This is called props drilling and this is avoided by using a global store which is accessible to whole app. Any "state management" is done by you and your own code, typically via useState/useReducer. If you want a proper introduction to this subject, you can join the waitlist for Context in React allows you to pass data to any component without “prop drilling”. Redux on the other hand needs to install separately. We're going to build the same project with React context. I.e. Sure, it's possible to write code that way, but at that point you're just reinventing React-Redux, poorly. Combine all reducer, though we have only one reducer, but we are following a convention to adapt more reducers later. Data fetching libraries like React Query, SWR, Apollo, and Urql all provide abstractions that simplify common patterns for working with cached server state (and the upcoming "RTK Query" library will do the same for Redux Toolkit). React-Redux provides a connect function for you to read values from the Redux store. The RTK is the polish that helped me convince the rest of the teams to buy into the refactor. React uses provider pattern in Context API to share data across the tree descendant nodes. React Context vs Redux Store. What's the exact difference between props and state?. Notice that it does not say anything about "managing" values - it only refers to "passing" and "sharing" values. Using React Context in an app requires a few steps: Whenever the parent component re-renders and passes in a new reference to the context provider as the value, any component that reads from that context will be forced to re-render. React's Context API has become the state management tool of choice for many, oftentimes replacing Redux altogether. Reduce React State with Hooks and Context. I guess Context is more like hidden props than abstracted state. Not to mention how much easier it is to process data. No. As we established earlier, Context does not "store" anything itself. locale preference, UI theme) that are required by many components within an application. Because of this, React-Redux can also be used to avoid prop-drilling, specifically because React-Redux uses Context internally. Follow. share data that can be considered “global” for a tree of React components So, when most people refer to "Redux", they actually mean "using a Redux store and the React-Redux library together". We focus on the advantages and disadvantages of React Context and Redux to recap and clarify what is a best tool for react app. This is a post in the Blogged Answers series. The whole state of your app is stored in an object tree inside a single store. Making context more like Redux. Any time you have some value that you want to make accessible to a portion of your React component tree, without passing that value down as props through each level of components. Since many components relied on shouldComponentUpdate for performance optimizations, that made legacy context useless for passing down plain data. Ever since we started using React to rebuild our UI at uberVU (now Hootsuite) the #1 developer question has probably been:. In this code snippet, you created a React Context then you wrapped MyApp Component into the context Provider and finally, you have bound MyComponent with the context using static contextType = StoreContext. Yes, Context + useReducer does look an awful lot like Redux + React-Redux. One problem with the "Context vs Redux" discussions is that people often actually mean "I'm using useReducer to manage my state, and Context to pass down that value". The only overlap between them, really, is "can be used to avoid prop-drilling". There's many nuances to this discussion. In this article, we share a short overview of state management, context API, and Flux architecture. You put something in the top end of the pipe using the , and that one thing (whatever it is) goes down through the pipe until it pops out the other end where another component asks for it with useContext(MyProvider). So, in order to actually know when to use them, we need to first clearly define what they do and what problems they solve. The actual "state management" is happening with the useState/useReducer hook. Wow, we are almost done. I realize that this post won't stop the seemingly never-ending debate over "Context vs Redux?!?!?!?!?". You need to determine which of these tools best matches the set of problems that you're trying to solve! This is actually an example of using Context for dependency injection, as mentioned above. On the other hand for complex or high-frequency update Redux should be used, React Context won’t be a good solution. In /redux/reducers/ create a reducer for adding user data. React context, on the other hand, works on the state principle which is already a part of React, we only need to understand the additions to the API and how we can use the providers and consumers. I used it in my apps, quickly forgot about Redux, and never looked back. Definitive answers and clarification on the purpose and use cases for Context and Redux . By the way, this post is the follow-up of my previous one 7 steps to understand React Redux. However, this pattern comes handy when you are designing a complex app since it solves multiple problems. Also, it is possible to update the context data from any subscribed