diff --git a/README.md b/README.md
index d3c3756ab..b8fa3201e 100644
--- a/README.md
+++ b/README.md
@@ -47,4 +47,4 @@ Implement the ability to edit a todo title on double click:
 
 - Implement a solution following the [React task guideline](https://github.com/mate-academy/react_task-guideline#react-tasks-guideline).
 - Use the [React TypeScript cheat sheet](https://mate-academy.github.io/fe-program/js/extra/react-typescript).
-- Replace `<your_account>` with your Github username in the [DEMO LINK](https://<your_account>.github.io/react_todo-app-with-api/) and add it to the PR description.
+- Replace `<your_account>` with your Github username in the [DEMO LINK](https://v1rnt.github.io/react_todo-app-with-api/) and add it to the PR description.
diff --git a/src/App.tsx b/src/App.tsx
index 81e011f43..ce1ae14a5 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -1,26 +1,170 @@
-/* eslint-disable max-len */
-/* eslint-disable jsx-a11y/control-has-associated-label */
-import React from 'react';
-import { UserWarning } from './UserWarning';
+import React, { useCallback, useEffect, useMemo, useState } from 'react';
+import { deleteTodo, getTodos, patchTodo } from './api/todos';
 
-const USER_ID = 0;
+import { Todo } from './types/Todo';
+import { Filter } from './types/Filter';
+import { Errors } from './types/Errors';
+
+import { Footer } from './components/Footer';
+import { Header } from './components/Header';
+import { TodoList } from './components/TodoList';
+import { ErrorMessage } from './components/ErrorMessage';
+
+import { handleError } from './utils/handleError';
+import { getFilteredTodos } from './utils/getFilteredTodos';
 
 export const App: React.FC = () => {
-  if (!USER_ID) {
-    return <UserWarning />;
-  }
+  const [todosFromServer, setTodosFromServer] = useState<Todo[]>([]);
+  const [errorMessage, setErrorMessage] = useState<Errors>(Errors.Default);
+  const [filterOption, setFilterOption] = useState<Filter>(Filter.All);
+  const [tempTodo, setTempTodo] = useState<Todo | null>(null);
+  const [deletionIds, setDeletionIds] = useState<number[]>([]);
+  const [pendingTodos, setPendingTodos] = useState<Todo[]>([]);
+
+  const completedTodoIds = useMemo(() => {
+    return todosFromServer.filter(todo => todo.completed).map(todo => todo.id);
+  }, [todosFromServer]);
+
+  const uncompletedTodos = useMemo(() => {
+    return todosFromServer.filter(todo => !todo.completed);
+  }, [todosFromServer]);
+
+  const uncompletedTodosAmount = uncompletedTodos.length;
+
+  const filteredTodos = useMemo(() => {
+    return getFilteredTodos(todosFromServer, filterOption);
+  }, [todosFromServer, filterOption]);
+
+  const handleDeleteTodos = useCallback((ids: number[]) => {
+    Promise.all(
+      ids.map(id => {
+        setDeletionIds(current => [...current, id]);
+
+        deleteTodo(id)
+          .then(() => {
+            setTodosFromServer(current =>
+              current.filter(todo => todo.id !== id),
+            );
+          })
+          .catch(() => {
+            handleError(setErrorMessage, Errors.DeleteTodo);
+          })
+          .finally(() =>
+            setDeletionIds(currIds => currIds.filter(currId => currId !== id)),
+          );
+      }),
+    );
+  }, []);
+
+  const handleChangeTodos = useCallback(
+    (newTodos: Todo[]) => {
+      return Promise.all(
+        newTodos.map(todo => {
+          setPendingTodos(current => [...current, todo]);
+
+          const { id, ...todoBody } = todo;
+
+          return patchTodo(todoBody, id)
+            .then(() => {
+              setTodosFromServer(current =>
+                current.map(currentTodo => {
+                  return currentTodo.id !== todo.id ? currentTodo : todo;
+                }),
+              );
+            })
+            .catch(() => {
+              handleError(setErrorMessage, Errors.UpdateTodo);
+              throw new Error(errorMessage);
