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

Syntax Highlighting

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

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.