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/Modifier/utils.js

@@ -0,0 +1,26 @@
+import { getBonusTypes } from './accessors';
+/**
+ *
+ * @param modifiers
+ * @param modifierBonusType
+ */
+export function countModifierBonusTypes(modifiers, modifierBonusType) {
+    let count = 0;
+    for (let i = 0; i < modifiers.length; i++) {
+        const modifier = modifiers[i];
+        const modifierBonusTypes = getBonusTypes(modifier);
+        if (modifierBonusTypes && modifierBonusTypes.includes(modifierBonusType)) {
+            count += 1;
+        }
+    }
+    return count;
+}
+/**
+ *
+ * @param modifiers
+ * @param filter
+ * @param filterArgs
+ */
+export function filterModifiers(modifiers, filter, filterArgs = []) {
+    return modifiers.filter((modifier) => filter(modifier, ...filterArgs));
+}