Understanding How to Properly Update and Display State in React useState Hook

Learn how to effectively update and display state in React using the `useState` hook to prevent issues with stale values.
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How to Properly Handle React State and Display Updated Values

React's useState hook is crucial for managing state in functional components. However, it's not uncommon to run into issues when trying to update state and subsequently display the new values. In this guide, we will tackle a common problem faced by many developers: updating a state value and displaying that updated value in an input field. Let’s start with the problem and then dive into the solution.

The Problem: Updating State in React

Imagine you have an application where users can leave reviews for items. You want to allow users to edit their reviews, which involves loading the last review into a text input, updating that text when the user types, and then saving the new review when they submit it.

Here’s a common scenario that developers encounter:

You initialize your state to hold the review text and timestamp.

You set up a mechanism to update that state when a user types in the input field.

After submitting the review, you try to update the state with the new values but find that the old values are still being displayed.

This can be frustrating, especially when you're implementing features that should be straightforward!

The Solution: Control Your Inputs with value

To ensure that your input field displays the updated value, it's crucial to control your input properly. Instead of using defaultValue, you should use the value attribute. Let’s break this down into actionable steps:

Step 1: Update Your Input Control

In the EditableText component, switch from using defaultValue to value. This makes your input a controlled component, which means it always reflects the current state.

Here's how you should modify your component:

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

Step 2: Handle User Input Correctly

Sometimes, the onChange event may not trigger for every key press due to how the EditableText component is implemented. If that’s the case, you can add an onKeyUp event:

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

This ensures that your state updates every time a key is released, guaranteeing the input reflects the latest user changes.

Step 3: Updating the State After Submission

When you successfully save the new review, you should also update the state with the new data returned from your submission. This is typically done in your submit function, like so:

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

Conclusion

By following these guidelines, you can efficiently manage and display updated states in your React components. Always remember to:

Use value instead of defaultValue for controlled components.

Implement the onChange and potentially onKeyUp to ensure immediate feedback to users.

Update the state appropriately after successful submissions to reflect changes.

With these practices, you'll eliminate issues with stale state values, allowing you to create more dynamic and user-friendly applications. Happy coding!