vue-renderer-markdown

Fast, streaming-friendly Markdown rendering for Vue 3 — progressive Mermaid, streaming diff code blocks, and real-time previews optimized for large documents.

Why use it?

• Progressive Mermaid: diagrams render incrementally so users see results earlier.
• Streaming diff code blocks: show diffs as they arrive for instant feedback.
• Built for scale: optimized DOM updates and memory usage for very large documents.

Compared to traditional Markdown renderers

Traditional Markdown renderers typically convert a finished Markdown string into a static HTML tree. This library is designed for streaming and interactive workflows and therefore provides capabilities you won't find in a classic renderer:

• Streaming-first rendering: render partial or incrementally-updated Markdown content without re-parsing the whole document each time. This enables live previews for AI outputs or editors that emit tokens progressively.
• Streaming-aware code blocks and "code-jump" UX: large code blocks are updated incrementally and the renderer can maintain cursor/selection context and fine-grained edits. This enables smooth code-editing experiences and programmatic "jump to" behaviors that traditional renderers do not support.
• Built-in diff/code-stream components: show diffs as they arrive (line-by-line or token-by-token) with minimal reflow. This is ideal for streaming AI edits or progressive code reviews — functionality that is not available in plain Markdown renderers.
• Progressive diagrams and editors: Mermaid diagrams and Monaco-based previews update progressively and render as soon as they become valid.
• Smooth, interactive UI: the renderer is optimized for minimal DOM churn and silky interactions (e.g. streaming diffs, incremental diagram updates, and editor integrations) so UX remains responsive even with very large documents.

These features make the library especially suited for real-time, AI-driven, and large-document scenarios where a conventional, static Markdown-to-HTML conversion would lag or break the user experience.

🚀 Live Demo

Demo site — try large Markdown files and progressive diagrams to feel the difference.

Features

• ⚡ Ultra-High Performance: Optimized for real-time streaming with minimal re-renders and efficient DOM updates
• 🌊 Streaming-First Design: Built specifically to handle incomplete, rapidly updating, and tokenized Markdown content
• 🧠 Monaco Streaming Updates: High-performance Monaco integration with smooth, incremental updates for large code blocks
• 🪄 Progressive Mermaid Rendering: Diagrams render as they become valid and update incrementally without jank
• 🧩 Custom Components: Seamlessly integrate your Vue components within Markdown content
• 📝 Complete Markdown Support: Tables, math formulas, emoji, checkboxes, code blocks, and more
• 🔄 Real-Time Updates: Handles partial content and incremental updates without breaking formatting
• 📦 TypeScript First: Full type definitions with intelligent auto-completion
• 🔌 Zero Configuration: Drop-in component that works with any Vue 3 project out of the box

Install

pnpm add vue-renderer-markdown
# or
npm install vue-renderer-markdown
# or
yarn add vue-renderer-markdown

Install peer dependencies (important)

This package declares several peer dependencies. Some are required for core rendering and others are optional and enable extra features. Since the library now lazy-loads heavyweight optional peers at runtime, you can choose a minimal install for basic rendering or a full install to enable advanced features.

Minimal (core) peers — required for basic rendering:

pnpm (recommended):

pnpm add vue

Full install — enables diagrams, Monaco editor preview and icon UI (recommended if you want all features):

pnpm add vue @iconify/vue katex mermaid vue-use-monaco

npm equivalent:

npm install vue @iconify/vue katex mermaid vue-use-monaco

yarn equivalent:

yarn add vue @iconify/vue katex mermaid vue-use-monaco

Notes:

• The exact peer version ranges are declared in this package's package.json — consult it if you need specific versions.
• Optional peers and the features they enable:
  • mermaid — enables Mermaid diagram rendering (progressive rendering is supported). If absent, code blocks tagged mermaid fall back to showing the source text without runtime errors.
  • vue-use-monaco — enables Monaco Editor based previews/editing and advanced streaming updates for large code blocks. If absent, the component degrades to plain text rendering and no editor is created.
  • @iconify/vue — enables iconography in the UI (toolbar buttons). If absent, simple fallback elements are shown in place of icons so the UI remains functional.
• vue-i18n is optional: the library provides a synchronous fallback translator. If your app uses vue-i18n, the library will automatically wire into it at runtime when available.
• If you're installing this library inside a monorepo or using pnpm workspaces, install peers at the workspace root so they are available to consuming packages.

