add IStorageManager and it's implementation via localStorage in LocalStorageManager

src/helpers/IStorageManager.ts

@@ -0,0 +1,7 @@
+interface IStorageManager<T> {
+    getItem(key: string): T | null;
+    setItem(key: string, value: T): void;
+    removeItem(key: string): void;
+}
+
+export default IStorageManager;

src/helpers/LocalStorageManager.ts

@@ -0,0 +1,20 @@
+import IStorageManager from "./IStorageManager.ts";
+
+class LocalStorageManager<T> implements IStorageManager<T> {
+    setItem = (key: string, value: T): void => {
+        localStorage.setItem(key, JSON.stringify(value));
+    }
+
+    getItem = (key: string): T | null => {
+        const value = localStorage.getItem(key);
+        if (value === null)
+            return value;
+        return JSON.parse(value);
+    }
+
+    removeItem = (key: string): void => {
+        localStorage.removeItem(key);
+    }
+}
+
+export default LocalStorageManager;