D2 quick start

D2 diagrams render progressively in markstream-vue: as soon as the syntax becomes valid, a preview appears and keeps refining as more tokens stream in. If rendering fails, the last successful preview stays visible and the source is preserved.

1. Install & import

pnpm add @terrastruct/d2

No extra CSS import is required. Keep markstream-vue/index.css after your reset and inside @layer components if you use Tailwind/UnoCSS.

@import 'modern-css-reset';

@layer components {
  @import 'markstream-vue/index.css';
}

2. Streaming example

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

const content = ref('')
const steps = [
  '```d2\n',
  'direction: right\n',
  'Client -> API: request\n',
  'API -> DB: query\n',
  'DB -> API: rows\n',
  'API -> Client: response\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" />
</template>

Quick try — paste this Markdown into a page or component:

\`\`\`d2
direction: right
Client -> API: request
API -> DB: query
DB -> API: rows
API -> Client: response
\`\`\`

3. Advanced component: D2BlockNode

Use D2BlockNode if you want toolbar controls (copy/export/mode toggle) or to override themes and progressive timing.

<script setup lang="ts">
import type { D2BlockNodeProps } from 'markstream-vue'
import { D2BlockNode } from 'markstream-vue'

const node = {
  type: 'code_block',
  language: 'd2',
  code: 'direction: right\nClient -> API: request\nAPI -> DB: query',
  raw: 'direction: right\nClient -> API: request\nAPI -> DB: query',
} satisfies D2BlockNodeProps['node']
</script>

<template>
  <D2BlockNode :node="node" :progressive-interval-ms="500" />
</template>

Props to know:

• progressiveRender, progressiveIntervalMs control incremental re-rendering while streaming.
• themeId, darkThemeId let you pin a D2 theme.
• showHeader, showModeToggle, showCopyButton, showExportButton, showCollapseButton control the toolbar.

4. Dark mode

Pass :is-dark="true" (or add a .dark ancestor via MarkdownRender) to render the diagram in dark mode. markstream-vue prefers the app theme over OS preference to keep previews stable.

5. Custom loaders (optional)

If you disabled the loader earlier, or want to load from a CDN/global build:

import { enableD2, setD2Loader } from 'markstream-vue'

// Re-enable the default loader
enableD2()

// Or supply your own loader
setD2Loader(() => (window as any).D2)

If @terrastruct/d2 is missing, the renderer falls back to showing the source text until it becomes available.