Traverse option to automatically add siblings

[ignatiusmb]

Ability to pass in a siblings option that could format the sibling object. Will definitely need to receive a callback that returns the formatted item, and maybe another callback to check the breakpoint. Putting in the code from mauss.dev as reference.

function fillSiblings<T extends Child>(
	articles: T[],
	base: string,
	breakpoint?: (next: T) => boolean
): T[] {
	for (let i = 0; i < articles.length; i++) {
		if (!articles[i]['siblings']) articles[i]['siblings'] = {};
		const [prev, next] = [articles[i - 1], articles[i + 1]];
		if (prev) articles[i]['siblings']['prev'] = { slug: base + prev.slug, title: prev.title };
		if (breakpoint && breakpoint(next)) return articles;
		if (next) articles[i]['siblings']['next'] = { slug: base + next.slug, title: next.title };
	}
	return articles;
}

The default value will definitely be undefined as it will not generate siblings by default. Passed options however, might either receive an object or just a single callback function. More inclined to the first one as the latter seems overcomplicated and inconvenient.

siblings: {
  item: ({ prev, next }) => any,
  breakpoint: (next: T) => boolean
}