Readings: Redux - Additional Topics
Review, Research, and Discussion
- What’s the best practice for “pre-loading” data into the store (on application start) in a Redux application?
- The most ‘redux-like’ way of handling the pre-loading of data would be to fire off the asynchronous action in the lifecycle method (probably componentWillMount ) of a Higher Order Component that wraps your app.
- When using a thunk/async action that dispatches the actual action, which do you export from your reducer?
- A first approach is based on the Thunk middleware. The role of this middleware is very simple: verify if an action is a function and in which case execute it. This simple behaviour allows us to create actions no longer as simple objects, but as functions, which therefore have business logic.
- So, in order to solve our problem with asynchronous tasks, we can define an action as a function that starts an asynchronous task and delegates its execution to the thunk middleware. Unlike the reducer, middleware is not required to be a pure function, so the thunk middleware can perform functions that trigger side effects without any problem.
Vocabulary
- middleware
- Middleware is software that lies between an operating system and the applications running on it. Essentially functioning as hidden translation layer, middleware enables communication and data management for distributed applications.
- Thunk
- Thunk is a programming concept where a function is used to delay the evaluation/calculation of an operation.
- Redux Thunk is a middleware that lets you call action creators that return a function instead of an action object. That function receives the store’s dispatch method, which is then used to dispatch regular synchronous actions inside the function’s body once the asynchronous operations have been
Preparation
- Redux Toolkit
- The Redux Toolkit package is intended to be the standard way to write Redux logic. It was originally created to help address three common concerns about Redux:
- “Configuring a Redux store is too complicated”
- “I have to add a lot of packages to get Redux to do anything useful”
- “Redux requires too much boilerplate code”
- We can’t solve every use case, but in the spirit of create-react-app and apollo-boost, we can try to provide some tools that abstract over the setup process and handle the most common use cases, as well as include some useful utilities that will let the user simplify their application code.
- Redux Toolkit also includes a powerful data fetching and caching capability that we’ve dubbed “RTK Query”. It’s included in the package as a separate set of entry points. It’s optional, but can eliminate the need to hand-write data fetching logic yourself.
- These tools should be beneficial to all Redux users. Whether you’re a brand new Redux user setting up your first project, or an experienced user who wants to simplify an existing application, Redux Toolkit can help you make your Redux code better.
- The Redux Toolkit package is intended to be the standard way to write Redux logic. It was originally created to help address three common concerns about Redux:
- Redux Toolkit includes these APIs:
- configureStore(): wraps createStore to provide simplified configuration options and good defaults. It can automatically combine your slice reducers, adds whatever Redux middleware you supply, includes redux-thunk by default, and enables use of the Redux DevTools Extension.
- createReducer(): that lets you supply a lookup table of action types to case reducer functions, rather than writing switch statements. In addition, it automatically uses the immer library to let you write simpler immutable updates with normal mutative code, like state.todos[3].completed = true.
- createAction(): generates an action creator function for the given action type string. The function itself has toString() defined, so that it can be used in place of the type constant.
- createSlice(): accepts an object of reducer functions, a slice name, and an initial state value, and automatically generates a slice reducer with corresponding action creators and action types.
- createAsyncThunk: accepts an action type string and a function that returns a promise, and generates a thunk that dispatches pending/fulfilled/rejected action types based on that promise
- createEntityAdapter: generates a set of reusable reducers and selectors to manage normalized data in the store
- The createSelector utility from the Reselect library, re-exported for ease of use.
- Alternative State Managers
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| Read | Title | ToGo |
|---|---|---|
| Read: 01 | Pre-Work - Code 401: Advanced Javascript Development |  |
| Read: 02 | Readings: Express | |
| Read: 03 | Readings: Express REST API | |
| Read: 04 | Readings: Data Modeling | |
| Read: 06 | Readings: Authentication | |
| Read: 07 | Reading: Bearer Authorization | |
| Read: 08 | Reading: Access Control (ACL) | |
| Read: 09 | Reading: OAuth 2 | |
| Read: 11 | Readings: Event Driven Applications | |
| Read: 12 | Readings: Socket.io | |
| Read: 13 | Readings: Message Queues | |
| Read: 14 | Readings: Event Driven Architecture | |
| Read: 16 | Readings: AWS: Cloud Servers | |
| Read: 17 | Readings: AWS: S3 and Lambda | |
| Read: 18 | Readings: AWS: API, Dynamo and Lambda | |
| Read: 18 | Readings: AWS: Events | |
| Read: 26 | Reading: Component Based UI | |
| Read: 27 | Reading: Props and State | |
| Read: 28 | Readings: Component Composition | |
| Read: 29 | Readings: Routing | |
| Read: 31 | Reading: Hooks API | |
| Read: 32 | Reading: Custom Hooks | |
| Read: 33 | Reading: Context API | |
| Read: 34 | Reading: <Login /> and <Auth /> |
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| Read: 36 | Reading: Application State with Redux | |
| Read: 37 | Readings: Redux - Combined Reducers | |
| Read: 38 | Readings: Redux - Asynchronous Actions | |
| Read: 39 | Readings: Redux - Additional Topics | |