+            })
+            .finally(() => setPendingTodos([]));
+        }),
+      );
+    },
+    [errorMessage],
+  );
+
+  const handleToggleCompleted = (id: number, updatedField: Partial<Todo>) => {
+    setPendingTodos(current => [...current]);
+
+    return patchTodo(updatedField, id)
+      .then((updatedTodo: Todo) =>
+        setTodosFromServer(current =>
+          current.map(todo => (todo.id === id ? updatedTodo : todo)),
+        ),
+      )
+      .catch(() => {
+        handleError(setErrorMessage, Errors.UpdateTodo);
+        throw new Error(errorMessage);
+      })
+      .finally(() =>
+        setPendingTodos(current => current.filter(todo => todo.id !== id)),
+      );
+  };
+
+  const handleToggleCompletedAll = () => {
+    if (uncompletedTodos && uncompletedTodosAmount) {
+      Promise.allSettled(
+        uncompletedTodos.map(({ id }) =>
+          handleToggleCompleted(id, { completed: true }),
+        ),
+      );
+    } else {
+      Promise.allSettled(
+        todosFromServer.map(({ id }) =>
+          handleToggleCompleted(id, { completed: false }),
+        ),
+      );
+    }
+  };
+
+  useEffect(() => {
+    getTodos()
+      .then(setTodosFromServer)
+      .catch(() => handleError(setErrorMessage, Errors.LoadingTodos));
+  }, []);
 
   return (
-    <section className="section container">
-      <p className="title is-4">
-        Copy all you need from the prev task:
-        <br />
-        <a href="https://github.com/mate-academy/react_todo-app-add-and-delete#react-todo-app-add-and-delete">
-          React Todo App - Add and Delete
-        </a>
-      </p>
-
-      <p className="subtitle">Styles are already copied</p>
-    </section>
+    <div className="todoapp">
+      <h1 className="todoapp__title">todos</h1>
+
+      <div className="todoapp__content">
+        <Header
+          setTodos={setTodosFromServer}
+          setError={setErrorMessage}
+          setTempTodo={setTempTodo}
+          tempTodo={tempTodo}
+          uncompletedTodosAmount={uncompletedTodosAmount}
+          todos={todosFromServer}
+          onToggleCompletedAll={handleToggleCompletedAll}
+        />
+
+        {!!todosFromServer.length && (
+          <>
+            <TodoList
+              todos={filteredTodos}
+              tempTodo={tempTodo}
+              deletionIds={deletionIds}
+              pendingTodos={pendingTodos}
+              errorMessage={errorMessage}
+              onTodosChange={handleChangeTodos}
+              onDeleteTodos={handleDeleteTodos}
+            />
+            <Footer
+              filterOption={filterOption}
+              completedTodoIds={completedTodoIds}
+              uncompletedTodosAmount={uncompletedTodosAmount}
+              setFilterOption={setFilterOption}
+              setDeletionIds={setDeletionIds}
+              onDeleteTodos={handleDeleteTodos}
+            />
+          </>
+        )}
+      </div>
+
+      <ErrorMessage
+        errorMessage={errorMessage}
+        setErrorMessage={setErrorMessage}
+      />
+    </div>
   );
 };
diff --git a/src/api/todos.ts b/src/api/todos.ts
new file mode 100644
index 000000000..db01605f0
--- /dev/null
+++ b/src/api/todos.ts
@@ -0,0 +1,16 @@
+import { Todo } from '../types/Todo';
+import { client } from '../utils/fetchClient';
+
+export const USER_ID = 1606;
+
+export const getTodos = () => {
+  return client.get<Todo[]>(`/todos?userId=${USER_ID}`);
+};
+
+export const postTodo = (todo: Omit<Todo, 'id'>): Promise<Todo> =>
+  client.post<Todo>('/todos', todo);
+
+export const deleteTodo = (todoId: number) => client.delete(`/todos/${todoId}`);
+
+export const patchTodo = (props: Partial<Todo>, id: number): Promise<Todo> =>
+  client.patch<Todo>(`/todos/${id}`, props);
diff --git a/src/components/ErrorMessage/ErrorMessage.tsx b/src/components/ErrorMessage/ErrorMessage.tsx
new file mode 100644
index 000000000..727b7f64e
--- /dev/null