Why vue-renderer-markdown?

Streaming Markdown content from AI models, live editors, or real-time updates presents unique challenges:

• Incomplete syntax blocks can break traditional parsers
• Rapid content changes cause excessive re-renders and performance issues
• Cursor positioning becomes complex with dynamic content
• Partial tokens need graceful handling without visual glitches

vue-renderer-markdown solves these challenges with a streaming-optimized architecture that maintains perfect formatting and performance, even with the most demanding real-time scenarios.

Usage

Streaming Markdown (Recommended)

Perfect for AI model responses, live content updates, or any scenario requiring real-time Markdown rendering:

<script setup lang="ts">
import { ref } from 'vue'
import MarkdownRender from 'vue-renderer-markdown'

const content = ref('')
const fullContent = `# Streaming Content\n\nThis text appears character by character...`

// Simulate streaming content
let index = 0
const interval = setInterval(() => {
  if (index < fullContent.length) {
    content.value += fullContent[index]
    index++
  }
  else {
    clearInterval(interval)
  }
}, 50)
</script>

<template>
  <MarkdownRender :content="content" />
</template>

Basic Usage

For static or pre-generated Markdown content:

<script setup lang="ts">
import MarkdownRender from 'vue-renderer-markdown'

const markdownContent = `
# Hello Vue Markdown

This is **markdown** rendered as HTML!

- Supports lists
- [x] Checkboxes
- :smile: Emoji
`
</script>

<template>
  <MarkdownRender :content="markdownContent" />
</template>

Performance Features

The streaming-optimized engine delivers:

• Incremental Parsing Code Blocks: Only processes changed content, not the entire code block
• Efficient DOM Updates: Minimal re-renders
• Monaco Streaming: Fast, incremental updates for large code snippets without blocking the UI
• Progressive Mermaid: Diagrams render as soon as syntax is valid and refine as content streams in
• Memory Optimized: Intelligent cleanup prevents memory leaks during long streaming sessions
• Animation Frame Based: Smooth animations
• Graceful Degradation: Handles malformed or incomplete Markdown without breaking

Props

Name	Type	Required	Description
content	string	✓	Markdown string to render
nodes	BaseNode[]		Parsed markdown AST nodes (alternative to content)
renderCodeBlocksAsPre	boolean		When true, render all code_block nodes as simple <pre><code> blocks (uses PreCodeNode) instead of the full CodeBlockNode. Useful for lightweight, dependency-free rendering of multi-line text such as AI "thinking" outputs. Defaults to false.

Either content or nodes must be provided.

Note: when using the component in a Vue template, camelCase prop names should be written in kebab-case (for example, renderCodeBlocksAsPre -> render-code-blocks-as-pre).

New prop: renderCodeBlocksAsPre

• Type: boolean
• Default: false

Description:

• When set to true, all parsed code_block nodes are rendered as a simple <pre><code> (the library's internal PreCodeNode) instead of the full CodeBlockNode which may depend on optional peers such as Monaco or mermaid.
• Use case: enable this when you need lightweight, preformatted text rendering (for example AI "thinking" outputs or multi-line reasoning steps) and want to avoid depending on optional peer libraries while preserving original formatting.

Notes:

• When renderCodeBlocksAsPre: true, props passed to CodeBlockNode such as codeBlockDarkTheme, codeBlockMonacoOptions, themes, minWidth, maxWidth, etc. will not take effect because CodeBlockNode is not used.
• If you need the full code block feature set (syntax highlighting, folding, copy button, etc.), keep the default false and install the optional peers (mermaid, vue-use-monaco, @iconify/vue).

Example (Vue usage):

<script setup lang="ts">
import MarkdownRender from 'vue-renderer-markdown'

const markdown = `Here is an AI thinking output:\n\n\`\`\`text\nStep 1...\nStep 2...\n\`\`\`\n`
</script>

<template>
  <MarkdownRender :content="markdown" :render-code-blocks-as-pre="true" />
</template>

Advanced

Custom Components

Instead of passing a customComponents prop, the library exposes a runtime API to override node component mappings globally. Import setCustomComponents from the package and call it during app initialization (for example in your main.ts) to provide a mapping of node names to Vue components.

