mermaid-rs-renderer-js

Native Node.js bindings for mermaid-rs-renderer. It renders Mermaid diagrams directly in Rust without Chromium, Puppeteer, or a browser runtime.

Install

pnpm add mermaid-rs-renderer-js

Render

render runs on Node.js's worker pool. Use renderSync only when blocking the event loop is acceptable.

import { render, Theme } from 'mermaid-rs-renderer-js'

const svg = await render('flowchart LR; A-->B-->C', {
  theme: Theme.Dark,
  nodeSpacing: 60,
  rankSpacing: 80,
  preferredAspectRatio: 16 / 9,
})

CommonJS is supported too:

const { renderSync } = require('mermaid-rs-renderer-js')

const svg = renderSync('sequenceDiagram\nAlice->>Bob: Hello')

API

render(source: string, options?: RenderOptions): Promise<string>
renderSync(source: string, options?: RenderOptions): string

measure(source: string, options?: RenderOptions): Promise<SvgDimensions>
measureSync(source: string, options?: RenderOptions): SvgDimensions

validate(source: string): Promise<void>
validateSync(source: string): void

renderWithTiming(source: string, options?: RenderOptions): Promise<RenderTiming>
renderWithTimingSync(source: string, options?: RenderOptions): RenderTiming

Built-in themes are modern, default, dark, forest, and neutral. A Mermaid %%{init: ...}%% directive can override theme variables and layout configuration for one diagram.

The supported Mermaid syntax and current rendering limitations follow the upstream renderer.

Development

pnpm install
pnpm build:debug
pnpm test
pnpm test:rust
pnpm check

License

MIT