StreamMark

Beautiful terminal markdown renderer with first-class streaming support.

Built for LLM/agent output — renders tokens as they arrive without ever showing broken markdown.

Install

npm install streammark

Peer deps: chalk@^5, string-width@^7

Usage

One-shot render

import { render, print } from 'streammark';

// Get ANSI string back
const ansi = render('# Hello\n\nThis is **streammark**', { theme: 'dracula' });
console.log(ansi);

// Or print directly
print('# Hello\n\nThis is **streammark**', { theme: 'nord' });

Streaming (LLM/agent output)

import { MarkdownStream } from 'streammark';

const md = new MarkdownStream({ theme: 'dark' });

// Anthropic SDK
const stream = await anthropic.messages.stream({ ... });
for await (const chunk of stream) {
  if (chunk.type === 'content_block_delta') {
    md.write(chunk.delta.text);
  }
}
md.end();

// OpenAI SDK
const stream = await openai.chat.completions.create({ stream: true, ... });
for await (const chunk of stream) {
  md.write(chunk.choices[0]?.delta?.content ?? '');
}
md.end();

Themes

| Theme | Description | |-------|-------------| | dark | Default dark, high contrast | | dracula | Dracula palette | | nord | Nord palette | | light | Clean light theme |

// Pass theme name
new MarkdownStream({ theme: 'dracula' });

// Or bring your own theme object
import { themes } from 'streammark';
const myTheme = { ...themes.dark, h1: { color: '#FF0000', bold: true } };
new MarkdownStream({ theme: myTheme });

Streaming Behaviour

| Element | Behaviour | |---------|-----------| | Headings, HR | Rendered immediately when line is complete | | Paragraphs | Rendered line-by-line as newlines arrive | | Code blocks | Buffered until closing ``` — then rendered with syntax highlighting | | Tables | Buffered until table ends — then rendered with borders | | Blockquotes | Buffered until block ends | | Lists | Buffered until paragraph boundary (supports checkboxes) | | Alerts | Buffered and rendered with styled boxes |

GitHub-Style Alerts

Beautiful styled alert boxes for important callouts:

> [!NOTE]
> Useful information that users should know.

> [!TIP]
> Helpful advice for doing things better.

> [!IMPORTANT]
> Key information users need to know.

> [!WARNING]
> Urgent info that needs immediate attention.

> [!CAUTION]
> Advises about risks or negative outcomes.

Alerts support full inline markdown including code, italic, and bold text.

Syntax Highlighting

Supported: js, ts, jsx, tsx, python, bash, sh, json, css, zsh

No external deps — built-in token-based highlighter.

API

render(markdown, opts?) → string

Render a complete markdown string. Returns ANSI-styled string.

print(markdown, opts?)

Render and write to stdout.

new MarkdownStream(opts?)

Streaming renderer.

• opts.theme — theme name or object (default: 'dark')
• opts.output — writable stream (default: process.stdout)

.write(chunk: string)

Feed a chunk (can be a single character/token).

.end()

Flush remaining content and finalize.

.pipe(asyncIterable)

Convenience: pipe any async iterable of string chunks.

Features

• GitHub-style alerts — > [!NOTE], > [!WARNING], > [!TIP], > [!IMPORTANT], > [!CAUTION]
• Streaming-first — Renders tokens as they arrive from LLMs
• 4 beautiful themes — dark, dracula, nord, light
• Syntax highlighting — JavaScript, TypeScript, Python, Bash, JSON, CSS
• Tables & blockquotes — Box-drawing borders and styled quotes
• Checkboxes — Support for - [x] and - [ ] task lists
• Zero dependencies — Built-in tokenizer, no external parsers