refactoring

docs/SymptomsCausedByCOVIDLots/js/DictUtils.js

@@ -0,0 +1,28 @@
+class DictUtils {
+
+    static retainCommonKeys({ dict1, dict2 }) {
+        const commonKeys = DictUtils.#getCommonKeys(dict1, dict2);
+        return {
+            dict1: DictUtils.#retainKeysOfDict(dict1, commonKeys),
+            dict2: DictUtils.#retainKeysOfDict(dict2, commonKeys)
+        };
+    }
+
+    static #getCommonKeys(dict1, dict2) {
+        return Sets.intersection(
+            DictUtils.#getKeySet(dict1),
+            DictUtils.#getKeySet(dict2));
+    }
+
+    static #getKeySet(dict) {
+        return new Set(Object.keys(dict));
+    }
+
+    static #retainKeysOfDict(dict, keys2Retain) {
+        const entries2Retain =
+            Object
+                .entries(dict)
+                .filter(([key, _]) => keys2Retain.has(key));
+        return Object.fromEntries(entries2Retain);
+    }
+}