Resolving React State Issues with Typescript Classes in Your React Application

Discover how to effectively manage state in your React application when using a Typescript class for player control. Learn to ensure your components rerender properly.
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Resolving React State Issues with Typescript Classes in Your React Application

When building React applications, developers often encounter challenges, especially when integrating Typescript classes. One common problem is managing the state effectively when it relies on class instances, such as a player object. In this guide, we’ll explore a scenario where this issue arises and provide a comprehensive solution to ensure that your components rerender appropriately using local React state.

The Problem

Consider a function component named Player, which manages a SpotifyPlayer instance as part of its state. The component renders a child component, SongControls, responsible for displaying whether the player is currently playing or paused based on a boolean value, isPlaying. Here's how the component looks:

[[See Video to Reveal this Text or Code Snippet]]

The SongControls component then checks the isPlaying value to determine which control button to render (Play or Pause). However, there’s an issue: when the togglePlay() function is called, the React component does not rerender. This is because the instance of SpotifyPlayer isn’t changing, and React does not know it needs to update the UI.

Why This Happens

The main reasons React doesn’t rerender in this situation are:

Direct State Updates: Mutating the internal state of a class does not trigger the component lifecycle methods like rerenders in React.

Prototype Loss: If we attempt to update the spotifyPlayer state incorrectly using JavaScript destructuring, we could lose the prototype, and any methods defined in the class would become unavailable.

The Solution

To efficiently manage the state of your SpotifyPlayer within a React function component, you can follow this structured approach:

Step 1: Use useRef to Maintain a Consistent Player Instance

To ensure you have a consistent reference to the SpotifyPlayer object, use the useRef hook. This enables you to keep a single instance of your player across re-renders without losing its methods.

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Create Local State for isPlaying

Instead of relying on the class instance’s internal state, create a local state variable for isPlaying. You can set its initial value based on the spotifyPlayer:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Synchronize isPlaying with the Player

You can keep the state in sync using the useEffect hook. This will ensure that whenever the value of isPlaying changes, it updates the player’s state accordingly:

[[See Video to Reveal this Text or Code Snippet]]

Step 4: Update the Toggle Function

You can also handle the state update directly within the togglePlay function, which simplifies the handling of changes:

[[See Video to Reveal this Text or Code Snippet]]

Final Code Structure

With these changes, your Player component should look like this:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By maintaining a consistent reference to your SpotifyPlayer instance with useRef and managing the playing state with React’s local state, you can resolve rerender issues within your React components. This method allows your application to respond dynamically to user interactions, ensuring a smooth and efficient user experience.

We hope this helps you tackle similar challenges in your React and Typescript projects. If you have any more questions, feel free to leave a comment below!