src/outgoingedges.js

/**
 * Yields all edges of an undirected unweighted connected loopless multigraph G
 * that have one endpoint inside some vertex subset U and that have the other
 * endpoint inside of V = V(G) \ U.
 *
 * @param {Map} G The input undirected unweighted connected loopless multigraph.
 * @param {Set} U The subset of edges.
 * @returns {Iterable} The edges of G going from U to V(G) \ U.
 */
export default function* outgoingedges(G, U) {
	for (const u of U) {
		for (const v of G.get(u)) {
			if (!U.has(v)) yield [u, v];
		}
	}
}