First will add TodoListAppContainer.js file.
App.js file accordingly.
TodoAppContainer.js file, will add constants for api url and headers for api endpoint.
componentDidMount lifecycle method, will do data fetching action. For data fetching, will use window.fetch function, which is easier and handle responses than using XMLHttpRequest. However, most of the browsers are not support this feature. Therefore will use whatwg-fetch node package. Install whatwg-fetch package and change TodoAppContainer.js file accordingly.
itemId and itemIndex values accordingly from TodoList.js file.