Why Redux is used?

Redux is a Predictable State Container for JS Apps. It is predictable, centralized, debuggable and flexible. It is useful for predictable all states. Redux provides a centralized store. It's amazing feature is time travelling debugging. You can literally go to the previous state and show your UI.

• Store contains the state because we can’t change state directly.
• State define UI. We bind our UI with state.
• We create each actions for each component. [accordingly to each state ]
• Reducer is pure javascript function. Each reducer manages independent state in complete store. All reducer functions are called when action is dispatched. Reducer update the state.
• Redux store change the UI.

Actions

• Action is package of information which is passed the store. It is used for current state in application.They are plain JS objects. Payload is the information or data for action.
• Action - dispatch – store
• Action creators for each different action.

Reducers

• Reducer is pure javascript function. It only depend on it argument.
• They are called automatically when an action is dispatched.
• They are responsible for a particular state in store
• Reducers return the new form of state.
• They should split into multiple small reducers to manage a small set of data in store.
• They should not change the state, it should return the new form of state.