walkTokens and local context

[j3rem1e]

Hello,

I have implemented a plugin to transform some elements in the markdown using a "local context": Each markdown is parsed to html using a context linked to the markdown. For example, it transforms links or code blocks using properties of the parent component to contextualize some graphics or href.

In order to do that, I have to create a new Marked instance every time I want to parse the markdown.

My question is mainly about performances:

• Is it costly to create a Marked instance ? I'm worried about the parsing of the configuration of every plugins I need
• If it's costly, how to optimize the creation of instances ? (cloning ?)
• Can I implement a walkTokens using a context without creating a new Marked instance ?

Thanks!

[UziTech]

Is it costly to create a Marked instance?

I don't think we have any metrics on how costly it is to create a marked instance but it shouldn't be too costly.

If it's costly, how to optimize the creation of instances?

If each instance uses the same extensions you should be able to reuse the instance and just run marked.parse again.

Can I implement a walkTokens using a context without creating a new Marked instance?

Yes. WalkTokens does not have context of parent tokens, but you can create your own version of walk tokens that does.

Something like:

const tokens = marked.lexer(markdown);

// update tokens here

const html = marked.parser(tokens);

[j3rem1e]

If I call myself lexer/walk/parser, I have to reimplements some logics already handled by marked, like calling hooks, walkTokens of possible extensions, etc, no ?

[UziTech]

Yes. This is essentially how marked.parse works.

marked/src/Instance.ts

Lines 279 to 294 in ba3b7e4

	try {
	if (opt.hooks) {
	src = opt.hooks.preprocess(src) as string;
	}
	const tokens = lexer(src, opt);
	if (opt.walkTokens) {
	this.walkTokens(tokens, opt.walkTokens);
	}
	let html = parser(tokens, opt);
	if (opt.hooks) {
	html = opt.hooks.postprocess(html) as string;
	}
	return html;
	} catch (e) {
	return throwError(e as Error);
	}