Add comments to explain global exposing code

Author: jonathanKingston

injected/src/trackers.js

@@ -4,6 +4,9 @@ import { getGlobal } from './utils.js';
  * Check if the current document origin is on the tracker list, using the provided lookup trie.
  * @param {object} trackerLookup Trie lookup of tracker domains
  * @returns {boolean} True iff the origin is a tracker.
+ *
+ * Note: getGlobal() is in testing to get the global object,
+ * it's a work around for ESM modules are essentially singletons preventing overriding of global variables.
  */
 export function isTrackerOrigin(trackerLookup, originHostname = getGlobal().document.location.hostname) {
     const parts = originHostname.split('.').reverse();

injected/src/utils.js

@@ -49,6 +49,10 @@ export function setGlobal(globalObjIn) {
     Error = globalObj.Error;
 }
 
+/**
+ * Used for testing to allow other files to override the globals used within this file.
+ * @returns {globalThis} the global object
+ */
 export function getGlobal() {
     return globalObj;
 }