diff --git a/src/transformState.js b/src/transformState.js
index a1eaa0640..4171e96f3 100644
--- a/src/transformState.js
+++ b/src/transformState.js
@@ -5,7 +5,29 @@
  * @param {Object[]} actions
  */
 function transformState(state, actions) {
-  // write code here
+  for (const action of actions) {
+    const { type, extraData, keysToRemove } = action;
+
+    switch (type) {
+      case 'addProperties':
+        for (const key in extraData) {
+          state[key] = extraData[key];
+        }
+        break;
+      case 'removeProperties':
+        for (const key of keysToRemove) {
+          delete state[key];
+        }
+        break;
+      case 'clear':
+        for (const key in state) {
+          delete state[key];
+        }
+        break;
+      default:
+        throw new Error('Bad action type');
+    }
+  }
 }
 
 module.exports = transformState;