Architechture

This app is built base on Redux architechture with three principles:

Single source of truth: The state of your whole application is stored in an object tree within a single store.
State is read-only: The only way to change the state is to emit an action, an object describing what happened.
Changes are made with pure functions: To specify how the state tree is transformed by actions, you write pure reducers.

Some important classes

Action: An object describing what happened in the app. Actions contain some minimal data to indentify a modify the state. An action will be emmited by UI components or other part of the app. Some subclasses are:
- AddAction: Add new task action.
- DeleteAndToggleAction: Delete or toggle state task action.
State: An object storing all the app state include some data, UI state. In this app, the state object contains a list of tasks.
Reducer: Take the previous state and an action, then change the state according to the specific action and return the next application state.
Store:
- Hold the application state and allow access to state via getState().
- A reducer to reduce the next app state. The store object allows emit an action to update the app state via dispatch(action).
- List of change listener. It will be call any time an action dispatched. The store object also allows unregister the listener from list of change listener.