To add a vertex, we can simply add a key to the hash table. The same with removal -- we'll just remove the key. However, with removal, there is the caveat that we also need to ensure that the node to be removed is also disregarded as a neighbor of other nodes.
In other words, if node A is a neighbor of B, and node A is to be removed, we should update B's adjacency list.
xxxxxxxxxx18
addVertex(nodeVal) { this.adjacencyList.set(nodeVal, []); // set a key with the node value, // and an array to contain neighbors }​removeVertex(val) { if (this.adjacencyList.get(val)) { this.adjacencyList.delete(val); }​ this.adjacencyList.forEach((vertex) => { const neighborIdx = vertex.indexOf(val); if (neighborIdx >= 0) { vertex.splice(neighborIdx, 1); } })}OUTPUT
:001 > Cmd/Ctrl-Enter to run, Cmd/Ctrl-/ to comment