How to Fix the substring Error on HTMLCollection in React Admin

Learn how to address the common `substring` error in React-admin when attempting to limit character display in your application. Discover the best practices for accessing and modifying DOM elements with React.
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How to Fix the substring Error on HTMLCollection in React Admin

If you're working with React-admin and notice that your data lists feature excessively long text, you may be looking for a solution to limit the character display. Specifically, you may have encountered the error message: Property 'substring' does not exist on type 'HTMLCollectionOf HTMLSpanElement '. This can create confusion when you're attempting to manipulate DOM elements.

In this guide, we will address this issue step-by-step, allowing you to efficiently display truncated text in your application.

Understanding the Problem

You might find yourself needing to truncate the length of text within multiple <span> elements in your React application. This is when you try to use the substring method on an HTMLCollection, which isn't directly accessible like an array. The error appears when you try to call substring on the spans variable, which is of type HTMLCollectionOf<HTMLSpanElement>, instead of an individual span's text content.

Proposed Solution

Let’s correct the approach and demonstrate how to effectively limit character display in your data list. Follow the step-by-step guidance below.

Step 1: Select the Spans

Instead of attempting to directly apply a substring method to the HTMLCollection, we'll convert it into an array format. This will allow us to iterate over each span's content easily.

Step 2: Iterate and Modify the Content

You'll want to loop through the spans and check the length of their text content. If it's greater than 50 characters, truncate it.

Step 3: Implement the Code

Here’s the corrected code using React's useEffect:

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

Code Breakdown

Converting to Array: const spansList = [...spans]; creates an array from the HTMLCollection, allowing us to use array methods.

Iterating Through Spans: Using a for...of loop, we can check each span's textContent.

Truncating Text: If a span's content exceeds 50 characters, we truncate it to 50 and add an ellipsis "...".

Conclusion

In summary, solving the substring error requires us to alter our approach to how we handle HTMLCollections in React. By converting the collection into an array, we gain access to the text content of each <span> and can effectively modify it as needed. This method not only resolves the error but also enhances the readability of your data lists.

With this guide, you can efficiently manage long text entries in React-admin and ensure a better user experience.