@terrible-lexical/markdown/README.md

This package contains Markdown helpers and functionality for Lexical.

# `@terrible-lexical/markdown`

This package contains markdown helpers for Lexical: import, export and shortcuts.

## Import and export
```js
import {
  $convertFromMarkdownString,
  $convertToMarkdownString,
  TRANSFORMERS,
} from '@terrible-lexical/markdown/src';

editor.update(() => {
  const markdown = $convertToMarkdownString(TRANSFORMERS);
  ...
});

editor.update(() => {
  $convertFromMarkdownString(markdown, TRANSFORMERS);
});
```

It can also be used for initializing editor's state from markdown string. Here's an example with react `<RichTextPlugin>`
```jsx
<LexicalComposer initialConfig={{
  editorState: () => $convertFromMarkdownString(markdown, TRANSFORMERS)
}}>
  <RichTextPlugin />
</LexicalComposer>
```

## Shortcuts
Can use `<MarkdownShortcutPlugin>` if using React
```jsx
import { TRANSFORMERS } from '@terrible-lexical/markdown/src';
import {MarkdownShortcutPlugin} from '@terrible-lexical/react/src/LexicalMarkdownShortcutPlugin';

<LexicalComposer>
  <MarkdownShortcutPlugin transformers={TRANSFORMERS} />
</LexicalComposer>
```

Or `registerMarkdownShortcuts` to register it manually:
```js
import {
  registerMarkdownShortcuts,
  TRANSFORMERS,
} from '@terrible-lexical/markdown/src';

const editor = createEditor(...);
registerMarkdownShortcuts(editor, TRANSFORMERS);
```

## Transformers
Markdown functionality relies on transformers configuration. It's an array of objects that define how certain text or nodes
are processed during import, export or while typing. `@terrible-lexical/markdown` package provides set of built-in transformers:
```js
// Element transformers
UNORDERED_LIST
CODE
HEADING
ORDERED_LIST
QUOTE

// Text format transformers
BOLD_ITALIC_STAR
BOLD_ITALIC_UNDERSCORE
BOLD_STAR
BOLD_UNDERSCORE
INLINE_CODE
ITALIC_STAR
ITALIC_UNDERSCORE
STRIKETHROUGH

// Text match transformers
LINK
```

And bundles of commonly used transformers:
- `TRANSFORMERS` - all built-in transformers
- `ELEMENT_TRANSFORMERS` - all built-in element transformers
- `TEXT_FORMAT_TRANSFORMERS` - all built-in text format transformers
- `TEXT_MATCH_TRANSFORMERS` - all built-in text match transformers

Transformers are explicitly passed to markdown API allowing application-specific subset of markdown or custom transformers.

There're three types of transformers:

- **Element transformer** handles top level elements (lists, headings, quotes, tables or code blocks)
- **Text format transformer** applies text range formats defined in `TextFormatType` (bold, italic, underline, strikethrough, code, subscript and superscript)
- **Text match transformer** relies on matching leaf text node content

See `MarkdownTransformers.js` for transformer implementation examples