UnderFlow

A markdown editor with a live preview and a WYSIWYG mode. It reads and writes CommonMark and GitHub Flavored Markdown, and its WYSIWYG mode is built on ProseMirror.

The editor keeps its focus on content: the markdown it writes is standard CommonMark/GFM that other renderers (remark, GitHub, markdown-it) display the same way, and the preview uses plain element styles so you can apply your own site's stylesheet to it.

Try it here https://liquid-js.github.io/underflow/demo/

Installation

npm install @liquid-js/underflow prosemirror-commands prosemirror-history prosemirror-inputrules \
    prosemirror-keymap prosemirror-model prosemirror-state prosemirror-transform prosemirror-view dompurify
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ProseMirror and DOMPurify are peer dependencies, so your application controls their versions and loads a single copy of each.

Documentation

The guides and the API reference are at https://liquid-js.github.io/underflow/docs/.

Usage

import { Editor } from '@liquid-js/underflow'
import '@liquid-js/underflow/styles/editor.css'

const editor = new Editor({
    el: document.querySelector('#editor')!,
    height: '500px',
    initialEditType: 'markdown',
    previewStyle: 'vertical',
    initialValue: '# Hello'
})

editor.on('change', () => console.log(editor.getMarkdown()))
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To only display markdown, use the viewer, which doesn't load the editing code:

import { Viewer } from '@liquid-js/underflow/viewer'
import '@liquid-js/underflow/styles/viewer.css'

new Viewer({ el: document.querySelector('#viewer')!, initialValue: '# Hello' })
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The JavaScript is minified ES2024, with source maps, that leaves its dependencies to your bundler, and the stylesheets are standard CSS without vendor prefixes: add the prefixes your browser targets need in your application's build, e.g. with Autoprefixer or Lightning CSS.

Entry points

Import	Contents
@liquid-js/underflow	Editor, EditorCore and Viewer
@liquid-js/underflow/viewer	Viewer
@liquid-js/underflow/parser	The incremental markdown parser
@liquid-js/underflow/i18n/<locale>	UI translations, e.g. i18n/de-de
@liquid-js/underflow/plugins/code-syntax-highlight	Syntax highlighting for code blocks
@liquid-js/underflow/styles/editor.css	Editor UI and contents styles
@liquid-js/underflow/styles/editor-only.css	Editor UI without the contents styles, for use with your own
@liquid-js/underflow/styles/viewer.css	Contents styles for the viewer
@liquid-js/underflow/styles/theme/dark.css	Dark theme, enabled with the theme: 'dark' option
@liquid-js/underflow/styles/plugins/code-syntax-highlight.css	Styles of the syntax highlighting plugin
@liquid-js/underflow/scss/<file>.scss	The Sass sources of the stylesheets above, to compile in your own build (see Theming)

Development

yarn install
yarn start      # demo page with the editor and viewer, served from source
yarn build      # library into lib/
yarn test       # unit and integration tests
yarn lint
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See CONTRIBUTING.md for the commit conventions.

License

MIT License