ b/web/annotation_layer_builder.js
@@ -21,8 +21,8 @@ import { SimpleLinkService } from './pdf_link_service';
  * @typedef {Object} AnnotationLayerBuilderOptions
  * @property {HTMLDivElement} pageDiv
  * @property {PDFPage} pdfPage
- * @property {string} imageResourcesPath - (optional) Path for image resources,
- *   mainly for annotation icons. Include trailing slash.
+ * @property {string} [imageResourcesPath] - Path for image resources, mainly
+ *   for annotation icons. Include trailing slash.
  * @property {boolean} renderInteractiveForms
  * @property {IPDFLinkService} linkService
  * @property {DownloadManager} downloadManager
@@ -109,8 +109,8 @@ class DefaultAnnotationLayerFactory {
   /**
    * @param {HTMLDivElement} pageDiv
    * @param {PDFPage} pdfPage
-   * @param {string} imageResourcesPath - (optional) Path for image resources,
-   *   mainly for annotation icons. Include trailing slash.
+   * @param {string} [imageResourcesPath] - Path for image resources, mainly
+   *   for annotation icons. Include trailing slash.
    * @param {boolean} renderInteractiveForms
    * @param {IL10n} l10n
    * @returns {AnnotationLayerBuilder}
diff --git a/web/app.js b/web/app.js
index f8ca4d2ae..a0390ca15 100644
--- a/web/app.js
+++ b/web/app.js
@@ -609,9 +609,9 @@ let PDFViewerApplication = {
   /**
    * Opens PDF document specified by URL or array with additional arguments.
    * @param {string|TypedArray|ArrayBuffer} file - PDF location or binary data.
-   * @param {Object} args - (optional) Additional arguments for the getDocument
-   *                        call, e.g. HTTP headers ('httpHeaders') or
-   *                        alternative data transport ('range').
+   * @param {Object} [args] - Additional arguments for the getDocument call,
+   *                          e.g. HTTP headers ('httpHeaders') or alternative
+   *                          data transport ('range').
    * @returns {Promise} - Returns the promise, which is resolved when document
    *                      is opened.
    */
@@ -764,10 +764,10 @@ let PDFViewerApplication = {
 
   /**
    * Show the error box.
-   * @param {string} message A message that is human readable.
-   * @param {Object} moreInfo (optional) Further information about the error
-   *                            that is more technical.  Should have a 'message'
-   *                            and optionally a 'stack' property.
+   * @param {string} message - A message that is human readable.
+   * @param {Object} [moreInfo] - Further information about the error that is
+   *                              more technical.  Should have a 'message' and
+   *                              optionally a 'stack' property.
    */
   error(message, moreInfo) {
     let moreInfoText = [this.l10n.get('error_version_info',
diff --git a/web/base_viewer.js b/web/base_viewer.js
index ff10255d9..d7675e5c8 100644
--- a/web/base_viewer.js
+++ b/web/base_viewer.js
@@ -33,36 +33,35 @@ const DEFAULT_CACHE_SIZE = 10;
 /**
  * @typedef {Object} PDFViewerOptions
  * @property {HTMLDivElement} container - The container for the viewer element.
- * @property {HTMLDivElement} viewer - (optional) The viewer element.
+ * @property {HTMLDivElement} [viewer] - The viewer element.
  * @property {EventBus} eventBus - The application event bus.
  * @property {IPDFLinkService} linkService - The navigation/linking service.
- * @property {DownloadManager} downloadManager - (optional) The download
- *   manager component.
- * @property {PDFFindController} findController - (optional) The find
- *   controller component.
- * @property {PDFRenderingQueue} renderingQueue - (optional) The rendering
- *   queue object.
- * @property {boolean} removePageBorders - (optional) Removes the border shadow
- *   around the pages. The default value is `false`.
- * @property {number} textLayerMode - (optional) Controls if the text layer used
- *   for selection and searching is created, and if the improved text selection
+ * @property {DownloadManager} [downloadManager] - The download manager
+ *   component.
+ * @property {PDFFindController} [findController] - The find controller
+ *   component.
+ * @property {PDFRenderingQueue} [renderingQueue] - The rendering queue object.
+ * @property {boolean} [removePageBorders] - Removes the border shadow around
+ *   the pages. The default value is `false`.
+ * @property {number} [textLayerMode] - Controls if the text layer used for
+ *   selection and searching is created, and if the improved text selection
  *   behaviour is enabled. The constants from {TextLayerMode} should be used.
  *   The default value is `TextLayerMode.ENABLE`.
- * @property {string} imageResourcesPath - (optional) Path for image resources,
+ * @property {string} [imageResourcesPath] - Path for image resources, mainly
  *   mainly for annotation icons. Include trailing slash.
- * @property {boolean} renderInteractiveForms - (optional) Enables rendering of
+ * @property {boolean} [renderInteractiveForms] - Enables rendering of
  *   interactive form elements. The default is `false`.
- * @property {boolean} enablePrintAutoRotate - (optional) Enables automatic
- *   rotation of pages whose orientation differ from the first page upon
- *   printing. The default is `false`.
+ * @property {boolean} [enablePrintAutoRotate] - Enables automatic rotation of
+ *   pages whose orientation differ from the first page upon printing. The
+ *   default is `false`.
  * @property {string} renderer - 'canvas' or 'svg'. The default is 'canvas'.
- * @property {boolean} enableWebGL - (optional) Enables WebGL accelerated
- *   rendering for some operations. The default value is `false`.
- * @property {boolean} useOnlyCssZoom - (optional) Enables CSS only zooming.
- *   The default value is `false`.
- * @property {number} maxCanvasPixels - (optional) The maximum supported canvas
- *   size in total pixels, i.e. width * height. Use -1 for no limit.
- *   The default value is 4096 * 4096 (16 mega-pixels).
+ * @property {boolean} [enableWebGL] - Enables WebGL accelerated rendering for
+ *   some operations. The default value is `false`.
+ * @property {boolean} [useOnlyCssZoom] - Enables CSS only zooming. The default
+ *   value is `false`.
+ * @property {number} [maxCanvasPixels] - The maximum supported canvas size in
+ *   total pixels, i.e. width * height. Use -1 for no limit. The default value
+ *   is 4096 * 4096 (16 mega-pixels).
  * @property {IL10n} l10n - Localization service.
  */
 
