panphora/overtype
Overtype
Overtype is a web-based markdown editor that provides a WYSIWYG editing experience. It allows users to manage markdown content through a real-time visual preview while maintaining the simplicity of native text input. The project focuses on secure markdown rendering by sanitizing input and neutralizing dangerous links to prevent XSS attacks.
The editor is implemented as a native web component using Shadow DOM encapsulation, ensuring style isolation and framework-agnostic integration. It uses a transparent overlay rendering technique to simulate a visual editor while preserving native input behavior. The system is extensible via a plugin-based parsing architecture that allows for custom syntax patterns and post-processing logic.
The project covers a broad range of capabilities including rich text formatting workflows with customizable toolbars, real-time syntax highlighting for code blocks, and automated list continuation. It includes tools for document statistics tracking, file upload handling via drag-and-drop, and the ability to toggle between editing, raw text, and read-only modes.
Initialization can be handled declaratively through HTML data attributes, and the editor supports native HTML form integration for validation.
Features
- WYSIWYG Mode - Provides a WYSIWYG editing mode where markdown is rendered in real-time via a transparent overlay.
- WYSIWYG Rendering Engines - Implements a real-time markdown rendering engine using a transparent overlay to maintain precise cursor positioning.
- Markdown Editors - Provides a full web-based editor for authoring and formatting Markdown documents with integrated file and statistics management.
- Markdown Parsing Pipelines - Provides a plugin-based markdown parsing pipeline for injecting custom syntax patterns and post-processing logic.
- Secure Markdown Rendering - Implements a secure markdown rendering pipeline that sanitizes input and neutralizes dangerous links to prevent XSS attacks.
- Markdown to HTML Renderers - Includes a utility to convert markdown text into HTML strings without DOM dependencies for server-side rendering.
- URL Protocol Sanitizers - Prevents XSS attacks by blocking dangerous URL protocols and neutralizing malicious links in rendered content.
- Input-Transparent Overlays - Simulates a WYSIWYG experience by positioning a transparent textarea overlay over a styled HTML preview.
- Shadow DOM Encapsulation - Uses Shadow DOM encapsulation to isolate styles and ensure the editor is framework-agnostic.
- Shadow-DOM Editor Components - Implemented as a native web component using Shadow DOM encapsulation to ensure style isolation and framework-agnosticism.
- Editor Content APIs - Provides a JavaScript API and declarative attributes to programmatically set and retrieve markdown text and rendered HTML.
- Editor Appearance Customizations - Provides reactive attributes for customizing the editor's visual theme, dimensions, typography, and padding.
- Editor Feature Toggles - Includes runtime controls to toggle functional features like formatting toolbars, document statistics, and read-only mode.
- Editing View Modes - Allows toggling between WYSIWYG editing, raw plain-text markdown, and read-only preview modes.
- Editor Toolbar Configurations - Ships a customizable formatting toolbar with SVG icons and callbacks that respond to the cursor position.
- Custom Color Theme Definitions - Maps configuration objects to CSS custom properties for dynamic global or per-instance visual theming.
- Declarative Instance Initializers - Allows multiple editor instances to be initialized declaratively using HTML data attributes and form properties.
- Syntax-Highlighted Code Blocks - Provides real-time syntax highlighting for code blocks through integration with external highlighter libraries.
- Rich Text Input Workflows - Facilitates the application of bold, italic, and list formatting via customizable toolbars and keyboard shortcuts.
- CSS Custom Property Injections - Implements a theming system that injects CSS custom properties derived from configuration objects to update the editor's appearance.
- Configuration Attributes - Initializes editor settings and state by parsing JSON-encoded HTML data attributes during the component lifecycle.
- Markdown Parser Extensions - Offers a plugin-based architecture to extend markdown parsing with custom syntax patterns and post-processing logic.
