When working with React, you may encounter situations where you need to render HTML content as a string using dangerouslySetInnerHTML. This can be useful for rendering user-generated content, but it also introduces potential security vulnerabilities if the content is not properly sanitized.

In this article, we’ll explore how to truncate dangerouslySetInnerHTML in React using a function component.

Example Function Component

Here’s an example of a function component that takes in the HTML content and a maximum length, and renders the content truncated to the specified length:

function TruncatedHtml({ content, maxLength }) {
  if (content.length <= maxLength) {
    return <div dangerouslySetInnerHTML={{ __html: content }} />;
  }

  const truncatedContent = content.substring(0, maxLength) + '...';

  return <div dangerouslySetInnerHTML={{ __html: truncatedContent }} />;
}

Let’s break down how this function component works.

First, the component checks whether the length of the HTML content is less than or equal to the specified maximum length. If it is, the component simply renders the content using dangerouslySetInnerHTML.

If the length of the content is greater than the specified maximum length, the component truncates the content by using the substring method to extract a substring of the first maxLength characters, and then append an ellipsis at the end.

Finally, the component renders the truncated content using dangerouslySetInnerHTML.

Usage Example

Here’s an example of how to use the TruncatedHtml the component in your React application:

function App() {
  const content = '<p>This is some HTML content that needs to be truncated.</p>';
  const maxLength = 30;

  return <TruncatedHtml content={content} maxLength={maxLength} />;
}

In this example, we define a content variable that contains some HTML content that needs to be truncated, and a maxLength variable that specifies the maximum length of the truncated content. We then render the TruncatedHtml component and pass in the content and maxLength props.

When the TruncatedHtml component is rendered, it will truncate the content to the specified maxLength and render the truncated content using dangerouslySetInnerHTML.

Conclusion

In this article, we’ve explored how to truncate dangerouslySetInnerHTML in React using a function component. By truncating the HTML content before rendering it, we can reduce the risk of security vulnerabilities and improve the overall security of our React applications.

Keep in mind that truncating HTML content can result in incomplete tags or invalid HTML, which may cause rendering issues or unexpected behavior. Additionally, truncating the content may not address all potential security vulnerabilities that dangerouslySetInnerHTML can introduce, so it’s generally recommended to use safer alternatives, such as React’s built-in JSX syntax or a third-party library that provides safer HTML rendering.