Example (global replacement):

import { createApp } from 'vue'
import MarkdownRender, { setCustomComponents } from 'vue-renderer-markdown'
import App from './App.vue'
import MyCustomNode from './components/MyCustomNode.vue'

const app = createApp(App)

// Provide a mapping of node keys to components. Keys match the internal node names
// (for example: `admonition`, `code_block`, `image`, `math_block`, etc.).
setCustomComponents({
  admonition: MyCustomNode,
  // ...other overrides
})

app.mount('#app')

Notes:

• setCustomComponents applies globally to all MarkdownRender instances. Call it before mounting your app to ensure components are registered before rendering occurs.
• If you need per-instance overrides, you can still merge your mapping into the result of the getNodeComponents util in advanced setups (internal API) but the public supported approach is to use setCustomComponents.

TypeScript: Full type support. Import types as needed:

import type { MyMarkdownProps } from 'vue-renderer-markdown/dist/types'

ImageNode slots (placeholder / error)

ImageNode now supports two named slots so you can customize the loading and error states:

• Slot name: placeholder
• Slot name: error

Both slots receive the same set of reactive slot props:

• node — the original ImageNode object ({ type: 'image', src, alt, title, raw })
• displaySrc — the current src used for rendering (will be fallbackSrc if a fallback was applied)
• imageLoaded — boolean, whether the image has finished loading
• hasError — boolean, whether the image is in an error state
• fallbackSrc — string, the fallback src passed to the component (if any)
• lazy — boolean, whether lazy loading is used
• isSvg — boolean, whether the current displaySrc is an SVG

Default behavior: if you don't provide the slots the component shows a built-in CSS spinner for placeholder and a simple error placeholder for error.

Example: customize loading and error slots

<ImageNode :node="node" :fallback-src="fallback" :lazy="true">
  <template #placeholder="{ node, displaySrc, imageLoaded }">
    <div class="p-4 bg-gray-50 rounded shadow-sm flex items-center justify-center">
      <div class="animate-pulse w-full h-24 bg-gray-200"></div>
      <span class="sr-only">Loading image</span>
    </div>
  </template>

  <template #error="{ node, displaySrc }">
    <div class="p-4 text-sm text-red-600 flex items-center gap-2">
      <strong>Failed to load image</strong>
      <span class="truncate">{{ displaySrc }}</span>
    </div>
  </template>
</ImageNode>

Tip: to avoid layout shift when switching from placeholder to the image, keep the placeholder's width/height similar to the final image (or use aspect-ratio / min-height). This lets the image fade/transform without triggering layout reflow.

LinkNode: underline animation & color customization

LinkNode (the internal node used to render anchors) now supports runtime customization of underline animation and color via props — no need to override global CSS. Defaults preserve the previous appearance.

Available props (pass to the component that renders LinkNode):

Name	Type	Default	Description
color	string	#0366d6	Link text color (any valid CSS color). The underline uses currentColor, so it follows this color.
underlineHeight	number	2	Underline thickness in pixels.
underlineBottom	number | string	-3px	Offset from the text baseline; accepts px or any CSS length (e.g., 0.2rem).
animationDuration	number	0.8	Total animation duration in seconds.
animationOpacity	number	0.9	Underline opacity.
animationTiming	string	linear	CSS timing function (e.g., linear, ease, ease-in-out).
animationIteration	string | number	infinite	Animation iteration count or 'infinite'.

Example:

<template>
  <!-- Default styling -->
  <LinkNode :node="node" />

  <!-- Custom color and underline styling -->
  <LinkNode
    :node="node"
    color="#e11d48"
    :underline-height="3"
    underline-bottom="-4px"
    :animation-duration="1.2"
    :animation-opacity="0.8"
    animation-timing="ease-in-out"
  />
</template>

Notes:

• The underline color uses currentColor, so by default it matches the color prop. If you need an independent underline color, consider a small local CSS override or opening an issue to discuss exposing an underlineColor prop.
• All props are optional; when omitted, sensible defaults are used to remain backward compatible.

Override Language Icons

Override how code language icons are resolved via the plugin option getLanguageIcon. This keeps your usage unchanged and centralizes customization.