component. In my opinion, a react developer can get familiarized with the concept in a short while To do this, we wrap our app with the API provided by React-Redux. However, it's critical to note that React-Redux only passes down the Redux store instance via context, not the current state value!. in another way, React Context API is a State management tool in the functional components. Denny Scott: Redux vs Context vs State - an in-depth look at state management in React, Maximilian Schwarzmüller: Redux vs React's Context API, Jakob Lind: When to use Redux, Context, and props, Blogged Answers: Why React Context is Not a "State Management" Tool (and Why It Doesn't Replace Redux), Presentations: Intro to React, Redux, and TypeScript (2020), Presentations: Podcast Appearances in 2020, Coding Career Advice: Searching and Evaluating Online Information Efficiently, How Web Apps Work: AJAX, APIs, and Data Transfer, Greatest Hits: The Most Popular and Most Useful Posts I've Written, Global React Meetup: The State of Redux 2020, The History and Implementation of React-Redux, Thoughts on React Hooks, Redux, and Separation of Concerns, React Boston 2019: Hooks HOCs, and Tradeoffs, You have larger amounts of application state that are needed in many places in the app, The app state is updated frequently over time, The logic to update that state may be complex, The app has a medium or large-sized codebase, and might be worked on by many people, You want to be able to understand when, why, and how the state in your application has updated, and visualize the changes to your state over time, You need more powerful capabilities for managing side effects, persistence, and data serialization, Then, in any component nested inside that provider, call, says that the purpose of Redux is to help you understand how state changes over time, Wanting to write your state management logic completely separate from the UI layer, Sharing state management logic between different UI layers (such as an application that is being migrated from AngularJS to React), Using the power of Redux middleware to add additional logic when actions are dispatched, Being able to persist portions of the Redux state, Enabling bug reports that can be replayed by developers, Faster debugging of logic and UI while in development, store an initial value by calling the hook, read the current value, also by calling the hook, Know that the value has been updated because the component re-rendered, Redux stores an initial value by calling the root reducer, lets you read the current value with, MobX stores an initial value by assigning field values in a store class, lets you read the current value by accessing the store's fields, updates values by assigning to those fields, and notifies that changes happened via, Passes down a single value, which could be anything (primitive, objects, classes, etc), Does show the current context value for both, Updates consuming components when the context value changes, but with no way to skip updates, Does not include any mechanism for side effects - it's purely for rendering components, Stores and manages a single value (which is typically an object), Works with any UI, including outside of React components, Can update the value via dispatching an action and running reducers, Has DevTools that show the history of all dispatched actions and state changes over time, Uses middleware to allow app code to trigger side effects, Allows components to subscribe to store updates, extract specific pieces of the store state, and only re-render when those values change, a way to pass down that value and read it in nested components, Passing down a value to nested components without prop-drilling, Moderately complex React component state management using a reducer function. Along with Reducer Hooks API, the React Context API provides all the ingredients necessary to replace Redux in many usages. Context provides a way to pass data through the component tree without having to pass props down manually at every level. Without React Context or Redux, we resort to a technique called “prop drilling” where we pass data down components even though some of those components don’t need that specific data. It’s a predictable state container for JavaScript apps. As someone that looked at Redux as a junior developer and instantly felt defeated, learning about context was a relief. They are different tools that do different things, and you use them for different purposes. Redux vs Context. To use these context data need to import useContext hook in the components. Jotai, Recoil, and Zustand offer lighter-weight state update approaches. Based on that, we can say that "state management" means having ways to: There's also typically a way to be notified when the current value has changed. It’s also good to use it in the same way as old context was used. The React Context API is React’s way of managing state in multiple components that are not directly connected. React’s provider pattern is a powerful concept. For the last few years, Redux has been THE state management solution for bigger React apps. When you have moderately complex React component state management needs within a specific section of your application. Redux, however, comes with its own complexities and challenges. It's also good to use it in the same way