30-seconds-of-code/snippets/AutoLink.md

AutoLink

Renders a string as plaintext, with URLs converted to appropriate <a> elements.

Use String.prototype.split() and String.prototype.match() with a regular expression to find URLs in a string. Return a <React.Fragment> with matched URLs rendered as <a> elements, dealing with missing protocol prefixes if necessary, and the rest of the string rendered as plaintext.

function AutoLink({ text }) {
  const delimiter = /((?:https?:\/\/)?(?:(?:[a-z0-9]?(?:[a-z0-9\-]{1,61}[a-z0-9])?\.[^\.|\s])+[a-z\.]*[a-z]+|(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3})(?::\d{1,5})*[a-z0-9.,_\/~#&=;%+?\-\\(\\)]*)/gi;

  return (
    <React.Fragment>
      {text.split(delimiter).map(word => {
        let match = word.match(delimiter);
        if (match) {
          let url = match[0];
          return (
            <a href={url.startsWith("http") ? url : `http://${url}`}>{url}</a>
          );
        }
        return word;
      })}
    </React.Fragment>
  );
}

ReactDOM.render(
  <AutoLink text='foo bar baz http://example.org bar' />,
  document.getElementById('root')
);