Method addVertex

src/data-structures/graph/Graph.js:15–25

* @param {GraphVertex} newVertex * @returns {Graph}

(newVertex)

   * @returns {Graph}
   */
  addVertex(newVertex) {
    const key = newVertex.getKey();

    if (this.vertices[key]) {
      throw new Error('Vertex has already been added before');
    }

    this.vertices[key] = newVertex;

    return this;
  }

  /**
   * @param {string} vertexKey