turndown-plugin-gfm

turndown-plugin-gfm is a companion plugin for the Turndown HTML-to-Markdown converter that adds the GitHub Flavored Markdown (GFM) rules Turndown’s core doesn’t cover out of the box: strikethrough, tables, and task list items. Each rule is exposed both individually and bundled as a single gfm plugin, so consumers can apply only the extensions they need.

What You Get

• A gfm export that bundles all GFM rules into Turndown with a single turndownService.use(gfm) call
• Individually importable strikethrough, tables, and taskListItems plugins for selective use
• Table conversion that respects column alignment (left/right/center) and only converts tables with a heading row
• Prebuilt CJS, ESM, and browser IIFE bundles alongside the source

Common Use Cases

• Converting GitHub README or wiki HTML back into GFM-flavored Markdown
• Building a markdown-export feature for a rich text or WYSIWYG editor that needs GitHub-style tables and task lists
• Round-tripping HTML content from CMS or scraped pages into Markdown that renders correctly on GitHub

Under The Hood

Architecture: The library is organized as independent Turndown rule modules (strikethrough.js, tables.js, task-list-items.js, highlighted-code-block.js) each exporting a function that calls turndownService.addRule() with a filter and replacement, unified by gfm.js which imports and applies all four via turndownService.use([…]); the tables module additionally maintains its own internal rules object and helper functions (cell, isHeadingRow) to handle GFM table alignment syntax. Tech Stack: Written in plain ES module JavaScript, built with Rollup into CJS/ES/IIFE bundles via config/rollup.config.*.js, tested with a custom turndown-attendant harness and linted with the standard style guide; its only real dependency is the peer Turndown library it plugs into. Code Quality: The test suite (test/turndown-plugin-gfm-test.js) exercises the built bundle rather than source directly and is thin relative to the rule surface (no per-branch alignment/edge-case coverage visible beyond the attendant fixtures); code favors small, single-purpose functions per rule with no classes or heavy abstraction. API Design: The API is minimal and composable, one call to turndownService.use(gfm) or use([tables]) for a-la-carte rule selection, requiring no configuration objects or setup beyond passing rules into an existing TurndownService instance.