Add useAutoClosingTag option

[dev-boku]

Summary

• I suggest the useAutoClosingTag option to fix the git issue below.

Reference

• Escaping input with unclosed, invalid tags returns it with unneeded escaped closing tags appended to end #464

[abea]

@potter7050 Thanks for the contribution. On a style note, I would suggest calling this option autoCloseTags. I would also ask for documentation of the new feature in the README file.

The bigger issue is that setting useAutoCloseTag: false does not only disable closing unclosed tags. It also fails to close tags that are already closed in the markup. See this test:

    const wackyText = sanitizeHtml('<p>here\'s a string with a <wacky> tag.</p>', {
      useAutoClosingTag: false,
      disallowedTagsMode: 'escape'
    });
    assert.equal(wackyText, '<p>here\'s a string with a &lt;wacky&gt; tag.</p>');

This fails with output <p>here's a string with a &lt;wacky&gt; tag..

Here we have a closed paragraph tag with an unclosed fake tag. The fake tag isn't closed, but the paragraph tag isn't closed either. If we were to call this closeTags: false, this would no longer be serving to sanitize HTML.

A fix for the original problem would need to

1. Recognize that a tag is not recognized (disallowed). If recognized, there should be no change.
2. Identify if the unrecognized tag is already closed in the input. If it is already closed, there should be no change.
3. Finally, if the tag is not recognized and it is not already close, then it can skip the closing tag.

As I mentioned in #464, I think the difficulty here is that htmlparser2 automatically tries to close these tags. It doesn't provide a signal (that I'm aware of) that the tag wasn't already closed.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.