@@ -666,10 +665,10 @@ class BaseViewer {
   /**
    * @typedef ScrollPageIntoViewParameters
    * @property {number} pageNumber - The page number.
-   * @property {Array} destArray - (optional) The original PDF destination
-   *   array, in the format: <page-ref> </XYZ|/FitXXX> <args..>
-   * @property {boolean} allowNegativeOffset - (optional) Allow negative page
-   *   offsets. The default value is `false`.
+   * @property {Array} [destArray] - The original PDF destination array, in the
+   *   format: <page-ref> </XYZ|/FitXXX> <args..>
+   * @property {boolean} [allowNegativeOffset] - Allow negative page offsets.
+   *   The default value is `false`.
    */
 
   /**
@@ -1009,8 +1008,8 @@ class BaseViewer {
   /**
    * @param {HTMLDivElement} pageDiv
    * @param {PDFPage} pdfPage
-   * @param {string} imageResourcesPath - (optional) Path for image resources,
-   *   mainly for annotation icons. Include trailing slash.
+   * @param {string} [imageResourcesPath] - Path for image resources, mainly
+   *   for annotation icons. Include trailing slash.
    * @param {boolean} renderInteractiveForms
    * @param {IL10n} l10n
    * @returns {AnnotationLayerBuilder}
diff --git a/web/chromecom.js b/web/chromecom.js
index 9b461e65d..96d84a200 100644
--- a/web/chromecom.js
+++ b/web/chromecom.js
@@ -30,11 +30,11 @@ let ChromeCom = {
    * Creates an event that the extension is listening for and will
    * asynchronously respond by calling the callback.
    *
-   * @param {string} action The action to trigger.
-   * @param {string} data Optional data to send.
-   * @param {Function} callback Optional response callback that will be called
-   * with one data argument. When the request cannot be handled, the callback
-   * is immediately invoked with no arguments.
+   * @param {string} action - The action to trigger.
+   * @param {string} [data] - The data to send.
+   * @param {Function} [callback] - Response callback that will be called with
+   *   one data argument. When the request cannot be handled, the callback is
+   *   immediately invoked with no arguments.
    */
   request(action, data, callback) {
     let message = {
diff --git a/web/firefoxcom.js b/web/firefoxcom.js
index e0af9fa12..05d31420f 100644
--- a/web/firefoxcom.js
+++ b/web/firefoxcom.js
@@ -32,8 +32,8 @@ let FirefoxCom = (function FirefoxComClosure() {
      * synchronously respond to.
      * NOTE: It is reccomended to use request() instead since one day we may not
      * be able to synchronously reply.
-     * @param {string} action The action to trigger.
-     * @param {string} data Optional data to send.
+     * @param {string} action - The action to trigger.
+     * @param {string} [data] - The data to send.
      * @return {*} The response.
      */
     requestSync(action, data) {
@@ -52,10 +52,10 @@ let FirefoxCom = (function FirefoxComClosure() {
     /**
      * Creates an event that the extension is listening for and will
      * asynchronously respond by calling the callback.
-     * @param {string} action The action to trigger.
-     * @param {string} data Optional data to send.
-     * @param {Function} callback Optional response callback that will be called
-     * with one data argument.