+++ b/src/components/ErrorMessage/ErrorMessage.tsx
@@ -0,0 +1,28 @@
+import { FC, Dispatch } from 'react';
+import cn from 'classnames';
+import { Errors } from '../../types/Errors';
+
+type Props = {
+  errorMessage: Errors;
+  setErrorMessage: Dispatch<React.SetStateAction<Errors>>;
+};
+
+export const ErrorMessage: FC<Props> = ({ errorMessage, setErrorMessage }) => {
+  return (
+    <div
+      data-cy="ErrorNotification"
+      // eslint-disable-next-line max-len
+      className={cn('notification is-danger is-light has-text-weight-normal', {
+        hidden: !errorMessage,
+      })}
+    >
+      <button
+        data-cy="HideErrorButton"
+        type="button"
+        className={cn('delete', { hidden: !errorMessage })}
+        onClick={() => setErrorMessage(Errors.Default)}
+      />
+      {errorMessage}
+    </div>
+  );
+};
diff --git a/src/components/ErrorMessage/index.ts b/src/components/ErrorMessage/index.ts
new file mode 100644
index 000000000..3dee9621e
--- /dev/null
+++ b/src/components/ErrorMessage/index.ts
@@ -0,0 +1 @@
+export * from './ErrorMessage';
diff --git a/src/components/Footer/Footer.tsx b/src/components/Footer/Footer.tsx
new file mode 100644
index 000000000..e0f245496
--- /dev/null
+++ b/src/components/Footer/Footer.tsx
@@ -0,0 +1,56 @@
+import { FC, Dispatch, SetStateAction } from 'react';
+import { Filter } from '../../types/Filter';
+import cn from 'classnames';
+
+type Props = {
+  completedTodoIds: number[];
+  uncompletedTodosAmount: number;
+  filterOption: Filter;
+  setFilterOption: Dispatch<SetStateAction<Filter>>;
+  setDeletionIds: Dispatch<SetStateAction<number[]>>;
+  onDeleteTodos: (ids: number[]) => void;
+};
+
+export const Footer: FC<Props> = ({
+  completedTodoIds,
+  uncompletedTodosAmount,
+  filterOption,
+  setFilterOption,
+  onDeleteTodos,
+}) => {
+  return (
+    <footer className="todoapp__footer" data-cy="Footer">
+      <span className="todo-count" data-cy="TodosCounter">
+        {uncompletedTodosAmount} items left
+      </span>
+
+      <nav className="filter" data-cy="Filter">
+        {Object.values(Filter).map(filter => {
+          return (
+            <a
+              href={filter === 'All' ? '#/' : `#/${filter.toLowerCase()}`}
+              className={cn('filter__link', {
+                selected: filter === filterOption,
+              })}
+              data-cy={`FilterLink${filter}`}
+              key={filter}
+              onClick={() => setFilterOption(filter)}
+            >
+              {filter}
+            </a>
+          );
+        })}
+      </nav>
+
+      <button
+        type="button"
+        className="todoapp__clear-completed"
+        data-cy="ClearCompletedButton"
+        onClick={() => onDeleteTodos(completedTodoIds)}
+        disabled={!completedTodoIds.length}
+      >
+        Clear completed
+      </button>
+    </footer>
+  );
+};
diff --git a/src/components/Footer/index.ts b/src/components/Footer/index.ts
new file mode 100644
index 000000000..ddcc5a9cd
--- /dev/null
+++ b/src/components/Footer/index.ts
@@ -0,0 +1 @@
+export * from './Footer';
diff --git a/src/components/Header/Header.tsx b/src/components/Header/Header.tsx
new file mode 100644
index 000000000..46e833ba5
--- /dev/null
+++ b/src/components/Header/Header.tsx
@@ -0,0 +1,96 @@
+import {
+  FC,
+  Dispatch,
+  SetStateAction,
+  useRef,
+  useEffect,
+  useState,
+} from 'react';
+import cn from 'classnames';
+import { InputForm } from '../InputForm';
+import { Todo } from '../../types/Todo';
+import { Errors } from '../../types/Errors';
+import { handleError } from '../../utils/handleError';
+import { postTodo, USER_ID } from '../../api/todos';
+
+type Props = {
+  todos: Todo[];
+  tempTodo: Todo | null;
+  uncompletedTodosAmount: number;
+  setTempTodo: Dispatch<SetStateAction<Todo | null>>;
+  setError: Dispatch<SetStateAction<Errors>>;
+  setTodos: Dispatch<SetStateAction<Todo[]>>;