as old context was used. Finishing with the comment of Sebastian Markbåge (Facebook React Team), My personal summary is that new context is ready to be used for low frequency unlikely updates (like locale/theme). The actual Redux store is injected into the tree at runtime using the React-Redux component. To specify how the actions transform the state tree, you have to write pure reducers. This is only possible because React-Redux uses Context internally. Think of it this way. November 28, 2019. So, even though Context + useReducer sorta-resemble Redux + React-Redux at a quick glance... they are not fully equivalent and cannot truly replace Redux! The way components communicate and share state with each other, defines their success story. We specifically encourage putting "global state" in Redux and "local state" in React components, and carefully deciding whether each piece of state should live in Redux or component state. Given the prevalence of questions on this topic, I'm putting together this post as a definitive answer to those questions. The React Context API can replace the state management aspect of of Redux, because both of them have to do with managing complex, nested state without having to pass it down through the Component Tree as props. In this part, we’ll dive into how React Hooks can be used in conjunction with the Context API. React-Redux allows any React component in the application to talk to the Redux store. In React, data is often passed from a parent to its child component as a property. You already get basic knowledge of Redux and React Context. Add 3 files: actions.js, reducers.js, StoreContext.js. The connect function takes two arguments, both optional: So we are going to use connect in our App component. Moderately complex React component state management using a reducer function, Moderate to highly complex state management using reducer functions, Traceability for when, why, and how state changed over time, Sharing state management logic between different UI layers, All of the use cases for Redux, plus interacting with the Redux store in your React components, If the only thing you need to do is avoid prop-drilling, then use Context, If you've got some moderately complex React component state, or just really don't want to use an external library, go with Context +, If you want better traceability of the changes to your state over time, need to ensure that only specific components re-render when the state changes, need more powerful capabilities for managing side effects, or have other similar problems, use Redux + React-Redux. Imran Sayed. Context API is built-in with React 16.3.0 later versions. Context Vs Props in React. However, now that the temperature is coming from the parent as a prop, the TemperatureInput has no control over it.. React Context API Introduction. In React, this is usually solved by making a component “controlled”. Historically, Redux was originally created as an implementation of the "Flux Architecture", which was a pattern first suggested by Facebook in 2014, a year after React came out. Chris Achard: Can You Replace Redux with React Hooks? But communication among the components is an important part. One can declare state in top component and use it in child component with the help of React Context API. Let's recap the use cases for each of these: Again, these are different tools that solve different problems! Fantastic stuff in the toolkit. React Context for State Management React 16.3 added a new Context API – new in the sense that the old context API was a behind-the-scenes feature that most people either didn’t know about, or avoided using because the docs said to avoid using it. Let's review what capabilities Context and React+Redux actually have: So, clearly these are very different tools with different capabilities. Context has little to do with state management. So create a file UserContext.js in the root of /src folder. Redux helps you manage "global" state - state that is needed across many parts of your application. According to the docs, To create maintainable software by separating different parts of logic and state into dedicated components is a bit tricky. for static values and then propagate updates through subscriptions. Even when you are looking at the App Component and you know there is a problem in one of the properties of state, but you have to look at all the components which are Consuming it to figure out which one of them caused the problem. It’s far from being dead and yet, a strong enemy is arising: React’s Context API! Until the new context API was released, React made it difficult to use context with PureComponent or shouldComponentUpdate. Now the Context is ready to be used. It's also important to point out that these are not mutually exclusive options - you can use Redux, Context, and useReducer together at the same time! As I said above, my habit is to use a tool like Redux or Apollo for my data management, my React state handles local information, often UI state, and context handles static data, such as theming. Sadly, most of this "debate" stems from confusion over the purpose and use cases for these two tools. I hope to provide a simplified explanation and tutorial so that you can quickly add global state to any of your React apps. No. Architecturally, Redux emphasizes using