+     * @param {string} action - The action to trigger.
+     * @param {string} [data] - The data to send.
+     * @param {Function} [callback] - Response callback that will be called
+     *   with one data argument.
      */
     request(action, data, callback) {
       let request = document.createTextNode('');
diff --git a/web/interfaces.js b/web/interfaces.js
index bb22e0bed..a8780f9ba 100644
--- a/web/interfaces.js
+++ b/web/interfaces.js
@@ -156,8 +156,8 @@ class IPDFAnnotationLayerFactory {
   /**
    * @param {HTMLDivElement} pageDiv
    * @param {PDFPage} pdfPage
-   * @param {string} imageResourcesPath - (optional) Path for image resources,
-   *   mainly for annotation icons. Include trailing slash.
+   * @param {string} [imageResourcesPath] - Path for image resources, mainly
+   *   for annotation icons. Include trailing slash.
    * @param {boolean} renderInteractiveForms
    * @param {IL10n} l10n
    * @returns {AnnotationLayerBuilder}
diff --git a/web/overlay_manager.js b/web/overlay_manager.js
index 461244076..2a7688f99 100644
--- a/web/overlay_manager.js
+++ b/web/overlay_manager.js
@@ -27,13 +27,13 @@ class OverlayManager {
   /**
    * @param {string} name - The name of the overlay that is registered.
    * @param {HTMLDivElement} element - The overlay's DOM element.
-   * @param {function} callerCloseMethod - (optional) The method that, if
-   *                   present, calls `OverlayManager.close` from the object
-   *                   registering the overlay. Access to this method is
-   *                   necessary in order to run cleanup code when e.g.
-   *                   the overlay is force closed. The default is `null`.
-   * @param {boolean} canForceClose - (optional) Indicates if opening the
-   *                  overlay closes an active overlay. The default is `false`.
+   * @param {function} [callerCloseMethod] - The method that, if present, calls
+   *                   `OverlayManager.close` from the object registering the
+   *                   overlay. Access to this method is necessary in order to
+   *                   run cleanup code when e.g. the overlay is force closed.
+   *                   The default is `null`.
+   * @param {boolean} [canForceClose] - Indicates if opening the overlay closes
+   *                  an active overlay. The default is `false`.
    * @returns {Promise} A promise that is resolved when the overlay has been
    *                    registered.
    */
diff --git a/web/pdf_cursor_tools.js b/web/pdf_cursor_tools.js
index 252963944..d7965aca0 100644
--- a/web/pdf_cursor_tools.js
+++ b/web/pdf_cursor_tools.js
@@ -25,9 +25,9 @@ const CursorTool = {
  * @typedef {Object} PDFCursorToolsOptions
  * @property {HTMLDivElement} container - The document container.
  * @property {EventBus} eventBus - The application event bus.
- * @property {number} cursorToolOnLoad - (optional) The cursor tool that will be
- *   enabled on load; the constants from {CursorTool} should be used.
- *   The default value is `CursorTool.SELECT`.
+ * @property {number} [cursorToolOnLoad] - The cursor tool that will be enabled
+ *   on load; the constants from {CursorTool} should be used. The default value
+ *   is `CursorTool.SELECT`.
  */
 
