Introduction

When working on a React, React Native, or Next.js project, state management across components can be a challenging task. React Context can be a powerful tool to simplify this process by allowing you to share the state without passing props down through multiple layers of components. Additionally, Custom Hooks can be used to encapsulate stateful logic and share it across multiple components, helping to avoid code duplication and simplify state management.

While React Context and Custom Hooks can be effective, they may not always provide the best performance or scalability, an alternative solution is Zustand.

Zustand* is a state management library that simplifies state management with hooks, improves performance with memoization, and provides flexibility in updating the state.*

In this article, we will explore how Zustand can be used in a ReactJs project to simplify state management and improve performance. We will also compare Zustand to React Context and Custom Hooks to help you determine the best solution for your project.

The problems with React Context

While React Context is a useful tool for sharing the state between components in a ReactJs project, it can lead to issues when misused. One problem is the potential for infinite re-rendering, which can cause the app to become unresponsive or crash.

One common cause of infinite rendering states with contexts is using a context value that depends on the component's own state or props. For example, in the code snippet below, the MyComponent sets the value of count using the useState hook and passes it down to the ChildComponent using the context value. If the value of count changes, the component will re-render, which will also trigger a re-render of ChildComponent. However, because the context value also depends on count, this will cause ChildComponent to re-render again, resulting in an infinite loop of re-renders.

const MyContext = createContext();

function MyComponent() {
  const [count, setCount] = useState(0);
  const contextValue = useMemo(() => ({ count }), [count]);

  return (
    <MyContext.Provider value={contextValue}>
      <div>
        <h1>Count: {count}</h1>
        <ChildComponent />
        <button onClick={() => setCount(count + 1)}>Increment Count</button>
      </div>
    </MyContext.Provider>
  );
}

function ChildComponent() {
  const { count } = useContext(MyContext);
  return <div>Count from context: {count}</div>;
}

Another issue with React Context is the difficulty of managing complex state. As the state grows more complex, it can be challenging to update the state correctly and efficiently. Additionally, React Context does not provide built-in support for memorization, which can lead to unnecessary re-renders and negatively impact performance. Finally, updating the state using React Context can be inflexible and require extra boilerplate code.

Drawbacks of state management with hooks

1. Every time a hook is initialized in a React component, a new instance of the hook is created, causing it to occupy space. This can become an issue as the project scales up.

2. As the application grows, state management with hooks and custom hooks can become complex and difficult to maintain. Developers must ensure that the state is correctly passed down to child components and that components are only re-rendered when necessary.

3. Depending on how the state is managed, there can be performance issues. For example, if the state is passed down to multiple child components, each component will need to re-render even if the state has not changed.

4. State management with hooks and custom hooks can lead to inconsistent behavior if not implemented correctly. For instance, if multiple components are sharing the same state, changes made to the state in one component may not be reflected in another component.

5. Debugging state management with hooks and custom hooks can be more challenging than traditional state management approaches, as it can be difficult to trace the flow of state changes through the application.

The benefits of Zustand

Zustand offers several benefits over using React Context for state management. First, Zustand provides a simpler and more lightweight API compared to Redux. You can define a global store using a simple function, and update the state using methods like getState, setState, and subscribe. This makes it easier to manage the state without adding unnecessary complexity to your codebase.

Another major benefit of Zustand is that it solves the problem of unnecessary re-renders caused by using Contexts. When using Contexts, any changes to the context object will cause all components that depend on that context to re-render, even if the state they care about hasn't actually changed. This can lead to performance issues, especially in larger applications.

In contrast, Zustand only updates components that are subscribed to relevant state changes, thanks to its use of closure and proxy objects. Zustand creates a closure around the initial state object and the functions that modify it. Whenever you call setState, Zustand updates the state object within the closure and notifies any subscribers that the state has changed. This allows React to know that it needs to re-render only the components that depend on that state.

Zustand uses proxy objects to provide a more efficient way to update the state. When you call setState with an object containing new state values, Zustand creates a new proxy object that wraps around the old state object. This proxy object only tracks changes to the state that were actually updated, rather than creating a completely new state object each time. This improves performance by reducing the number of unnecessary re-renders.

How to implement Zustand

To implement Zustand in a component, we need to define a global store using Zustand's create function and access it in the component using the useStore hook. Here's an example:

import create from 'zustand';

const useDataStore = create((set) => ({
  data: [],
  fetchData: () => {
    fetch("/api/data")
      .then((response) => response.json())
      .then((data) => set({ data }))
      .catch((error) => console.log(error));
  },
}));

function MyComponent() {
  const fetchData = useDataStore((state) => state.fetchData);
  const data = useDataStore((state) => state.data);

  useEffect(() => {
    fetchData();
  }, []);

  return (
    <MyContext.Provider value={data}>
      <ChildComponent />
    </MyContext.Provider>
  );
}

In this example, we define a global store using create with two properties: data and fetchData. The fetchData function uses async/await to fetch data from the API and updates the store's data property using the set function provided by Zustand.

In the MyComponent function, we access the fetchData and data properties using the useDataStore hook provided by Zustand. We then call fetchData in the useEffect hook to fetch data from the API when the component mounts.

By using Zustand, we can ensure that our data is only fetched once and avoid the risk of creating infinite re-rendering states. Additionally, because Zustand uses a lightweight proxy for the state, it provides better performance than using a context or Redux for state management.

Comparison between React Context and Zustand

React Context and Zustand are both state management libraries for React applications, but they differ in their approach and performance. React Context uses a provider-consumer model to pass state down the component tree, and any changes to the context value can cause all dependent components to re-render, even if their state has not changed. Zustand, on the other hand, uses a functional programming approach with closure and proxy objects to manage state. It creates a global store that can be accessed from anywhere in the app, and only updates components that are subscribed to the relevant state changes, avoiding unnecessary re-renders. Additionally, Zustand's use of proxies provides a more efficient way to update state compared to creating new state objects each time, resulting in better performance.

Conclusion

In conclusion, switching to Zustand has proven to be a great decision for many developers due to its lightweight and efficient approach to state management in React applications. Zustand's functional programming approach, use of closures and proxies, and simple API make it easier to manage and update the application state without causing unnecessary re-renders or performance issues.

Additionally, the ability to define a global store and access it from anywhere in the app, coupled with the fact that the store is not tied to any component, reduces the risk of creating infinite re-rendering states. All of these factors contribute to a more streamlined and optimized development process, which ultimately leads to a better user experience and more successful projects.