Graphs

[zhorton34]

class Edge {
  constructor(start, end, weight = null) {
    this.start = start;
    this.end = end;
    this.weight = weight;
  }
}

class Vertex {
  constructor(data) {
    this.data = data;
    this.edges = [];
  }

  addEdge(vertex, weight) {
    if (vertex instanceof Vertex) {
      this.edges.push(new Edge(this, vertex, weight));
    } else {
      throw new Error('Edge start and end must both be Vertex');
    }
  }

  removeEdge(vertex) {
    this.edges = this.edges.filter(edge => edge.end !== vertex);
  }

  print() {
    const edgeList = this.edges.map(edge =>
        edge.weight !== undefined ? `${edge.end.data} (${edge.weight})` : edge.end.data) || [];

    const output = `${this.data} --> ${edgeList.join(', ')}`;
    console.log(output);
  }
}

class Graph {
  constructor(isWeighted = false, isDirected = false) {
    this.vertices = [];
    this.isWeighted = isWeighted;
    this.isDirected = isDirected;
  }

  addVertex(data) {
    const newVertex = new Vertex(data);
    this.vertices.push(newVertex);

    return newVertex;
  }

  removeVertex(vertex) {
    this.vertices = this.vertices.filter(v => v !== vertex);
  }

  addEdge(vertexOne, vertexTwo, weight) {
    const edgeWeight = this.isWeighted ? weight : null;

    if (vertexOne instanceof Vertex && vertexTwo instanceof Vertex) {
      if (this.isDirected === false) {
        vertexOne.addEdge(vertexTwo, edgeWeight);
      
        vertexTwo.addEdge(vertexOne, edgeWeight);
      } else {
        vertexOne.addEdge(vertexTwo, edgeWeight);
      }
    } else {
      throw new Error('Expected Vertex arguments.');
    }
  }

  removeEdge(vertexOne, vertexTwo) {
    if (vertexOne instanceof Vertex && vertexTwo instanceof Vertex) {
      if (this.isDirected === false) {
        vertexOne.removeEdge(vertexTwo);
      
        vertexTwo.removeEdge(vertexOne);
      } else {
        vertexOne.removeEdge(vertexTwo);
      }

    } else {
      throw new Error('Expected Vertex arguments.');
    }
  }

  print() {
    this.vertices.forEach(vertex => vertex.print());
  }
}