ANSI Theme

The theme option in toAnsi() lets you override individual style entries. Only the keys you provide are replaced; everything else falls back to the built-in defaults.

AnsiStyle Shape

interface AnsiStyle {
  open: string   // ANSI escape sequence to start the style
  close: string  // ANSI escape sequence to end the style
}

AnsiTheme Key Reference

Key	Type	Default effect
h1	AnsiStyle	Bold + underline (\x1b[1;4m / \x1b[0m)
h2	AnsiStyle	Bold (\x1b[1m / \x1b[0m)
h3	AnsiStyle	Bold (\x1b[1m / \x1b[0m)
bold	AnsiStyle	Bold (\x1b[1m / \x1b[22m)
italic	AnsiStyle	Italic (\x1b[3m / \x1b[23m)
strikethrough	AnsiStyle	Strikethrough (\x1b[9m / \x1b[29m)
inlineCode	AnsiStyle	Reverse video (\x1b[7m / \x1b[27m)
codeBlock	AnsiStyle	Box-drawing border
blockquote	AnsiStyle	Dim (\x1b[2m / \x1b[22m) + │ prefix
link	AnsiStyle	Underline (\x1b[4m / \x1b[24m)
listBullet	string	•
hrChar	string	─

Monochrome Theme Example

Bold only, no colour — useful for accessibility or non-colour terminals:

import { toAnsi } from 'md-to-rich'
import type { AnsiTheme } from 'md-to-rich'

const monochromeTheme: Partial<AnsiTheme> = {
  h1: { open: '\x1b[1m', close: '\x1b[0m' },
  h2: { open: '\x1b[1m', close: '\x1b[0m' },
  h3: { open: '\x1b[1m', close: '\x1b[0m' },
  inlineCode: { open: '\x1b[7m', close: '\x1b[27m' },   // reverse video
  codeBlock: { open: '', close: '' },
  blockquote: { open: '\x1b[2m', close: '\x1b[22m' },   // dim
  link: { open: '\x1b[4m', close: '\x1b[24m' },         // underline only
  hrChar: '─',
  listBullet: '-',
}

const output = toAnsi(md, { columns: 80, theme: monochromeTheme })

Fun Theme Example

Custom bullet points and HR character:

const funTheme: Partial<AnsiTheme> = {
  listBullet: '→',
  hrChar: '·',
}

toAnsi('- Alpha\n- Beta\n- Gamma\n\n---', { columns: 40, theme: funTheme })
// → List items prefixed with →
// → HR rendered as ·····...

Colour Codes Reference

Common ANSI escape sequences for building themes:

Effect	Open	Close
Bold	\x1b[1m	\x1b[22m
Dim	\x1b[2m	\x1b[22m
Italic	\x1b[3m	\x1b[23m
Underline	\x1b[4m	\x1b[24m
Reverse	\x1b[7m	\x1b[27m
Strikethrough	\x1b[9m	\x1b[29m
Red fg	\x1b[31m	\x1b[39m
Green fg	\x1b[32m	\x1b[39m
Blue fg	\x1b[34m	\x1b[39m
Cyan fg	\x1b[36m	\x1b[39m
Reset all	\x1b[0m	—