+  onToggleCompletedAll: () => void;
+};
+
+export const Header: FC<Props> = ({
+  todos,
+  tempTodo,
+  uncompletedTodosAmount,
+  setTempTodo,
+  setError,
+  setTodos,
+  onToggleCompletedAll,
+}) => {
+  const [inputValue, setInputValue] = useState('');
+  const inputRef = useRef<HTMLInputElement | null>(null);
+
+  const handleSubmit = (event: React.FormEvent<HTMLFormElement>) => {
+    event.preventDefault();
+
+    const trimmedInputValues = inputValue.trim();
+
+    if (!trimmedInputValues) {
+      handleError(setError, Errors.EmptyTitle);
+
+      return;
+    }
+
+    const temporaryTodo: Todo = {
+      id: 0,
+      userId: USER_ID,
+      title: trimmedInputValues,
+      completed: false,
+    };
+
+    setTempTodo(temporaryTodo);
+
+    postTodo(temporaryTodo)
+      .then(res => {
+        setTodos(current => [...current, res]);
+        setInputValue('');
+        setTempTodo(null);
+      })
+      .catch(() => {
+        setTempTodo(null);
+        handleError(setError, Errors.AddTodo);
+      });
+  };
+
+  useEffect(() => {
+    inputRef.current?.focus();
+  }, [todos, tempTodo]);
+
+  return (
+    <header className="todoapp__header">
+      {!!todos.length && (
+        <button
+          type="button"
+          className={cn('todoapp__toggle-all', {
+            active: uncompletedTodosAmount === 0,
+          })}
+          data-cy="ToggleAllButton"
+          onClick={onToggleCompletedAll}
+        />
+      )}
+
+      <InputForm
+        handleSubmit={handleSubmit}
+        inputRef={inputRef}
+        tempTodo={tempTodo}
+        inputValue={inputValue}
+        setInputValue={setInputValue}
+      />
+    </header>
+  );
+};
diff --git a/src/components/Header/index.ts b/src/components/Header/index.ts
new file mode 100644
index 000000000..266dec8a1
--- /dev/null
+++ b/src/components/Header/index.ts
@@ -0,0 +1 @@
+export * from './Header';
diff --git a/src/components/InputForm/InputForm.tsx b/src/components/InputForm/InputForm.tsx
new file mode 100644
index 000000000..5f0810191
--- /dev/null
+++ b/src/components/InputForm/InputForm.tsx
@@ -0,0 +1,39 @@
+import {
+  Dispatch,
+  FC,
+  FormEventHandler,
+  MutableRefObject,
+  SetStateAction,
+} from 'react';
+import { Todo } from '../../types/Todo';
+
+type Props = {
+  handleSubmit: FormEventHandler<HTMLFormElement>;
+  inputRef: MutableRefObject<HTMLInputElement | null>;
+  tempTodo: Todo | null;
+  inputValue: string;
+  setInputValue: Dispatch<SetStateAction<string>>;
+};
+
+export const InputForm: FC<Props> = ({
+  handleSubmit,
+  inputRef,
+  tempTodo,
+  inputValue,
+  setInputValue,
+}) => {
+  return (
+    <form onSubmit={handleSubmit}>
+      <input
+        ref={inputRef}
+        data-cy="NewTodoField"
+        type="text"
+        className="todoapp__new-todo"
+        placeholder="What needs to be done?"
+        disabled={!!tempTodo}
+        value={inputValue}
+        onChange={event => setInputValue(event.target.value)}
+      />
+    </form>
+  );
+};
diff --git a/src/components/InputForm/index.ts b/src/components/InputForm/index.ts
new file mode 100644
index 000000000..139aee432
--- /dev/null
+++ b/src/components/InputForm/index.ts
@@ -0,0 +1 @@
+export * from './InputForm';
diff --git a/src/components/TodoBody/TodoBody.tsx b/src/components/TodoBody/TodoBody.tsx
new file mode 100644
index 000000000..f8dc4da01
--- /dev/null
+++ b/src/components/TodoBody/TodoBody.tsx
@@ -0,0 +1,135 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
+/* eslint-disable jsx-a11y/label-has-associated-control */
+import { FC, useEffect, useState, useRef } from 'react';
+import { Todo } from '../../types/Todo';
+import cn from 'classnames';
+import { Errors } from '../../types/Errors';
+
+type Props = {
+  todo: Todo;
+  deletionIds?: number[];
+  pendingTodos?: Todo[];
+  errorMessage: Errors;
+  onTodosChange?: any;
+  onDeleteTodos?: (ids: number[]) => void;
+};
+
