fix(core): Case insensitive MIME type comparison

modules/core/src/lib/api/select-loader.ts

@@ -7,6 +7,7 @@ import {compareArrayBuffers, path} from '@loaders.gl/loader-utils';
 import {normalizeLoader} from '../loader-utils/normalize-loader';
 import {log} from '../utils/log';
 import {getResourceUrl, getResourceMIMEType} from '../utils/resource-utils';
+import {compareMIMETypes} from '../utils/mime-type-utils';
 import {getRegisteredLoaders} from './register-loaders';
 import {isBlob} from '../../javascript-utils/is-type';
 import {stripQueryString} from '../utils/url-utils';
@@ -216,13 +217,13 @@ function findLoaderByExtension(loaders: Loader[], extension: string): Loader | n
 
 function findLoaderByMIMEType(loaders: Loader[], mimeType: string): Loader | null {
   for (const loader of loaders) {
-    if (loader.mimeTypes && loader.mimeTypes.includes(mimeType)) {
+    if (loader.mimeTypes?.some((mimeType1) => compareMIMETypes(mimeType, mimeType1))) {
       return loader;
     }
 
     // Support referring to loaders using the "unregistered tree"
     // https://en.wikipedia.org/wiki/Media_type#Unregistered_tree
-    if (mimeType === `application/x.${loader.id}`) {
+    if (compareMIMETypes(mimeType, `application/x.${loader.id}`)) {
       return loader;
     }
   }

modules/core/src/lib/utils/mime-type-utils.ts

@@ -8,6 +8,20 @@
 const DATA_URL_PATTERN = /^data:([-\w.]+\/[-\w.+]+)(;|,)/;
 const MIME_TYPE_PATTERN = /^([-\w.]+\/[-\w.+]+)/;
 
+/**
+ * Compare two MIME types, case insensitively etc.
+ * @param mimeType1
+ * @param mimeType2
+ * @returns true if the MIME types are equivalent
+ * @see https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types#structure_of_a_mime_type
+ */
+export function compareMIMETypes(mimeType1: string, mimeType2: string): boolean {
+  if (mimeType1.toLowerCase() === mimeType2.toLowerCase()) {
+    return true;
+  }
+  return false;
+}
+
 /**
  * Remove extra data like `charset` from MIME types
  * @param mimeString

modules/core/test/lib/utils/mime-type-utils.spec.ts

@@ -4,10 +4,18 @@
 
 import test from 'tape-promise/tape';
 import {parseMIMEType, parseMIMETypeFromURL} from '@loaders.gl/core/lib/utils/mime-type-utils';
+import {compareMIMETypes} from '@loaders.gl/core/lib/utils/mime-type-utils';
 
 const DATA_URL =
   'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACAQMAAABIeJ9nAAAABGdBTUEAALGPC/xhBQAAAAFzUkdCAK7OHOkAAAAGUExURf///wAAAFXC034AAAAMSURBVAjXY3BgaAAAAUQAwetZAwkAAAAASUVORK5CYII=';
 
+test('compareMIMETypes', (t) => {
+  t.equal(compareMIMETypes('image/png', 'image/jpeg'), false);
+  t.equal(compareMIMETypes('image/png', 'image/png'), true);
+  t.equal(compareMIMETypes('image/png', 'image/PNG'), true);
+  t.end();
+});
+
 test('parseMIMEType', (t) => {
   t.equal(parseMIMEType('image/png;'), 'image/png');
   t.equal(parseMIMEType('image/png'), 'image/png');