Fix #17: isImageBitmapSource() fails in web workers

Author: undecaf

README.md

@@ -59,7 +59,7 @@ Expose the `BarcodeDetectorPolyfill` API in variable `barcodeDetectorPolyfill`:
 
 ```html
 <script src="https://cdn.jsdelivr.net/npm/@undecaf/[email protected]/dist/index.js"></script>
-<script src="https://cdn.jsdelivr.net/npm/@undecaf/[email protected].20/dist/index.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/@undecaf/[email protected].21/dist/index.js"></script>
 <script>
     try {
         window['BarcodeDetector'].getSupportedFormats()

docs/example-bundled/js/main.js

@@ -1,6 +1,6 @@
 {
   "name": "@undecaf/barcode-detector-polyfill-example",
-  "version": "0.9.19",
+  "version": "0.9.21",
   "type": "module",
   "scripts": {
     "build:esbuild": "node esbuild.config.js",
@@ -9,7 +9,7 @@
   "author": "F. Kasper <[email protected]>",
   "license": "MIT",
   "dependencies": {
-    "@undecaf/barcode-detector-polyfill": "^0.9.20",
+    "@undecaf/barcode-detector-polyfill": "^0.9.21",
     "@undecaf/zbar-wasm": "^0.9.15"
   },
   "devDependencies": {

docs/example-loaded/js/main.js

@@ -1,6 +1,6 @@
 {
   "name": "@undecaf/barcode-detector-polyfill-example",
-  "version": "0.9.19",
+  "version": "0.9.21",
   "type": "module",
   "scripts": {
     "build:esbuild": "node esbuild.config.js",
@@ -9,7 +9,7 @@
   "author": "F. Kasper <[email protected]>",
   "license": "MIT",
   "dependencies": {
-    "@undecaf/barcode-detector-polyfill": "^0.9.20"
+    "@undecaf/barcode-detector-polyfill": "^0.9.21"
   },
   "devDependencies": {
     "@rollup/plugin-node-resolve": "^13.1.1",

example-bundled/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@undecaf/barcode-detector-polyfill",
-  "version": "0.9.20",
+  "version": "0.9.21",
   "description": "A WebAssembly polyfill for the Barcode Detection API",
   "keywords": [
     "polyfill",

example-loaded/package.json

@@ -230,13 +230,13 @@ export class BarcodeDetectorPolyfill {
      * object having zero width or height.
      */
     private static isImageBitmapSource(source: any): source is ImageBitmapSource {
-        return (source instanceof HTMLImageElement)
-            || (source instanceof HTMLVideoElement)
-            || (source instanceof HTMLCanvasElement)
-            || (source instanceof Blob)
+        return (typeof HTMLImageElement !== 'undefined' && source instanceof HTMLImageElement)
+            || (typeof HTMLVideoElement !== 'undefined' && source instanceof HTMLVideoElement)
+            || (typeof HTMLCanvasElement !== 'undefined' && source instanceof HTMLCanvasElement)
+            || (typeof CanvasRenderingContext2D !== 'undefined' && source instanceof CanvasRenderingContext2D)
+            || (typeof ImageBitmap !== 'undefined' && source instanceof ImageBitmap)
             || (source instanceof ImageData)
-            || (source instanceof CanvasRenderingContext2D)
-            || (source instanceof ImageBitmap)
+            || (source instanceof Blob)
             // Note the (lenient) equality operator
             || (source && source.width == 0)
             || (source && source.height == 0)