marked.use

[UziTech]

Marked version: master

Description

Add function marked.use which takes an options object and merges it into marked options.

The renderer and tokenizer can be an object with functions that will be merged into the renderer and tokenizer respectively.

The renderer and tokenizer functions can return false to fallback to the previous function.

const extension = {
	breaks: true,
	renderer: {
		html(html) {
			if (html.startsWith('<div')) {
				return html.replace(/</g, '&lt;').replace(/>/g, '&gt;');
			}
			return false;
		}
	}
};
marked.use(extension);
const html = marked(`
<div>
html renderer will use extension
</div>

<span>will fallback to regular html renderer</span>

options from extension
will be used.
`);
console.log(html);
/* will log:
&lt;div&gt;
html renderer will use extension
&lt;/div&gt;

<span>will fallback to regular html renderer</span>

<p>options from extension<br>will be used.</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

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[davisjam]

Looks good overall. Perhaps add a sentence in USING_PRO.md to clarify the use case?

[joshbruce]

I appreciate this solution, agree with @davisjam request for updates to docs, which seems to have happened.

Does this only work for a custom renderer at this time? Is this a reusable pattern for extending other sub-components of Marked?

[UziTech]

This can be used to extend any option in marked. The renderer and tokenizer will be merged but all other options will overwrite previous options.

[UziTech]

@davisjam I added a section explaining marked.use

[UziTech]

This PR doesn't change current ways of extending marked with marked.setOptions(options) or adding options as a second parameter to marked(md, options).

It just adds a new method (marked.use(options)) that will merge the tokenizer and renderer instead of overriding them completely. This method should be recommended over other ways of changing options and maybe in the future we can change other ways to merging them as well.

[davisjam]

LGTM, thanks

[UziTech]

The idea is to create extensions in the form

// some-marked-extension
module.exports = {
	renderer: {...},
	tokenizer: {...}
};

// some-other-marked-extension
module.exports = {
	renderer: {...},
	tokenizer: {...}
};

that can be used by users without overriding eachother

const marked = require('marked');
marked.use(require('some-marked-extension'));
marked.use(require('some-other-marked-extension'));
...

[styfle]

Great work 🎉