Function parseMarkdownFile

parseMarkdownFile(filename: string): Promise<ParseResult>
Parses a markdown file with YAML frontmatter.

Extracts frontmatter delimited by --- markers at the beginning of the file and parses it as YAML. The remaining content is returned as plain text. Returns a Result type with either success (parsed data) or failure (error details).

This function converts string dates in the format 'yyyy-dd-dd' to Date data types.
Parameters
- filename: string
  Absolute or relative path to the markdown file
Returns Promise<ParseResult>
Promise resolving to ParseResult with success/failure information
Example
Parse a markdown file
```
const result = await parseMarkdownFile('./posts/article.md');

if (result.success) {
  console.log('Title:', result.data.frontMatter.title);
  console.log('Content length:', result.data.content.length);
} else {
  console.error(`Parse failed: ${result.filename}`);
  console.error(`Error: ${result.error}`);
}
```
Example
Handle parsing errors
```
const result = await parseMarkdownFile('invalid.md');
if (!result.success) {
  console.error(`Failed to parse ${result.filename}: ${result.error}`);
}
```
- Defined in markdown.ts:230