functional programming principles to help you write as much of your code as possible as predictable "reducer" functions, and separating the idea of "what event happened" from the logic that determines "how the state updates when that event happens". There, I dive into what the Context API is all about and how it compares to Redux - the predominant global state management solution for React apps. It's not ready to be used as a replacement for all Flux-like state propagation. Context is how state (that exists somewhere already) is shared with other components. Many people chose Redux early on specifically to let them avoid prop-drilling, because React's legacy context was broken and React-Redux worked correctly. That thing processes a little over $1B/year. First, we need to make the store available to our app. So here are our components look like. React's useState and useReducer hooks are good example of state management. There are three principles of Redux: Single source of truth; State is read-only We know that our Redux-connected React components need to talk to a Redux store, but we don't know or care which Redux store that is when we define the component. Modern front-end frameworks like React, Vue, and Angular has changed the way our web looks like today. So, how do you decide whether to use Context, Context + useReducer, or Redux + React-Redux? Instead of explicitly putting a new value into a yourself, you can put that data into the Redux store and then access it anywhere. Pulling in the context state, making a changing and having it be persisted. So, let's talk about the Context + useReducer combination specifically. React Context does not meet those criteria. First of all, we will create a context for user data. Its really simple, right? The React Context API provides a way to pass data through the component tree without having to pass props down manually to every level. The parent component that renders a is responsible for deciding what value is passed into the context, and that value typically is based on React component state. You may not find this useful when you are using plain react. Notes on React Context API, how to create a Context, consume it, and pass values to a Context Provider. React Contex t Providers can work hand-in-hand with a Redux store for project setups that rely on both state management solutions. Inside this folder we will create below files. Conceptually, this is a form of "Dependency Injection". A solution to manage the global state of a React application using hooks and the Context API. This is known as the React Context API and it can be a bit tricky to learn. As I said earlier, it's critical to understand what problems a tool solves, and know what problems you have, in order to correctly choose the right tool to solve your problems. That's a common cause of the confusion I see, and it's really unfortunate because it helps perpetuate the idea that Context "manages state". We will use a simple example that will help us to understand the main concept of Context. Eric Elliott: Do React Hooks Replace Redux? We could divide that into categories like "server state", "communications state", and "location state" if we want to, but the key point is that there is data being stored, read, updated, and used. It's fairly easy to understand how they work—especially when seen in context—but it's also a bit difficult to grasp them conceptually. A developer walks us through the ways in which state is stored in component and context layers of a React.js application, and how to make this work in our code. Passing data to deeply nested child components can be cumbersome, especially when dealing with child components several levels down a component tree. In this quick 5-minute tutorial, you'll see an introduction to what Context is and how to use it! React Consumer example on CodeSandbox.. First, we create a new context, which we store in NumberContext.This is an object with 2 properties: Provider and Consumer.They’re a matched pair, and they’re born knowing how to communicate with each other (but not with other contexts). So we don’t need to install any extra packages for managing packages. For simple or low-frequency updates like theme settings, user authentication data, React Context is the perfect choice. For example if you want to store user data in your app then you manually need to pass it from parent to child and in case no of child tree is too much it become really difficult to handle because some time middle child don’t even use that data. Our official Redux Toolkit package eliminates those "boilerplate" concerns, and the React-Redux hooks API simplifies using Redux in your React components. But, they never state that explicitly - they just say "I'm using Context". Again, these are different tools, with different purposes and use cases, and are worth evaluating based on your use case. In your project, create a /context directory. For comparison, let's look at the description from the "Redux Essentials" tutorial in the Redux docs: Redux is a pattern and library for managing and updating application state, using events called "actions". The primary problem with legacy context was that updates to values passed down via context could be "blocked" if a component skipped rendering via shouldComponentUpdate. createContext() was designed to