astro/dist/core/head-propagation/graph.js

Astro is a modern site builder with web best practices, performance, and DX front-of-mind.

/**
* Computes all importer ancestors that should be treated as `in-tree`.
*
* @example
* If `Button.astro` is imported by `PostLayout.astro`, which is imported by
* `src/pages/blog.astro`, then seeding with `Button.astro` marks all three.
*/
export function computeInTreeAncestors(input) {
	const inTree = new Set();
	const seen = new Set();
	function walk(moduleId) {
		if (seen.has(moduleId)) return;
		seen.add(moduleId);
		// Stop traversal at propagation boundaries.
		if (input.stopAt?.(moduleId)) {
			return;
		}
		inTree.add(moduleId);
		for (const importer of input.importerGraph.get(moduleId) ?? []) {
			walk(importer);
		}
	}
	for (const seed of input.seeds) {
		walk(seed);
	}
	return inTree;
}
export function buildImporterGraphFromModuleInfo(moduleIds, getModuleInfo) {
	// Normalize host graph APIs into a single adjacency map.
	const graph = new Map();
	for (const id of moduleIds) {
		const mod = getModuleInfo(id);
		if (!mod) continue;
		graph.set(id, new Set([...mod.importers, ...mod.dynamicImporters]));
	}
	return graph;
}