Add targetBlank option

[Tarocch1]

Description

Add targetBlank option. If true, open all links in new windows. Default is false.

marked.setOptions({
  targetBlank: true
});
marked('[test](/url/)');

Result

<p><a href="/url/" target="_blank">test</a></p>

Contributor

• Test(s) exist to ensure functionality and minimize regression (if no tests added, list tests covering this PR); or,
• no tests required for this PR.
• If submitting new feature, it has been documented in the appropriate places.

Committer

In most cases, this should be a different person than the contributor.

• Draft GitHub release notes have been updated.
• CI is green (no forced merge required).
• Merge PR

[styfle]

Hi @Tarocch1 thanks for the PR

We are actually trying to avoid adding new options to marked if it can be achieved with a sanitizer.

This PR overlooks the fact that the user may want to add a rel attribute or any number of sanitization techniques.

This feature can be achieved using sanitize-html like so:

       const sanitize = require('sanitize-html');
       const cleanHtml = sanitize(dirtyHtml, {
            allowedTags: [ 'a', 'b', 'p', 'i',  'em' ],
            allowedAttributes: {
                'a': ['href', 'target', 'rel'],
            },
            transformTags: {
                'a': (tagName, attribs) => {
                    if (attribs) {
                        attribs.target = '_blank';
                        attribs.rel = 'noopener noreferrer';
                    }
                    return { tagName, attribs };
                }
            },
        });

We actually have a proposal to remove sanitization in #1232

[UziTech]

This has already been proposed many times. As @styfle mentioned we are trying to avoid adding new options to prevent feature creep.

You can extend marked's renderer to add attributes to the a tag:

var renderer = new marked.Renderer();
renderer.link = function(href, title, text) {
    var link = marked.Renderer.prototype.link.apply(this, arguments);
    return link.replace("<a","<a target='_blank'");
};

marked.setOptions({
    renderer: renderer
});