Алгоритм Прима

1function prim(edges: Edge[], start: string): Edge[] {
2  const inTree = new Set<string>([start])
3  const mst: Edge[] = []
4 
5  while (inTree.size < vertices(edges).length) {
6    // самое дешёвое ребро из дерева наружу
7    let best: Edge | null = null
8    for (const e of edges) {
9      const out = inTree.has(e.from) !== inTree.has(e.to)
10      if (out && (best === null || e.weight < best.weight)) best = e
11    }
12    inTree.add(best!.from)
13    inTree.add(best!.to)
14    mst.push(best!)
15  }
16 
17  return mst
18}