made changes

src/transformState.js

@@ -5,27 +5,21 @@
  * @param {Object[]} actions
  */
 function transformState(state, action) {
+  const CLEAR = 'clear';
+
   for (const obj of action) {
-    // to iterate all objects in array.
     for (const [key, value] of Object.entries(obj)) {
-      // to iterate every object and split on keys and values.
-      //
-      // conditions check
-      if (obj[key] === obj.type && value === 'clear') {
+      if (obj[key] === obj.type && value === CLEAR) {
         for (const ke of Object.keys(state)) {
           delete state[ke];
         }
       }
 
       if (obj[key] === obj.extraData) {
-        // add key and value to the object
-        for (const [k, v] of Object.entries(obj[key])) {
-          state[k] = v;
-        }
+        Object.assign(state, obj.extraData);
       }
 
       if (obj[key] === obj.keysToRemove) {
-        // delete properies
         for (const k of obj[key]) {
           delete state[k];
         }