Some hasJSActions, and general annotation-code, related cleanup in the viewer and API

- Add support for logical assignment operators, i.e. `&&=`, `||=`, and `??=`, with a Babel-plugin. Given that these required incrementing the ECMAScript version in the ESLint and Acorn configurations, and that platform/browser support is still fairly limited, always transpiling them seems appropriate for now.

 - Cache the `hasJSActions` promise in the API, similar to the existing `getAnnotations` caching. With this implemented, the lookup should now be cheap enough that it can be called unconditionally in the viewer.

 - Slightly improve cleanup of resources when destroying the `WorkerTransport`.

 - Remove the `annotationStorage`-property from the `PDFPageView` constructor, since it's not necessary and also brings it more inline with the `BaseViewer`.

 - Update the `BaseViewer.createAnnotationLayerBuilder` method to actaually agree with the `IPDFAnnotationLayerFactory` interface.[1]

 - Slightly tweak a couple of JSDoc comments.

---
[1] We probably ought to re-factor both the `IPDFTextLayerFactory` and `IPDFAnnotationLayerFactory` interfaces to take parameter objects instead, since especially the `IPDFAnnotationLayerFactory` one is becoming quite unwieldy. Given that that would likely be a breaking change for any custom viewer-components implementation, this probably requires careful deprecation.

.eslintrc

@@ -1,6 +1,6 @@
 {
   "parserOptions": {
-    "ecmaVersion": 2020,
+    "ecmaVersion": 2021,
     "sourceType": "module",
   },
 

external/builder/preprocessor2.js

@@ -8,7 +8,7 @@ var path = require("path");
 
 var PDFJS_PREPROCESSOR_NAME = "PDFJSDev";
 var ROOT_PREFIX = "$ROOT/";
-const ACORN_ECMA_VERSION = 2020;
+const ACORN_ECMA_VERSION = 2021;
 
 function isLiteral(obj, value) {
   return obj.type === "Literal" && obj.value === value;

gulpfile.js

@@ -226,6 +226,7 @@ function createWebpackConfig(defines, output) {
           options: {
             presets: skipBabel ? undefined : ["@babel/preset-env"],
             plugins: [
+              "@babel/plugin-proposal-logical-assignment-operators",
               "@babel/plugin-transform-modules-commonjs",
               [
                 "@babel/plugin-transform-runtime",
@@ -570,6 +571,7 @@ gulp.task("default_preferences-pre", function () {
       sourceType: "module",
       presets: undefined, // SKIP_BABEL
       plugins: [
+        "@babel/plugin-proposal-logical-assignment-operators",
         "@babel/plugin-transform-modules-commonjs",
         babelPluginReplaceNonWebPackRequire,
       ],
@@ -1234,6 +1236,7 @@ function buildLib(defines, dir) {
       sourceType: "module",
       presets: skipBabel ? undefined : ["@babel/preset-env"],
       plugins: [
+        "@babel/plugin-proposal-logical-assignment-operators",
         "@babel/plugin-transform-modules-commonjs",
         [
           "@babel/plugin-transform-runtime",

package.json

@@ -3,6 +3,7 @@
   "version": "2.0.0",
   "devDependencies": {
     "@babel/core": "^7.12.3",
+    "@babel/plugin-proposal-logical-assignment-operators": "^7.12.1",
     "@babel/plugin-transform-modules-commonjs": "^7.12.1",
     "@babel/plugin-transform-runtime": "^7.12.1",
     "@babel/preset-env": "^7.12.1",

src/display/api.js

@@ -905,7 +905,7 @@ class PDFDocumentProxy {
 
   /**
    * @returns {Promise<boolean>} A promise that is resolved with `true`
-   * if some /AcroForm fields have JavaScript actions.
+   *   if some /AcroForm fields have JavaScript actions.
    */
   hasJSActions() {
     return this._transport.hasJSActions();
@@ -2128,7 +2128,10 @@ class WorkerTransport {
     const terminated = this.messageHandler.sendWithPromise("Terminate", null);
     waitOn.push(terminated);
     Promise.all(waitOn).then(() => {
+      this.commonObjs.clear();
       this.fontLoader.clear();
+      this._hasJSActionsPromise = null;
+
       if (this._networkStream) {
         this._networkStream.cancelAllRequests(
           new AbortException("Worker was terminated.")
@@ -2577,7 +2580,10 @@ class WorkerTransport {
   }
 
   hasJSActions() {
-    return this.messageHandler.sendWithPromise("HasJSActions", null);
+    return (this._hasJSActionsPromise ||= this.messageHandler.sendWithPromise(
+      "HasJSActions",
+      null
+    ));
   }
 