+export const TodoBody: FC<Props> = ({
+  todo,
+  deletionIds,
+  pendingTodos,
+  errorMessage,
+  onTodosChange = () => {},
+  onDeleteTodos = () => {},
+}) => {
+  const [isEditing, setIsEditing] = useState(false);
+  const [newTitle, setNewTitle] = useState(todo.title);
+
+  const handleUpdateTodoTitle = (event: React.FormEvent<HTMLFormElement>) => {
+    event.preventDefault();
+
+    if (newTitle === todo.title) {
+      setIsEditing(false);
+
+      return;
+    } else if (!newTitle) {
+      onDeleteTodos([todo.id]);
+
+      return;
+    }
+
+    const updatedTodo = {
+      ...todo,
+      title: newTitle.trim(),
+    };
+
+    onTodosChange([updatedTodo]).then(() => setIsEditing(false));
+  };
+
+  const handleEscapeButton = (key: string) => {
+    if (key === 'Escape') {
+      setNewTitle(todo.title);
+      setIsEditing(false);
+    }
+
+    return;
+  };
+
+  const handleTodoStatus = () => {
+    const updatedTodo = {
+      ...todo,
+      completed: !todo.completed,
+    };
+
+    onTodosChange([updatedTodo]);
+  };
+
+  const isActive =
+    !todo.id ||
+    deletionIds?.includes(todo.id) ||
+    pendingTodos?.some(current => current.id === todo.id);
+
+  const inputRef = useRef<HTMLInputElement>(null);
+
+  useEffect(() => {
+    inputRef.current?.focus();
+  }, [isEditing, errorMessage]);
+
+  return (
+    <div
+      key={todo.id}
+      data-cy="Todo"
+      className={cn('todo', { completed: todo.completed })}
+      onDoubleClick={() => setIsEditing(true)}
+    >
+      <label className="todo__status-label">
+        <input
+          data-cy="TodoStatus"
+          type="checkbox"
+          className="todo__status"
+          checked={todo.completed}
+          onChange={handleTodoStatus}
+        />
+      </label>
+
+      {isEditing ? (
+        <form onSubmit={handleUpdateTodoTitle} onBlur={handleUpdateTodoTitle}>
+          <input
+            data-cy="TodoTitleField"
+            ref={inputRef}
+            type="text"
+            className="todo__title-field"
+            placeholder="Empty todo will be deleted"
+            value={newTitle}
+            onChange={event => setNewTitle(event.currentTarget.value)}
+            onKeyUp={event => handleEscapeButton(event.key)}
+          />
+        </form>
+      ) : (
+        <>
+          <span data-cy="TodoTitle" className="todo__title">
+            {todo.title}
+          </span>
+
+          <button
+            type="button"
+            className="todo__remove"
+            data-cy="TodoDelete"
+            onClick={() => onDeleteTodos([todo.id])}
+          >
+            ×
+          </button>
+        </>
+      )}
+      <div
+        data-cy="TodoLoader"
+        className={cn('modal overlay', {
+          'is-active': isActive,
+        })}
+      >
+        <div className="modal-background has-background-white-ter" />
+        <div className="loader" />
+      </div>
+    </div>
+  );
+};
diff --git a/src/components/TodoBody/index.ts b/src/components/TodoBody/index.ts
new file mode 100644
index 000000000..57926cb9c
--- /dev/null
+++ b/src/components/TodoBody/index.ts
@@ -0,0 +1 @@
+export * from './TodoBody';
diff --git a/src/components/TodoList/TodoList.tsx b/src/components/TodoList/TodoList.tsx
new file mode 100644
index 000000000..140e449bf
--- /dev/null
+++ b/src/components/TodoList/TodoList.tsx
@@ -0,0 +1,41 @@
+import { FC } from 'react';
+import { Todo } from '../../types/Todo';
+import { TodoBody } from '../TodoBody';
+import { Errors } from '../../types/Errors';
+
+type Props = {
+  todos: Todo[];
+  tempTodo: Todo | null;
+  deletionIds: number[];
+  pendingTodos: Todo[] | undefined;
+  errorMessage: Errors;
+  onTodosChange: (newTodos: Todo[]) => void;
+  onDeleteTodos: (ids: number[]) => void;
+};
+
+export const TodoList: FC<Props> = ({
+  todos,
+  tempTodo,
+  deletionIds,
+  pendingTodos,
+  errorMessage,
+  onTodosChange,
+  onDeleteTodos,
+}) => {