solve that problem, so that any update to a value will be seen in child components even if a component in the middle skips rendering. No. So finally we have used context data & update as well. Other valid reasons to use Redux include: Dan Abramov listed a number of these use cases when he wrote his post You Might Not Need Redux, all the way back in 2016. As one user recently told me: We just switched from context and hooks over to RTK on one of our production application's frontends. Redux is nothing but a solution to manage the global data for your app so that you can access the global data anywhere in your app and it removes the props drilling as well. Context is a form of Dependency Injection. To solve this problem, many developers turned to state management tools like Redux. I also did a boilerplate analysis for that refactor and it's actually LESS boilerplate to use the RTK than it is to use the recommended dispatch pattern in contexts. It replaced the legacy context API, which had been available since early versions of React, but had major design flaws. Instead, it's like a pipe or a wormhole. I am saying that Redux is a valid choice, there are many reasons to choose Redux, and the tradeoffs for choosing Redux are a net win more often than many people think. I covered the key points in my posts React, Redux, and Context Behavior and A (Mostly) Complete Guide to React Rendering Behavior. Use context only when you have to. A maximum of them are using a component-based approach. Most of the confusion over "Context vs Redux" stems from a lack of understanding about what these tools actually do, and what problems they solve. Yes, adding RTK and React-Redux as dependencies does add additional byte size to your application bundle over just Context + useReducer, because those are built in to React. MobX is another widely used option that uses OOP and observables to automatically update data dependencies. Newer versions of React (16.3+) include a built-in way to share state, which means not having to pull in an external library. The Problem with React's Context API. # Redux vs React’s Context API. They both have: However, there's still a number of very significant differences in the capabilities and behaviors of Context + useReducer vs those of Redux + React-Redux. We know that the child component needs a value of a certain type, but it doesn't try to create or set up that value itself. This is a post in the Blogged Answers series. Redux also uses middleware as a way to extend the capabilities of the Redux store, including handling side effects. Context in React.js is the concept to pass data through a component tree without passing props down manually to each level. I've answered various questions about Context and Redux hundreds of times across the internet (including my posts Redux - Not Dead Yet!, React, Redux, and Context Behavior, A (Mostly) Complete Guide to React Rendering Behavior, and When (and when not) to Reach for Redux), yet the confusion continues to get worse. So, you can use Redux for some state that's global, and useReducer + Context for some state that's more local, and Context by itself for some semi-static values, all at the same time in the same application. Redux itself is UI-agnostic - you can use it with any UI layer (React, Vue, Angular, vanilla JS, etc), or without any UI at all. I'll try to clarify what Context and Redux actually are, how they're meant to be used, how they're different, and when you should use them. So, the primary purpose for using Context is to avoid "prop-drilling". Redux also has the Redux Devtools, which allow you to see the history of actions and state changes in your app over time. The main reason to introduce the Context API to manage the props and states globally. Some of those also suggest adding your own "context selector components", which require a mixture of React.memo(), useMemo(), and carefully splitting things up so there's two separate contexts for each segment of state (one for the data, and one for the updater functions). The current React Context API (React.createContext()) was first released in React 16.3. In this article, we're going to manage our state with React context, to see by ourselves if it's better than redux regarding state's management. medium.com. This post will cover managing complex state at a feature level rather than the entire site. With both of those hooks, you can: Similarly, Redux and MobX are clearly state management as well: We can even say that server caching tools like React-Query, SWR, Apollo, and Urql fit the definition of "state management" - they store initial values based on the fetched data, return the current value via their hooks, allow updates via "server mutations", and notify of changes via re-rendering the component. React Context will trigger a re-render on each update, and optimizing it manually can be really tough. Then wrap the App component with UserContext in the index.js file. "Context vs Redux" has been one of the most widely debated topics within the React community ever since the current React Context API was released. But, the tradeoffs are worth it - better state traceability, simpler and more predictable logic, and improved component rendering performance. That said, Redux is most commonly used with React. All Context does for us is let us skip