   getCalculationOrderIds() {
@@ -2679,6 +2685,7 @@ class WorkerTransport {
       }
       this.commonObjs.clear();
       this.fontLoader.clear();
+      this._hasJSActionsPromise = null;
     });
   }
 

web/annotation_layer_builder.js

@@ -137,8 +137,8 @@ class DefaultAnnotationLayerFactory {
    *   for annotation icons. Include trailing slash.
    * @param {boolean} renderInteractiveForms
    * @param {IL10n} l10n
-   * @param {boolean} enableScripting
-   * @param {Promise<boolean>} hasJSActionsPromise
+   * @param {boolean} [enableScripting]
+   * @param {Promise<boolean>} [hasJSActionsPromise]
    * @returns {AnnotationLayerBuilder}
    */
   createAnnotationLayerBuilder(

web/base_viewer.js

@@ -469,8 +469,7 @@ class BaseViewer {
     }
     const pagesCount = pdfDocument.numPages;
     const firstPagePromise = pdfDocument.getPage(1);
-
-    const annotationStorage = pdfDocument.annotationStorage;
+    // Rendering (potentially) depends on this, hence fetching it immediately.
     const optionalContentConfigPromise = pdfDocument.getOptionalContentConfig();
 
     this._pagesCapability.promise.then(() => {
@@ -521,7 +520,6 @@ class BaseViewer {
             id: pageNum,
             scale,
             defaultViewport: viewport.clone(),
-            annotationStorage,
             optionalContentConfigPromise,
             renderingQueue: this.renderingQueue,
             textLayerFactory,
@@ -1244,11 +1242,14 @@ class BaseViewer {
   /**
    * @param {HTMLDivElement} pageDiv
    * @param {PDFPage} pdfPage
+   * @param {AnnotationStorage} [annotationStorage] - Storage for annotation
+   *   data in forms.
    * @param {string} [imageResourcesPath] - Path for image resources, mainly
    *   for annotation icons. Include trailing slash.
    * @param {boolean} renderInteractiveForms
    * @param {IL10n} l10n
    * @param {boolean} [enableScripting]
+   * @param {Promise<boolean>} [hasJSActionsPromise]
    * @returns {AnnotationLayerBuilder}
    */
   createAnnotationLayerBuilder(
@@ -1258,21 +1259,22 @@ class BaseViewer {
     imageResourcesPath = "",
     renderInteractiveForms = false,
     l10n = NullL10n,
-    enableScripting = false
+    enableScripting = false,
+    hasJSActionsPromise = null
   ) {
     return new AnnotationLayerBuilder({
       pageDiv,
       pdfPage,
-      annotationStorage,
+      annotationStorage:
+        annotationStorage || this.pdfDocument?.annotationStorage,
       imageResourcesPath,
       renderInteractiveForms,
       linkService: this.linkService,
       downloadManager: this.downloadManager,
       l10n,
       enableScripting,
-      hasJSActionsPromise: enableScripting
-        ? this.pdfDocument.hasJSActions()
-        : Promise.resolve(false),
+      hasJSActionsPromise:
+        hasJSActionsPromise || this.pdfDocument?.hasJSActions(),
     });
   }
 

web/pdf_page_view.js

@@ -38,8 +38,6 @@ import { viewerCompatibilityParams } from "./viewer_compatibility.js";
  * @property {number} id - The page unique ID (normally its number).
  * @property {number} scale - The page scale display.
  * @property {PageViewport} defaultViewport - The page viewport.
- * @property {AnnotationStorage} [annotationStorage] - Storage for annotation
- *   data in forms. The default value is `null`.
  * @property {Promise<OptionalContentConfig>} [optionalContentConfigPromise] -
  *   A promise that is resolved with an {@link OptionalContentConfig} instance.
  *   The default value is `null`.
@@ -89,7 +87,6 @@ class PDFPageView {
     this.scale = options.scale || DEFAULT_SCALE;
     this.viewport = defaultViewport;
     this.pdfPageRotate = defaultViewport.rotation;
-    this._annotationStorage = options.annotationStorage || null;
     this._optionalContentConfigPromise =
       options.optionalContentConfigPromise || null;
     this.hasRestrictedScaling = false;
@@ -549,11 +546,12 @@ class PDFPageView {
         this.annotationLayer = this.annotationLayerFactory.createAnnotationLayerBuilder(
           div,
           pdfPage,
-          this._annotationStorage,
+          /* annotationStorage = */ null,
           this.imageResourcesPath,
           this.renderInteractiveForms,
           this.l10n,
-          this.enableScripting
+          this.enableScripting,
+          /* hasJSActionsPromise = */ null
         );
       }
       this._renderAnnotationLayer();