+  return (
+    <section className="todoapp__main" data-cy="TodoList">
+      {todos.map(todo => (
+        <TodoBody
+          key={todo.id}
+          todo={todo}
+          deletionIds={deletionIds}
+          pendingTodos={pendingTodos}
+          errorMessage={errorMessage}
+          onTodosChange={onTodosChange}
+          onDeleteTodos={onDeleteTodos}
+        />
+      ))}
+      {tempTodo && <TodoBody todo={tempTodo} errorMessage={errorMessage} />}
+    </section>
+  );
+};
diff --git a/src/components/TodoList/index.ts b/src/components/TodoList/index.ts
new file mode 100644
index 000000000..f239f4345
--- /dev/null
+++ b/src/components/TodoList/index.ts
@@ -0,0 +1 @@
+export * from './TodoList';
diff --git a/src/types/Errors.ts b/src/types/Errors.ts
new file mode 100644
index 000000000..358b045c8
--- /dev/null
+++ b/src/types/Errors.ts
@@ -0,0 +1,8 @@
+export enum Errors {
+  Default = '',
+  LoadingTodos = 'Unable to load todos',
+  EmptyTitle = 'Title should not be empty',
+  AddTodo = 'Unable to add a todo',
+  DeleteTodo = 'Unable to delete a todo',
+  UpdateTodo = 'Unable to update a todo',
+}
diff --git a/src/types/Filter.ts b/src/types/Filter.ts
new file mode 100644
index 000000000..66887875b
--- /dev/null
+++ b/src/types/Filter.ts
@@ -0,0 +1,5 @@
+export enum Filter {
+  All = 'All',
+  Active = 'Active',
+  Completed = 'Completed',
+}
diff --git a/src/types/Todo.ts b/src/types/Todo.ts
new file mode 100644
index 000000000..3f52a5fdd
--- /dev/null
+++ b/src/types/Todo.ts
@@ -0,0 +1,6 @@
+export interface Todo {
+  id: number;
+  userId: number;
+  title: string;
+  completed: boolean;
+}
diff --git a/src/utils/fetchClient.ts b/src/utils/fetchClient.ts
new file mode 100644
index 000000000..33e705a0c
--- /dev/null
+++ b/src/utils/fetchClient.ts
@@ -0,0 +1,42 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
+const BASE_URL = 'https://mate.academy/students-api/';
+
+function wait(delay: number) {
+  return new Promise(resolve => {
+    setTimeout(resolve, delay);
+  });
+}
+
+type RequestMethod = 'GET' | 'POST' | 'PATCH' | 'DELETE';
+
+function request<T>(
+  url: string,
+  method: RequestMethod = 'GET',
+  data: any = null,
+): Promise<T> {
+  const options: RequestInit = { method };
+
+  if (data) {
+    options.body = JSON.stringify(data);
+    options.headers = {
+      'Content-Type': 'application/json; charset=UTF-8',
+    };
+  }
+
+  return wait(100)
+    .then(() => fetch(BASE_URL + url, options))
+    .then(response => {
+      if (!response.ok) {
+        throw new Error();
+      }
+
+      return response.json();
+    });
+}
+
+export const client = {
+  get: <T>(url: string) => request<T>(url),
+  post: <T>(url: string, data: any) => request<T>(url, 'POST', data),
+  patch: <T>(url: string, data: any) => request<T>(url, 'PATCH', data),
+  delete: (url: string) => request(url, 'DELETE'),
+};
diff --git a/src/utils/getFilteredTodos.ts b/src/utils/getFilteredTodos.ts
new file mode 100644
index 000000000..804447f33
--- /dev/null
+++ b/src/utils/getFilteredTodos.ts
@@ -0,0 +1,15 @@
+import { Filter } from '../types/Filter';
+import { Todo } from '../types/Todo';
+
+export const getFilteredTodos = (todos: Todo[], filter: Filter): Todo[] => {
+  return todos.filter(todo => {
+    switch (filter) {
+      case Filter.Completed:
+        return todo.completed;
+      case Filter.Active:
+        return !todo.completed;
+      default:
+        return true;
+    }
+  });
+};
diff --git a/src/utils/handleError.tsx b/src/utils/handleError.tsx
new file mode 100644
index 000000000..275a915d9
--- /dev/null
+++ b/src/utils/handleError.tsx
@@ -0,0 +1,12 @@
+import { Errors } from '../types/Errors';
+import { Dispatch, SetStateAction } from 'react';
+
+export const handleError = (
+  setError: Dispatch<SetStateAction<Errors>>,
+  error: Errors,
+) => {
+  setError(error);
+  setTimeout(() => {
+    setError(Errors.Default);
+  }, 3000);
+};