diff --git a/src/features/TodolistsList/tasks-reducer.ts b/src/features/TodolistsList/tasks-reducer.ts
index 6a376f9..a7e1faf 100644
--- a/src/features/TodolistsList/tasks-reducer.ts
+++ b/src/features/TodolistsList/tasks-reducer.ts
@@ -44,21 +44,13 @@ const tasksSlice = createSlice({
         todolistId: string
       }>
     ) {
-      return {
-        ...state,
-        [action.payload.todolistId]: state[action.payload.todolistId].filter(
-          (t) => t.id != action.payload.taskId
-        ),
-      }
+      const tasks = state[action.payload.todolistId]
+      const index = tasks.findIndex((task) => task.id === action.payload.taskId)
+      if (index !== -1) tasks.splice(index, 1)
     },
     addTask(state, action: PayloadAction<TaskEntity>) {
-      return {
-        ...state,
-        [action.payload.todoListId]: [
-          action.payload,
-          ...state[action.payload.todoListId],
-        ],
-      }
+      const tasks = state[action.payload.todoListId]
+      tasks.unshift(action.payload)
     },
     updateTask(
       state,
@@ -68,14 +60,10 @@ const tasksSlice = createSlice({
         todolistId: string
       }>
     ) {
-      return {
-        ...state,
-        [action.payload.todolistId]: state[action.payload.todolistId].map(
-          (t) =>
-            t.id === action.payload.taskId
-              ? { ...t, ...action.payload.model }
-              : t
-        ),
+      const tasks = state[action.payload.todolistId]
+      const task = tasks.find((task) => task.id === action.payload.taskId)
+      if (task) {
+        Object.assign(task, action.payload.model)
       }
     },
     setTasks(
@@ -85,25 +73,21 @@ const tasksSlice = createSlice({
         todolistId: string
       }>
     ) {
-      return { ...state, [action.payload.todolistId]: action.payload.tasks }
+      state[action.payload.todolistId] = action.payload.tasks
     },
   },
   extraReducers(builder) {
     builder
       .addCase(addTodolist, (state, action) => {
-        return { ...state, [action.payload.id]: [] }
+        state[action.payload.id] = []
       })
       .addCase(removeTodolist, (state, action) => {
-        const copyState = { ...state }
-        delete copyState[action.payload]
-        return copyState
+        delete state[action.payload]
       })
       .addCase(setTodolists, (state, action) => {
-        const copyState = { ...state }
         action.payload.forEach((tl) => {
-          copyState[tl.id] = []
+          state[tl.id] = []
         })
-        return copyState
       })
   },
 })