[api-minor] Move the ReadableStream polyfill to the global scope

.eslintrc

@@ -117,12 +117,6 @@
     "no-catch-shadow": "error",
     "no-delete-var": "error",
     "no-label-var": "error",
-    "no-restricted-globals": ["error",
-      {
-        "name": "ReadableStream",
-        "message": "Import it from `src/shared/util.js` or `pdfjsLib` instead; outside of the `/src` and `/web` folders, the rule may be disabled as needed. ",
-      },
-    ],
     "no-shadow-restricted-names": "error",
     "no-shadow": "off",
     "no-undef-init": "error",

src/display/display_utils.js

@@ -435,7 +435,6 @@ class StatTimer {
 function isFetchSupported() {
   return (typeof fetch !== 'undefined' &&
           typeof Response !== 'undefined' && 'body' in Response.prototype &&
-          // eslint-disable-next-line no-restricted-globals
           typeof ReadableStream !== 'undefined');
 }
 

src/pdf.js

@@ -106,7 +106,6 @@ exports.createObjectURL = pdfjsSharedUtil.createObjectURL;
 exports.removeNullCharacters = pdfjsSharedUtil.removeNullCharacters;
 exports.shadow = pdfjsSharedUtil.shadow;
 exports.Util = pdfjsSharedUtil.Util;
-exports.ReadableStream = pdfjsSharedUtil.ReadableStream;
 exports.RenderingCancelledException =
   pdfjsDisplayDisplayUtils.RenderingCancelledException;
 exports.getFilenameFromUrl = pdfjsDisplayDisplayUtils.getFilenameFromUrl;

src/shared/compatibility.js

@@ -249,6 +249,36 @@ const isIE = /Trident/.test(userAgent);
   globalThis.URL = require('core-js/web/url');
 })();
 
+// Support: IE, Node.js
+(function checkReadableStream() {
+  if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('IMAGE_DECODERS')) {
+    // The current image decoders are synchronous, hence `ReadableStream`
+    // shouldn't need to be polyfilled for the IMAGE_DECODERS build target.
+    return;
+  }
+  let isReadableStreamSupported = false;
+
+  if (typeof ReadableStream !== 'undefined') {
+    // MS Edge may say it has ReadableStream but they are not up to spec yet.
+    try {
+      // eslint-disable-next-line no-new
+      new ReadableStream({
+        start(controller) {
+          controller.close();
+        },
+      });
+      isReadableStreamSupported = true;
+    } catch (e) {
+      // The ReadableStream constructor cannot be used.
+    }
+  }
+  if (isReadableStreamSupported) {
+    return;
+  }
+  globalThis.ReadableStream =
+    require('web-streams-polyfill/dist/ponyfill').ReadableStream;
+})();
+
 // Support: IE<11, Safari<8, Chrome<36
 (function checkWeakMap() {
   if (globalThis.WeakMap) {

src/shared/message_handler.js

@@ -16,7 +16,7 @@
 
 import {
   AbortException, assert, createPromiseCapability, MissingPDFException,
-  ReadableStream, UnexpectedResponseException, UnknownErrorException
+  UnexpectedResponseException, UnknownErrorException
 } from './util';
 
 const CallbackKind = {

src/shared/util.js

@@ -15,7 +15,6 @@
 /* eslint no-var: error */
 
 import './compatibility';
-import { ReadableStream } from './streams_polyfill';
 
 const IDENTITY_MATRIX = [1, 0, 0, 1, 0, 0];
 const FONT_IDENTITY_MATRIX = [0.001, 0, 0, 0.001, 0, 0];
@@ -930,7 +929,6 @@ export {
   readUint16,
   readUint32,
   removeNullCharacters,
-  ReadableStream,
   setVerbosityLevel,
   shadow,
   string32,

test/unit/util_spec.js

@@ -16,8 +16,7 @@
 import {
   bytesToString, createPromiseCapability, createValidAbsoluteUrl, isArrayBuffer,
   isBool, isEmptyObj, isNum, isSameOrigin, isSpace, isString, log2,
-  ReadableStream, removeNullCharacters, string32, stringToBytes,
-  stringToPDFString
+  removeNullCharacters, string32, stringToBytes, stringToPDFString
 } from '../../src/shared/util';
 
 describe('util', function() {