How Can I Reference Class Instances That I Have Passed Into A Map As Keys Javascript

I am implementing a graph class using a Map as an adjacency list, with a simple class Vertex that I am using to represent each node in the graph: export class Vertex { construc

Solution 1:

Given your addVertex method creates the Vertex instance and the addEdge method expects that very instance as a parameter, you need to make it available to the caller of these methods - by returning it:

…
addVertex(value) {
    if (value) {
        const vertex = newVertex(value);
        this.adjacencyList.set(vertex, []);
        return vertex;
    }
    // else throw new Error("no value given")?
}
…

Then you can use it like

const graph = newUndirectedGraph();
const vertex1 = graph.addVertex("A");
const vertex2 = graph.addVertex("B");
const vertex3 = graph.addVertex("B");
graph.addEdge(vertex1, vertex2);
graph.addEdge(vertex1, vertex3);
graph.addEdge(vertex2, vertex3);