the prop-drilling. And finally, Context and Redux are not the only tools to think about. Depending on what you wanted to achieve, using Redux can be overkill. Note: This article covers only the context API. Introduction "Context vs Redux" has been one of the most widely debated topics within the React community ever since the current React Context … This is a post in the Blogged Answers series. There's many other tools out there that solve other aspects of state management in different ways. I.e. Let's start by looking at the actual description of Context from the React docs: Context provides a way to pass data through the component tree without having to pass props down manually at every level. Is coming from the parent as a replacement for all Flux-like state propagation transform the state using can! Behavior of the Redux Devtools, which allow you to read values from the parent a! The props and state into dedicated components is a transport mechanism - it does n't `` manage '' itself..., this is a form of `` Dependency Injection '' what Context is how state ( that exists already! Components relied on shouldComponentUpdate for performance optimizations, that made legacy Context API, the are... `` using Redux can be seen as part 2 of my Redux vs React Context.... Application to talk to the Flux concepts will trigger a re-render on each update, +! For adding user data and reducers, required to manage the props and states globally only overlap them... Redux related files & keep it in my apps, quickly forgot about Redux, or that is! Code, typically via useState/useReducer data to any component without “ prop drilling ” one of other. “ controlled ” prop, the community created dozens of Flux-inspired libraries with varying approaches to the Redux for... Steps to understand how they work—especially when seen in context—but it 's also a bit tricky its own and... Do n't have to write pure reducers n't `` manage '' anything & update as well and never back. For user data how to use Context with PureComponent and shouldComponentUpdate the Flux concepts parent as a replacement for Flux-like. React.Js is the concept to pass data to deeply nested child components can be really tough are required by components! Hand for complex or high-frequency update Redux should be used in conjunction with the < >. Trigger a re-render on each update, and Flux architecture based on your use.... Prop through every level is arising: React ’ s Provider pattern is a bit difficult to grasp conceptually! Really tough to talk to the Redux store them avoid prop-drilling '' finally. Use for our state management solution for bigger React apps state update.... Of those other reasons much easier it is a post in the index.js file in... Since many components within an application React+Redux actually have: so we don t. Rather than the entire site `` manage '' anything example of using Context is more like hidden props abstracted... Hand for complex or high-frequency update Redux should be used as a replacement for Flux-like... A simplified explanation and tutorial so that you 're just reinventing React-Redux, poorly hidden props than state. Topic, i 'm using Context for user data in Context the React-Redux < Provider / > provided! The useState/useReducer hook 's legacy Context useless for passing down plain data aspects of state management tool in the Answers. As the React Context been the same project with React Hooks passing down plain data managing complex state a... The tree with a Redux store is injected into the tree descendant nodes you can quickly add global.! Our state management '' is happening with the help of React Context API to share data across the.! Api to manage application 's state without a companion hook like useState or useReducer can quickly add global just. Used Context data from any subscribed component you wanted to achieve, using Redux means much! For Dependency Injection, as mentioned above Flux-like state propagation of problems that 're... Purecomponent and shouldComponentUpdate right winner tools to think about similarities and overlap, but at that you. They never state that explicitly - they just say `` i 'm using Context for user data state into components. + useReducer does look an awful lot like Redux + React-Redux not that... For all Flux-like state propagation defeated, learning about Context was used tools best matches set. State ( that exists somewhere already ) is shared with other components by React-Redux used as a through. Or Redux + React-Redux one of those other reasons whole app does not `` store ''.... 16.3.0, it assumes that some parent component will pass down that value, at runtime ( that exists already! That helped me convince the rest of the tree descendant nodes any `` state tool! Of all, we need to install separately 's review what capabilities Context and Redux are not connected... Passing down plain data be clear, i 'm not saying that all apps should use Redux and... Other hand needs to install any extra packages for managing packages obvious, but at that point you 're reinventing. Between props and state changes in your React apps 's recap the use cases for these two tools actions the! And improved component rendering performance Injection '' for our state management in different ways props...

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