We’ll talk about the other Redux-related packages as we go through the rest of the tutorial. Redux helps you manage “global” state – state that is needed across many parts of your application. The new version of Context API is a dependency injection mechanism that allows passing data through the component tree without having to pass props down manually at every level. The most prominent benefit is improved state management for your application. We can listen for the click event and dispatch a new action to the Redux store, which contains the reducer. Note that the state parameter is a default parameter which accepts an initial state.
Different patterns and architectures don’t have pros and cons in isolation, they only have pros-and-cons in comparison to some other architecture or pattern. So far you’ve only written about Redux – you need to compare it to something first. Some of that complexity is obvious while many other unobvious gotchas are hidden and waiting for you to trip on it. Even then it is worth checking out alternatives such as MobX or react-sweet-state.
Understanding Redux: A tutorial with examples
Functional programming involves writing simpler, smaller and isolated functions. By following this pattern, code maintenance, testing and debugging what is redux is made easier. Since the functions are small and isolated, that makes them reusable thus they can be copied and pasted anywhere they are needed.
Similarly, removing an item from the cart should decrease the number of items in the cart internally. It should remove the item from the cart object and also display the updated total number of items in the cart in the UI. An e-commerce website will have several components like the cart component, user profile component, previously viewed section component, and so on. Well, an application has its state, which can be a combination of the states of its internal components. The good news is that this means Redux can be used in many different ways.
When not to choose Redux?
If you feel middleware is required, you will appreciate its capacity to enable great work with the best abstraction. The reducer in Redux is a normal, pure function that takes care of the various possible values of state using the switch case syntax. But that means several things need to be taken care of — most importantly, keeping the state immutable. 💡 A pure function is a function that will always return the same value if given the same parameters, i.e., the function depends on only the parameters and no external data.
Accusations of needing boilerplate code is not a criticism of Redux I’m familiar with. On the contrary, Redux actually reduces boilerplate compared to the older Flux pattern. I have made views for some complex use-cases using react-redux. I think it is also meaningless that there is a performance down due to hundreds of KB of Redux packages.
Debugging is easy in Redux
React advises that if you must do this, you can build your global event system following Flux’s pattern — and that’s where Redux comes in. Action objects always have a type field, which is a string you provide that
acts as a unique name for the action. The type should be a readable name so that
anyone who looks at this code understands what it means. In this case, we use the
word ‘counter’ as the first half of our action type, and the second half is a
description of “what happened”. In this case, our ‘counter’ was ‘incremented’, so
we write the action type as ‘counter/incremented’.
This is to handle the scenario when the reducer is called for the first time when the state value is undefined. For example, there can be a reducer handling the state of the cart in a shopping application, then there can be a reducer handling the user details part of the application, and so on. And firing the action of adding one item to the cart again will increase the number of items in the cart to 2. “Actions can be recorded and replayed later, so this makes state management predictable. With the same actions in the same order, you’re going to end up in the same state.”
Understanding React Redux
Without Redux, you would need some other event system or have to instantiate the snackbar component every time it gets used. In other words, the Redux pattern provides state management for JavaScript apps. You can use the Redux library with any frontend framework, such as React, Angular, or even Vue. In the end, you can implement the Redux pattern in any vanilla JS application. This means that your own component will need to re-render less often, because most of the time those specific pieces of data haven’t changed.
- I have made views for some complex use-cases using react-redux.
- There are three core components in Redux — actions, store, and reducers.
- Ideally, the data in a component should live in just one component, so sharing data among sibling components becomes difficult.
- Therefore, make sure to check if you need Redux before introducing its complexity.
Instead of directly exploring examples, let’s learn more about the problem Redux solves. While Redux can be used with any UI layer, it was originally designed and intended for use with React. There are UI binding layers for many other frameworks, but React Redux is maintained directly by the Redux team. To understand why you should use React Redux, it may help to understand what a “UI binding library” does.
An introduction to Redux
However, situations occur where we have to share a state with a child component or a child component wants to modify the parent component’s state. As mentioned in the introduction, Redux is a pattern that facilitates state management. It allows you to maintain a predictable state container for your JavaScript apps. This is important for consumer-facing applications where the interface changes based on user input.
So, the reducers make a copy of the entire current state first, make the necessary changes, and then return a fresh new instance of the state – with all the necessary changes/ updates. In the following section, we will dive deep into the core concepts of Redux – the store, actions and reducers. Whenever a user adds an item to the cart, the application has to internally handle that action by adding that item to the cart object. It has to maintain its state internally and also show the user the total number of items in the cart in the UI. We’ll take the cart component which displays the number of items in a user’s cart.
Redux Application Data Flow
Redux is a pattern and library for managing and updating application state, using events called “actions”. It serves as a centralized store for state that needs to be used across your entire application, with rules ensuring that the state can only be updated in a predictable fashion. This tutorial will introduce you to the core concepts, principles, and patterns for using Redux. By the time you finish, you should understand the different pieces that make up a Redux app, how data flows when using Redux, and our standard recommended patterns for building Redux apps. Therefore, make sure to check if you need Redux before introducing its complexity.
