Grabbed dndbeyond's source code

```
~/go/bin/sourcemapper -output ddb -jsurl https://media.dndbeyond.com/character-app/static/js/main.90aa78c5.js
```

ddb_main/packages/rules-engine/es/engine/KnownInfusion/derivers.js

@@ -0,0 +1,14 @@
+import { DefinitionHacks } from '../Definition';
+import { getItemId, getItemTypeId } from './accessors';
+/**
+ *
+ * @param knownInfusionMapping
+ */
+export function deriveItemDefinitionKey(knownInfusionMapping) {
+    const itemTypeId = getItemTypeId(knownInfusionMapping);
+    const itemId = getItemId(knownInfusionMapping);
+    if (!itemTypeId || !itemId) {
+        return null;
+    }
+    return DefinitionHacks.hack__generateDefinitionKey(itemTypeId, itemId);
+}