writedown-js

This is an incremental parser for a variant of markdown. writedown-js was created due to the need to generate live previews of arbitrarily sized markdown documents, which became much slower under previous parse-all parsers.

It functions by splitting the document into blocks, and rendering each block individually as required by changes. Metadata changes are also used to trigger block redraws. It uses a modified and optimised Showdown renderer for rendering most blocks, but fast-renders those blocks it knows it is safe to do so (such as headings and code blocks).

Compatibility

Compatible with showdown, with extensions from the mdext showdown fork.

Performance

Rendering the Markdown Syntax page:

Across all test cases (as a multiple of showdown performance):