Redux - ryantc94/Knights-of-Arthur GitHub Wiki

Core Concepts

https://developer.apple.com/library/content/documentation/General/Conceptual/DevPedia-CocoaCore/ModelObject.html

• Actions are objects that describe changes to state
• Reducers are functions that take state and actions and return next state, with one main reducer that returns entire new state

Three Principles

• Store contains all state
• State is read-only and can only be changed by dispatching action
• Reducers have to be pure functions

Actions

Actions: data payloads that send information from application to the store, and are the only information stores can receive.

• store.dispatch(), dispatches an action to update the store
• Actions are plain javaScript objects, and they must have a property 'type'

{
  //'type' is required
  type: 'example_action',
  text: 'This action is an example'
}

Action Creators

• Action Creators are functions that create actions.

function actionCreator(text) {
  return {
    type: 'example_action',
    text
}

• Action creator dispatch (why cant dispatch be in the action creator and has to be given to dispatch)???

Reducers

Designing State Shape

https://github.com/paularmstrong/normalizr

Handling Actions

Reducers: specifies how the state changes in response to dispatched action.

• Reducers are called reducers because they are the type of function you would pass to Array.prototype.reducer
• Reducers must remain pure: never mutate args, never perform side affects like API calls/routing, never call non-pure functions
• Redux will call reducer with an undefined state for the first time, so the reducer should catch this
• Reducers must assign the state change to a new object or return the original state, it must not mutate the passed in state object

Store

Data Flow

Redux + React

https://github.com/reactjs/react-redux

Async Actions