@shikijs/rehype - "30 instances have been created"

[babakfp]

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• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.

Describe the bug

Hi 👋

[Shiki] 30 instances have been created. Shiki is supposed to be used as a singleton, consider refactoring your code to cache your highlighter instance; Or call `highlighter.dispose()` to release unused instances.

Yes, this is not a bug, but I don't understand how someone can use @shikijs/rehype without hitting into this issue.

I'm using this plugin in my website https://github.com/babakfp/babakfp.ir and in this preprocessor https://github.com/babakfp/mdx-svelte. Svelte loops through all markdown files, and inside that loop I use the unified stuff and rehype shiki.

Maybe it can be made in a way that I can create an instance outside the preprocess function and pass that to @shikijs/rehype via an option?

import { createHighlighter } from "@shikijs/rehype"

const highlighterInstance = createHighlighter()

processor.use(rehypeShiki, { highlighterInstance })

Reproduction

https://github.com/babakfp/babakfp.ir

Contributes

• I am willing to submit a PR to fix this issue
• I am willing to submit a PR with failing tests

[xarthurx]

Same problem here.
Using markdown-it as a plugin for nuxt3.

import mdShiki from "@shikijs/markdown-it";

  const renderer = MarkdownIt({
    linkify: true,
    html: true,
  })
    .use(mdFootnote)
    .use(
      await mdShiki({
        themes: {
          light: "snazzy-light",
          dark: "nord",
        },
      }),
    )

[boidushya]

Facing the same issue with @shikijs/rehype

[antfu]

@babakfp I am sorry, where is your related code in your reproduction?

[antfu]

About this warning in general, ideally you should avoid creating new rehype instance in a loop. For everyone who encountered this warning, please review your usage and see if there is a refactor you could make. Also share your usage and fix here, so we could have a better understanding of how people are using it, and potentially improve the docs.

[babakfp]

@babakfp I am sorry, where is your related code in your reproduction?

Sorry about that.

I made a proper reproduction here: https://github.com/babakfp/shikijs-shiki-issues-714

Watching this video may be helpful.

2024-07-02.17-45-24.mp4

It seems like the message only shows up on every second or third restart of the server. When just running pnpm dev, it doesn't show up. If you do (ctrl + s) after that, it still doesn't show up. If you do it again, it shows up.

In my https://github.com/babakfp/babakfp.ir project, it happens after running pnpm dev. Maybe something is wrong with my code that Vite/SvelteKit auto restarts the server, and it triggers the message.

2024-07-02.17-59-36.mp4

[antfu]

Thanks, I see it better now. If in unified, the plugin are supported to be used in a factory function, I think that would make sense for us to use the shared singleton instance by default. Made the change in c4f030d.