footer-leading-blank.ts

import toLines from '@commitlint/to-lines';
import message from '@commitlint/message';
import {SyncRule} from '@commitlint/types';

export const footerLeadingBlank: SyncRule = (parsed, when = 'always') => {
	// Flunk if no footer is found
	if (!parsed.footer) {
		return [true];
	}

	const negated = when === 'never';
	const rawLines = toLines(parsed.raw);
	const footerLines = toLines(parsed.footer);
	const footerOffset = rawLines.indexOf(footerLines[0]);
	const [leading] = rawLines.slice(footerOffset - 1);

	// Check if the first line of footer is empty
	const succeeds = leading === '';

	return [
		negated ? !succeeds : succeeds,
		message([
			'footer',
			negated ? 'may not' : 'must',
			'have leading blank line',
		]),
	];
};