Note: Since I use Shiki and Twoslash I recommend you check out the blog post on the original site to get the full experience. TypeScript Snippets in Astro: Show, Don't Tell

Want smarter code snippets on your Astro site? This guide shows you how to add TypeScript type info that appears on hover. No fluff, just the steps you need. Your readers will thank you.

Before You Start

Set up an Astro project. Need help? See the Astro quickstart guide.

Set Up Shiki for Syntax Highlighting

Astro includes Shiki. Let's configure it:

Edit astro.config.mjs:

import { defineConfig } from "astro/config";

export default defineConfig({
  markdown: {
    shikiConfig: {
      themes: { light: "min-light", dark: "tokyo-night" },
    },
  },
});

Add a border to code blocks in your CSS:

pre:has(code) {
  @apply border border-skin-line;
}

Add Twoslash for Type Information

Install packages:

npm i -D twoslash twoslash-vue

Update astro.config.mjs:

import { createTransformerFactory, rendererRich } from '@shikijs/twoslash/core'
import { createTwoslasher } from 'twoslash-vue'
import { defineConfig } from "astro/config";

export default defineConfig({
  markdown: {
    shikiConfig: {
      themes: { light: "min-light", dark: "tokyo-night" },
      transformers: [
        createTransformerFactory(createTwoslasher())({
          langs: ['ts', 'tsx', 'vue'],
          renderer: rendererRich({
            lang: 'ts',
          }),
        }),
      ],
    },
  },
});

Use Interactive Snippets

Create TypeScript snippets in Markdown:

The // ^? shows where type info appears on hover.

Vue snippets work too:

For autocompletion, use ^|:

const increment = () => {
  count.v
  //    ^|
}

What You've Gained

Your Astro site now has:

Syntax highlighting
Hover-over type info
Light/dark mode code blocks

Your readers will thank you.