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Introduction to Redux

Rules for Reducers

There are certain rules while using Redux Reducers which we need to follow to avoid certain bugs or surprises.

  • Reducers should use only the state and action arguments to calculate the new state. They shouldn't access any external values;
  • Reducers must not perform asynchronous logic or side effects such as making API calls or running timers etc.;
  • The state should not be directly modified inside the reducer functions, instead, the reducer function should return a duplicate state object with updated values. This rule only applies when creating reducers manually. If we use createSlice to create a slice, we can modify the state directly.

It is important to note that in the case of createSlice reducers, we directly modify the state object, however, in the backend, Redux creates a new duplicate object and assigns it the new changes, so the rule is being followed, but in the backend.

In which case can we directly modify the state?

Select the correct answer

Everything was clear?

Section 3. Chapter 10
course content

Course Content

Introduction to Redux

Introduction to Redux

1. Getting Started

What is Redux?Why Redux? When to use Redux?Setting up a React-Redux Application

2. Fundamental Concepts

Redux ActionsRedux ReducersRedux StoreStore Dispatch MethodSelectorsRedux Data Flow

3. Redux in Practice

Redux Application Structure Modifying the Template for UseCreating the Redux StoreRedux SliceCreating a SliceUnderstanding SliceUsing Selectors to access StateModifying State by Dispatching ActionsThunk FunctionsRules for ReducersUnderstanding the Counter Application

4. Creating a React-Redux Application

The ApplicationSetting Up the ApplicationCreating the UI SkeletonCreating the Profile SliceCreating the Posts SliceCompleting the Posts featureDisplaying Number of Posts and UsersAdding CSS Styling

Rules for Reducers

There are certain rules while using Redux Reducers which we need to follow to avoid certain bugs or surprises.

  • Reducers should use only the state and action arguments to calculate the new state. They shouldn't access any external values;
  • Reducers must not perform asynchronous logic or side effects such as making API calls or running timers etc.;
  • The state should not be directly modified inside the reducer functions, instead, the reducer function should return a duplicate state object with updated values. This rule only applies when creating reducers manually. If we use createSlice to create a slice, we can modify the state directly.

It is important to note that in the case of createSlice reducers, we directly modify the state object, however, in the backend, Redux creates a new duplicate object and assigns it the new changes, so the rule is being followed, but in the backend.

In which case can we directly modify the state?

Select the correct answer

Everything was clear?

Section 3. Chapter 10
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