Rendering HTML Strings as Real HTML in React

In React, rendering HTML strings as real HTML can be achieved using various methods. In this tutorial, we’ll explore the different approaches to render HTML strings, including the use of dangerouslySetInnerHTML, third-party libraries like react-html-parser and html-react-parser, and manual DOM manipulation.

Using dangerouslySetInnerHTML

The dangerouslySetInnerHTML attribute can be used to set the inner HTML of a React element. This method is called "dangerous" because it can expose your application to cross-site scripting (XSS) attacks if not used properly.

import React from 'react';

class App extends React.Component {
  render() {
    const htmlString = '<h1>Hello World!</h1>';
    return (
      <div dangerouslySetInnerHTML={{ __html: htmlString }} />
    );
  }
}

However, when using dangerouslySetInnerHTML, it’s essential to ensure that the HTML string is properly sanitized to prevent XSS attacks.

Using Third-Party Libraries

Libraries like react-html-parser and html-react-parser provide a safer way to render HTML strings as React components. These libraries parse the HTML string and convert it into React elements, avoiding the need to use dangerouslySetInnerHTML.

import React from 'react';
import parse from 'html-react-parser';

const App = () => {
  const htmlString = '<h1>Hello World!</h1>';
  return (
    <div>
      {parse(htmlString)}
    </div>
  );
};

Manual DOM Manipulation

Another approach is to use manual DOM manipulation by creating a reference to a DOM element and setting its innerHTML property.

import React, { useRef, useEffect } from 'react';

const App = () => {
  const spanRef = useRef(null);
  const [htmlString, setHtmlString] = useState('<h1>Hello World!</h1>');

  useEffect(() => {
    if (spanRef.current) {
      spanRef.current.innerHTML = htmlString;
    }
  }, [spanRef, htmlString]);

  return (
    <div>
      my custom text follows<br />
      <span ref={spanRef} />
    </div>
  );
};

However, when using manual DOM manipulation, it’s crucial to sanitize the HTML string to prevent XSS attacks.

Sanitizing HTML Strings

To prevent XSS attacks, it’s essential to sanitize the HTML strings before rendering them. Libraries like DOMPurify can be used to sanitize HTML strings.

import React from 'react';
import * as DOMPurify from 'dompurify';

const App = () => {
  const htmlString = '<h1>Hello World!</h1>';
  const sanitizedHtmlString = DOMPurify.sanitize(htmlString);

  return (
    <div dangerouslySetInnerHTML={{ __html: sanitizedHtmlString }} />
  );
};

In conclusion, rendering HTML strings as real HTML in React can be achieved using various methods. However, it’s essential to ensure that the HTML strings are properly sanitized to prevent XSS attacks.

Best Practices

• Always sanitize HTML strings before rendering them.
• Use third-party libraries like react-html-parser and html-react-parser for safer rendering of HTML strings.
• Avoid using dangerouslySetInnerHTML whenever possible.
• Use manual DOM manipulation with caution and ensure proper sanitization of HTML strings.