==

!==

Why?

Redux complies with Flux definition

 (state, action) => state

....

but Redux doesn't have dispatcher contept and store data is immutable

What's redux?

Single source of truth

{
    "user": {
        "name": "",
        "id": "",
        "email: ""
        },
    "checkout": {
        "items": [{..}],
        "total": 1000,
        "shipping": {...}
    },
    "offerItems": [{...}],
    ...
}

The state of your whole application is stored in an object tree within a single store.

State is read-only

App state is immutable and can only be change with an action call.

const fetchUsers = {
    type: 'FETCHING_USERS'
}

const usersFetch = {
    type: 'USERS_FETCHED',
    payload: [{...}]
}

const fetchingUsersFailed = {
    type: 'FETCHING_USERS_FAILED'
}

Actions are executed one by one in strict order so it's easy to debug, control and maintain state

Changes are made with pure functions

function counter(state = 0, action) {  
    switch (action.type) {
        case 'INCREMENT':
            return ++state;
        case 'DECREMENT':
            return --state;
    }
    return state;
}

Executing reducer functions with state and dispatched action is only way to modify store.

Redux flow

Actions

• are payloads of data to modify app state

Simple as that.

Reducers

• are pure functions -> no side effects
• describe based on action how the state changes
• can be splited by functionality and then combine together

Store

Brings together actions and reducers

• dispatch actions store.dispatch(action)
• holds application state
• allow access to state via store.getState()