import TurndownService from 'turndown';
/**
* Configures a Turndown service with custom rules for code blocks, tables, etc.
* @returns A configured TurndownService instance
*/
export function configureTurndownService(): TurndownService {
const turndownService = new TurndownService({
codeBlockStyle: 'fenced',
headingStyle: 'atx'
});
// Code blocks rule
turndownService.addRule('codeBlocks', {
filter: function (node) {
return node.nodeName === 'PRE';
},
replacement: function (content, node) {
// Cast node to HTMLElement to access getAttribute
const htmlNode = node as HTMLElement;
const code = htmlNode.querySelector('code');
const language = code?.className?.match(/language-(\w+)/)?.[1] ||
htmlNode.getAttribute('data-language') ||
'yaml';
const cleanContent = content
.replace(/^\n+|\n+$/g, '')
.replace(/\n\n+/g, '\n');
return `\n\`\`\`${language}\n${cleanContent}\n\`\`\`\n`;
}
});
// Table cell rule
turndownService.addRule('tableCell', {
filter: ['th', 'td'],
replacement: function (content, node) {
const htmlNode = node as HTMLElement;
// Extract text from nested paragraph if present
let cellContent = '';
if (htmlNode.querySelector('p')) {
cellContent = Array.from(htmlNode.querySelectorAll('p'))
.map(p => p.textContent || '')
.join(' ')
.trim();
} else {
cellContent = content.trim();
}
return ` ${cellContent.replace(/\|/g, '\\|')} |`;
}
});
// Table row rule
turndownService.addRule('tableRow', {
filter: 'tr',
replacement: function (content, node) {
const htmlNode = node as HTMLTableRowElement;
const cells = Array.from(htmlNode.cells);
const isHeader = htmlNode.parentNode?.nodeName === 'THEAD';
let output = '|' + content.trimEnd();
// If this is a header row, add the separator row without extra newline
if (isHeader) {
const separator = cells.map(() => '---').join(' | ');
output += '\n|' + separator + '|';
}
// Only add newline if not a header row or if there's no next row
if (!isHeader || !htmlNode.nextElementSibling) {
output += '\n';
}
return output;
}
});
// Table rule
turndownService.addRule('table', {
filter: 'table',
replacement: function (content) {
// Clean up any potential double newlines
return '\n' + content.replace(/\n+/g, '\n').trim() + '\n';
}
});
// Custom rule to preserve whitespace in table cells
turndownService.addRule('preserveTableWhitespace', {
filter: function (node) {
return (
(node.nodeName === 'TD' || node.nodeName === 'TH') &&
node.textContent?.trim().length === 0
);
},
replacement: function () {
return ' |';
}
});
return turndownService;
}