Plugin usage:

import { createApp } from 'vue'
import { VueRendererMarkdown } from 'vue-renderer-markdown'
import App from './App.vue'

const app = createApp(App)

// Example 1: replace shell/Shellscript icon with a remote SVG URL
const SHELL_ICON_URL = 'https://raw.githubusercontent.com/catppuccin/vscode-icons/refs/heads/main/icons/mocha/bash.svg'
app.use(VueRendererMarkdown, {
  getLanguageIcon(lang) {
    const l = (lang || '').toLowerCase()
    if (
      l === 'shell'
      || l === 'shellscript'
      || l === 'sh'
      || l === 'bash'
      || l === 'zsh'
      || l === 'powershell'
      || l === 'ps1'
      || l === 'bat'
      || l === 'batch'
    ) {
      return `<img src="${SHELL_ICON_URL}" alt="${l}" />`
    }
    // return empty/undefined to use the library default icon
    return undefined
  },
})

Local file example (import inline SVG):

import { createApp } from 'vue'
import { VueRendererMarkdown } from 'vue-renderer-markdown'
import App from './App.vue'
import JsIcon from './assets/javascript.svg?raw'

const app = createApp(App)

app.use(VueRendererMarkdown, {
  getLanguageIcon(lang) {
    const l = (lang || '').toLowerCase()
    if (l === 'javascript' || l === 'js')
      return JsIcon // inline SVG string
    return undefined
  },
})

Notes:

• The resolver returns raw HTML/SVG string. Returning undefined/empty value defers to the built-in mapping.
• Works across all code blocks without changing component usage.
• Alignment: icons render inside a fixed-size slot; both <svg> and <img> align consistently, no inline styles needed.
• For local files, import with ?raw and ensure the file is a pure SVG (not an HTML page). Download the raw SVG instead of GitHub’s HTML preview.
• The resolver receives the raw language string (e.g., tsx:src/components/file.tsx). The built-in fallback mapping uses only the base segment before :.

Monaco Editor Integration

If you are using Monaco Editor in your project, configure vite-plugin-monaco-editor-esm to handle global injection of workers. Our renderer is optimized for streaming updates to large code blocks—when content changes incrementally, only the necessary parts are updated for smooth, responsive rendering. On Windows, you may encounter issues during the build process. To resolve this, configure customDistPath to ensure successful packaging.

Note: If you only need to render a Monaco editor (for editing or previewing code) and don't require this library's full Markdown rendering pipeline, you can integrate Monaco directly using vue-use-monaco for a lighter, more direct integration.

pnpm add vite-plugin-monaco-editor-esm monaco-editor -d

npm equivalent:

npm install vite-plugin-monaco-editor-esm monaco-editor --save-dev

yarn equivalent:

yarn add vite-plugin-monaco-editor-esm monaco-editor -d

Example Configuration

import path from 'node:path'
import monacoEditorPlugin from 'vite-plugin-monaco-editor-esm'

export default {
  plugins: [
    monacoEditorPlugin({
      languageWorkers: [
        'editorWorkerService',
        'typescript',
        'css',
        'html',
        'json',
      ],
      customDistPath(root, buildOutDir, base) {
        return path.resolve(buildOutDir, 'monacoeditorwork')
      },
    }),
  ],
}

Code block header customization

The code block component now exposes a flexible header API so consumers can:

• Toggle the entire header on/off.
• Show or hide built-in toolbar buttons (copy, expand, preview, font-size controls).
• Fully replace the left or right header content via named slots.

This makes it easy to adapt the header to your application's UX or to inject custom controls.

Props (new)

Name	Type	Default	Description
showHeader	boolean	true	Toggle rendering of the header bar.
showCopyButton	boolean	true	Show the built-in copy button.
showExpandButton	boolean	true	Show the built-in expand/collapse button.
showPreviewButton	boolean	true	Show the built-in preview button (when preview is available).
showFontSizeButtons	boolean	true	Show the built-in font-size controls (also requires enableFontSizeControl).

Slots

• header-left — Replace the left side of the header (language icon + label by default).
• header-right — Replace the right side of the header (built-in action buttons by default).

