Why is `location.state` null when navigating with React Router’s `Link` component?

Navigating through different components in a React application using the react-router-dom package allows for a smooth and dynamic user experience. In particular, passing state from one component to another during navigation can be extremely useful for carrying over data without the need for global state management tools or props drilling. However, it seems I’ve encountered a hiccup where the location.state is returning as null in the destination component, despite seemingly proper implementation.

Let’s break down the issue and explore potential fixes through an examination of the code fragments and React Router’s features.

Exploring the About Component’s Code

Here’s a snapshot of the code in my About component where I am trying to create a link for each item in an array with an id passed as part of the link’s state:

{items.map(item => (
  <div key={item.id} className="px-3">
    <div className="card card-body cards-aboutUs-Landing">
      <img className="img-fluid StateLogo" src={item.src} alt={`Slide ${item.id}`} />
      <div className="orgNameDiv"><p className="card-title OrgName">{item.name}</p></div>
      <button className="custom-btn orgDetailsBtn">
        <Link to={{pathname: '/state', state: {stateId: item.id}}}><span>Read More</span></Link>
      </button>
    </div>
  </div>
))}

Correcting the Link Placement

The primary issue here is the placement of the <Link> tag inside a <button> element. What happens is that when the button containing the link is pressed, the default button behavior may interfere with the link’s navigation functionality. This means the state may not be correctly passed or the navigation may not occur at all.

The fix should be relatively simple. We can convert the button itself into a clickable link by styling the <Link> to look like a button, rather than nesting it inside a <button> element. Here’s how you can modify the existing code:

{items.map(item => (
  <div key={item.id} className="px-3">
    <div className="card card-body cards-aboutUs-Landing">
      <img className="img-fluid StateLogo" src={item.src} alt={`Slide ${item.id}`} />
      <div className="orgNameDiv"><p className="card-title OrgName">{item.name}</p></div>
      <Link to={{ pathname: '/state', state: {stateId: item.id} }} className="custom-btn orgDetailsBtn">
        <span>Read More</span>
      </Link>
    </div>
  </div>
))}

In this revised code, Link from react-router-dom replaces the <button> tag, ensuring that when the “Read More” text is clicked, it behaves as a link and successfully passes the state without interference from button behavior.

Accessing State in the State Component

Reviewing how you’re accessing the state in your State component, your code looks perfectly valid:

let location = useLocation();
let stateId = location.state ? location.state.stateId : 'defaultStateId';
console.log(stateId);

This approach should function correctly provided the state is successfully passed. After making the changes above to the About component, this component should now properly receive the stateId.

Final Thoughts

It’s crucial to understand how certain HTML elements interact with React components, especially in complex libraries like react-router-dom. Incorrect nesting of components or misuse of HTML elements can lead to unexpected behavior, as seen where a button disrupts a link’s functionality. Always ensure that interactive React Router elements like Link are not enclosed in other interactive elements unless explicitly necessary and managed carefully. By adjusting the component structure as mentioned, we should see the desired functionality restored.