 class PDFCursorTools {
diff --git a/web/pdf_history.js b/web/pdf_history.js
index c94aa3b19..74042ba39 100644
--- a/web/pdf_history.js
+++ b/web/pdf_history.js
@@ -33,15 +33,15 @@ const UPDATE_VIEWAREA_TIMEOUT = 1000; // milliseconds
 /**
  * @typedef {Object} InitializeParameters
  * @property {string} fingerprint - The PDF document's unique fingerprint.
- * @property {boolean} resetHistory - (optional) Reset the browsing history.
- * @property {boolean} updateUrl - (optional) Attempt to update the document
- *   URL, with the current hash, when pushing/replacing browser history entries.
+ * @property {boolean} [resetHistory] - Reset the browsing history.
+ * @property {boolean} [updateUrl] - Attempt to update the document URL, with
+ *   the current hash, when pushing/replacing browser history entries.
  */
 
 /**
  * @typedef {Object} PushParameters
- * @property {string} namedDest - (optional) The named destination. If absent,
- *   a stringified version of `explicitDest` is used.
+ * @property {string} [namedDest] - The named destination. If absent, a
+ *   stringified version of `explicitDest` is used.
  * @property {Array} explicitDest - The explicit destination array.
  * @property {number} pageNumber - The page to which the destination points.
  */
diff --git a/web/pdf_link_service.js b/web/pdf_link_service.js
index 42bfb9f99..a34c4fe71 100644
--- a/web/pdf_link_service.js
+++ b/web/pdf_link_service.js
@@ -18,11 +18,11 @@ import { getGlobalEventBus, parseQueryString } from './ui_utils';
 /**
  * @typedef {Object} PDFLinkServiceOptions
  * @property {EventBus} eventBus - The application event bus.
- * @property {number} externalLinkTarget - (optional) Specifies the `target`
- *   attribute for external links. Must use one of the values from {LinkTarget}.
+ * @property {number} [externalLinkTarget] - Specifies the `target` attribute
+ *   for external links. Must use one of the values from {LinkTarget}.
  *   Defaults to using no target.
- * @property {string} externalLinkRel - (optional) Specifies the `rel` attribute
- *   for external links. Defaults to stripping the referrer.
+ * @property {string} [externalLinkRel] - Specifies the `rel` attribute for
+ *   external links. Defaults to stripping the referrer.
  */
 
 /**
diff --git a/web/pdf_page_view.js b/web/pdf_page_view.js
index 8f13a608d..c1bdef65e 100644
--- a/web/pdf_page_view.js
+++ b/web/pdf_page_view.js
@@ -32,23 +32,23 @@ import { viewerCompatibilityParams } from './viewer_compatibility';
  * @property {PageViewport} defaultViewport - The page viewport.
  * @property {PDFRenderingQueue} renderingQueue - The rendering queue object.
  * @property {IPDFTextLayerFactory} textLayerFactory
- * @property {number} textLayerMode - (optional) Controls if the text layer used
- *   for selection and searching is created, and if the improved text selection
+ * @property {number} [textLayerMode] - Controls if the text layer used for
+ *   selection and searching is created, and if the improved text selection
  *   behaviour is enabled. The constants from {TextLayerMode} should be used.
  *   The default value is `TextLayerMode.ENABLE`.
  * @property {IPDFAnnotationLayerFactory} annotationLayerFactory
- * @property {string} imageResourcesPath - (optional) Path for image resources,
- *   mainly for annotation icons. Include trailing slash.
+ * @property {string} [imageResourcesPath] - Path for image resources, mainly
+ *   for annotation icons. Include trailing slash.
  * @property {boolean} renderInteractiveForms - Turns on rendering of
  *   interactive form elements. The default is `false`.
  * @property {string} renderer - 'canvas' or 'svg'. The default is 'canvas'.
- * @property {boolean} enableWebGL - (optional) Enables WebGL accelerated
- *   rendering for some operations. The default value is `false`.
- * @property {boolean} useOnlyCssZoom - (optional) Enables CSS only zooming.
- *   The default value is `false`.
- * @property {number} maxCanvasPixels - (optional) The maximum supported canvas
- *   size in total pixels, i.e. width * height. Use -1 for no limit.
- *   The default value is 4096 * 4096 (16 mega-pixels).
+ * @property {boolean} [enableWebGL] - Enables WebGL accelerated rendering for
+ *   some operations. The default value is `false`.
+ * @property {boolean} [useOnlyCssZoom] - Enables CSS only zooming. The default
+ *   value is `false`.
+ * @property {number} [maxCanvasPixels] - The maximum supported canvas size in
+ *   total pixels, i.e. width * height. Use -1 for no limit. The default value
+ *   is 4096 * 4096 (16 mega-pixels).
  * @property {IL10n} l10n - Localization service.
  */
 