Example: hide the header

<CodeBlockNode
  :node="{ type: 'code_block', language: 'javascript', code: 'console.log(1)', raw: 'console.log(1)' }"
  :showHeader="false"
  :loading="false"
/>

Example: custom header via slots

<CodeBlockNode
  :node="{ type: 'code_block', language: 'html', code: '<div>Hello</div>', raw: '<div>Hello</div>' }"
  :loading="false"
  :showCopyButton="false"
>
  <template #header-left>
    <div class="flex items-center space-x-2">
      <!-- custom icon or label -->
      <span class="text-sm font-medium">My HTML</span>
    </div>
  </template>

  <template #header-right>
    <div class="flex items-center space-x-2">
      <button class="px-2 py-1 bg-blue-600 text-white rounded">Run</button>
      <button class="px-2 py-1 bg-gray-200 dark:bg-gray-700 rounded">Inspect</button>
    </div>
  </template>
</CodeBlockNode>

Notes

• The new showFontSizeButtons prop provides an additional toggle; the existing enableFontSizeControl prop still controls whether the font-size feature is enabled at all. Keep both in mind when hiding/showing font controls.
• Existing behavior is unchanged by default — all new props default to true to preserve the original UI.

This configuration ensures that Monaco Editor workers are correctly packaged and accessible in your project.

Webpack — monaco-editor-webpack-plugin

If your project uses Webpack instead of Vite, you can use the official monaco-editor-webpack-plugin to bundle and inject Monaco's worker files. Here's a minimal example for Webpack 5:

Install:

pnpm add -D monaco-editor monaco-editor-webpack-plugin
# or
npm install --save-dev monaco-editor monaco-editor-webpack-plugin

Example webpack.config.js:

const path = require('node:path')
const MonacoEditorPlugin = require('monaco-editor-webpack-plugin')

module.exports = {
  // ...your other config...
  output: {
    // Ensure worker files are placed correctly; adjust publicPath/filename as needed
    publicPath: '/',
  },
  plugins: [
    new MonacoEditorPlugin({
      // Limit to required languages/features to reduce bundle size
      languages: ['javascript', 'typescript', 'css', 'html', 'json'],
      // Optional: customize worker filename pattern
      filename: 'static/[name].worker.js',
    }),
  ],
}

Notes:

• For projects using monaco-editor, make sure the plugin handles the workers; otherwise the browser will try to load missing worker files at runtime (similar to Vite dep optimizer issues).
• If you see "file does not exist" errors after building (for example some workers are missing from the optimized deps directory), ensure the worker files are packaged into an accessible location via the plugin or build output.

Mermaid: Progressive Rendering Example

Mermaid diagrams can be streamed progressively. The diagram renders as soon as the syntax becomes valid and refines as more content arrives.

<script setup lang="ts">
import { ref } from 'vue'
import MarkdownRender from 'vue-renderer-markdown'

const content = ref('')
const steps = [
  '```mermaid\n',
  'graph TD\n',
  'A[Start]-->B{Is valid?}\n',
  'B -- Yes --> C[Render]\n',
  'B -- No  --> D[Wait]\n',
  '```\n',
]

let i = 0
const id = setInterval(() => {
  content.value += steps[i] || ''
  i++
  if (i >= steps.length)
    clearInterval(id)
}, 120)
</script>

<template>
  <MarkdownRender :content="content" />
  <!-- Diagram progressively appears as content streams in -->
  <!-- Mermaid must be installed as a peer dependency -->
</template>

Tailwind (e.g. shadcn) — fix style ordering issues

If your project uses a Tailwind component library like shadcn you may run into style ordering/override issues. We recommend importing the library CSS into a controlled Tailwind layer in your global stylesheet. For example, in your main stylesheet (e.g. src/styles/index.css or src/main.css):

/* main.css or index.css */
@tailwind base;
@tailwind components;
@tailwind utilities;

/* Recommended: place library styles into the components layer so your app components can override them */
@layer components {
  @import 'vue-renderer-markdown/index.css';
}

/* Alternative: place into the base layer if you want the library styles to be more foundational and harder to override:
@layer base {
  @import 'vue-renderer-markdown/index.css';
}
*/

Pick components (common) or base (when you want library styles to be more foundational) based on your desired override priority. After changing, run your dev/build command (e.g. pnpm dev) to verify the stylesheet ordering.

Thanks

This project is built with the help of these awesome libraries:

• vue-use-monaco — Monaco Editor integration for Vue
• shiki — Syntax highlighter powered by TextMate grammars and VS Code themes

Thanks to the authors and contributors of these projects!

Star History

License

MIT © Simon He