add task solution

src/transformState.js

@@ -4,8 +4,39 @@
  * @param {Object} state
  * @param {Object[]} actions
  */
+const ADD_PROPERTIES = 'addProperties';
+const REMOVE_PROPERTIES = 'removeProperties';
+const CLEAR_ALL = 'clear';
+
 function transformState(state, actions) {
-  // write code here
+  const stateHistory = [];
+
+  for (const order of actions) {
+    switch (order.type) {
+      case ADD_PROPERTIES:
+        Object.assign(state, order.extraData);
+        stateHistory.push(Object.assign({}, state));
+        break;
+
+      case REMOVE_PROPERTIES:
+        for (const remove of order.keysToRemove) {
+          delete state[remove];
+        }
+
+        stateHistory.push(Object.assign({}, state));
+        break;
+
+      case CLEAR_ALL:
+        for (const key in state) {
+          delete state[key];
+        }
+
+        stateHistory.push(Object.assign({}, state));
+        break;
+    }
+  }
+
+  return state;
 }
 
 module.exports = transformState;