diff --git a/web/pdf_presentation_mode.js b/web/pdf_presentation_mode.js
index 93eedb2bf..bea6a3a13 100644
--- a/web/pdf_presentation_mode.js
+++ b/web/pdf_presentation_mode.js
@@ -32,11 +32,11 @@ const SWIPE_ANGLE_THRESHOLD = Math.PI / 6;
 /**
  * @typedef {Object} PDFPresentationModeOptions
  * @property {HTMLDivElement} container - The container for the viewer element.
- * @property {HTMLDivElement} viewer - (optional) The viewer element.
+ * @property {HTMLDivElement} [viewer] - The viewer element.
  * @property {PDFViewer} pdfViewer - The document viewer.
  * @property {EventBus} eventBus - The application event bus.
- * @property {Array} contextMenuItems - (optional) The menu items that are added
- *   to the context menu in Presentation Mode.
+ * @property {Array} [contextMenuItems] - The menu items that are added to the
+ *   context menu in Presentation Mode.
  */
 
 class PDFPresentationMode {
diff --git a/web/pdf_sidebar.js b/web/pdf_sidebar.js
index 5b39cf5bf..3cb72907d 100644
--- a/web/pdf_sidebar.js
+++ b/web/pdf_sidebar.js
@@ -34,8 +34,8 @@ const SidebarView = {
  * @property {PDFThumbnailViewer} pdfThumbnailViewer - The thumbnail viewer.
  * @property {EventBus} eventBus - The application event bus.
  * @property {IL10n} l10n - The localization service.
- * @property {boolean} disableNotification - (optional) Disable the notification
- *   for documents containing outline/attachments. The default value is `false`.
+ * @property {boolean} [disableNotification] - Disable the notification for
+ *   documents containing outline/attachments. The default value is `false`.
  */
 
 /**
@@ -153,8 +153,8 @@ class PDFSidebar {
   /**
    * @param {number} view - The sidebar view that should be switched to,
    *                        must be one of the values in {SidebarView}.
-   * @param {boolean} forceOpen - (optional) Ensure that the sidebar is open.
-   *                              The default value is `false`.
+   * @param {boolean} [forceOpen] - Ensure that the sidebar is open.
+   *                                The default value is `false`.
    */
   switchView(view, forceOpen = false) {
     this._switchView(view, forceOpen);
diff --git a/web/pdf_thumbnail_view.js b/web/pdf_thumbnail_view.js
index 601ecad7a..6f7c8b486 100644
--- a/web/pdf_thumbnail_view.js
+++ b/web/pdf_thumbnail_view.js
@@ -30,9 +30,9 @@ const THUMBNAIL_WIDTH = 98; // px
  * @property {PageViewport} defaultViewport - The page viewport.
  * @property {IPDFLinkService} linkService - The navigation/linking service.
  * @property {PDFRenderingQueue} renderingQueue - The rendering queue object.
- * @property {boolean} disableCanvasToImageConversion - (optional) Don't convert
- *   the canvas thumbnails to images. This prevents `toDataURL` calls,
- *   but increases the overall memory usage. The default value is `false`.
+ * @property {boolean} [disableCanvasToImageConversion] - Don't convert the
+ *   canvas thumbnails to images. This prevents `toDataURL` calls, but
+ *   increases the overall memory usage. The default value is `false`.
  * @property {IL10n} l10n - Localization service.
  */
 
diff --git a/web/text_layer_builder.js b/web/text_layer_builder.js
index 6a59e5527..096b3f120 100644
--- a/web/text_layer_builder.js
+++ b/web/text_layer_builder.js
@@ -79,8 +79,8 @@ class TextLayerBuilder {
   /**
    * Renders the text layer.
    *
-   * @param {number} timeout - (optional) wait for a specified amount of
-   *                           milliseconds before rendering
+   * @param {number} [timeout] - Wait for a specified amount of milliseconds
+   *                             before rendering.
    */
   render(timeout = 0) {
     if (!(this.textContent || this.textContentStream) || this.renderingDone) {