lexical_markdown

Markdown import and export for lexical_core. Pure Dart.

dependencies:
  lexical_markdown: ^1.0.0

editor.update(() {
  $convertFromMarkdown(source, transformers: defaultMarkdownTransformers);
}, discrete: true);

final back = editor.read(
  () => $convertToMarkdown(transformers: defaultMarkdownTransformers),
);

One declaration, both directions

Conversion is built from transformers: each describes one construct going in and coming out.

final ElementTransformer headingTransformer = ElementTransformer(
  regExp: RegExp(r'^(#{1,6})\s+(.*)$'),
  replace: (block, children, match) => block.replace(
    $createHeadingNode(HeadingTag.values[match.group(1)!.length - 1])
      ..appendAll(children),
  ),
  export: (node, exportChildren) => node is! HeadingNode
      ? null
      : '${'#' * node.tag.level} ${exportChildren(node)}',
);

Splitting import and export into separate tables makes it easy to write a heading that reads ## but writes something else, and hard to notice. Keeping them in one place makes that particular bug unwriteable.

What survives, and what does not

Markdown is lossier than the document model, and this package is honest about it rather than pretending otherwise.

Round-trips: headings, quotes, paragraphs, bullet, ordered and check lists including nesting, fenced code with its language, links with titles, and bold / italic / strikethrough / inline code.

Does not: block alignment, indentation, text colour and other CSS, marks, hashtags, mentions, tables. None of these have a markdown spelling.

Use the JSON wire format to move documents between editors. Use markdown to move them between people.

Licence

MIT. Portions derived from Lexical, © Meta Platforms, Inc. See the repository.