Floyd_Warshall.js

/*The Floyd Warshall Algorithm is for solving the All Pairs Shortest Path problem.
The problem is to find shortest distances between every pair of vertices in a given
edge weighted directed Graph.This is Floyd Warshall algorithm in java script.*/

class Graph {
    constructor() {
        this.edges = {};
        this.nodes = [];
    }

    addNode(node) {
        this.nodes.push(node);
        this.edges[node] = [];
    }

    addEdge(node1, node2, weight =1) {
        this.edges[node1].push({node:node2, weight:weight });
        this.edges[node2].push({node:node1, weight:weight });
    }

    floydWarshallAlgorithm() {
        let dist = {};
        for (let i = 0; i < this.nodes.length; i++) {
            dist[this.nodes[i]] = {};

            // For existing edges assign the dist to be same as weight
            this.edges[this.nodes[i]].forEach(e = > (dist[this.nodes[i]][e.node] = e.weight));

            this.nodes.forEach(n = > {
                // For all other nodes assign it to infinity
                if (dist[this.nodes[i]][n] == undefined)
                    dist[this.nodes[i]][n] = Infinity;
                    // For self edge assign dist to be 0
                if (this.nodes[i] == = n) dist[this.nodes[i]][n] = 0;
            });
        }

        this.nodes.forEach(i = > {
            this.nodes.forEach(j = > {
                this.nodes.forEach(k = > {
                    // Check if going from i to k then from k to j is better
                    // than directly going from i to j. If yes then update
                    // i to j value to the new value
                    if (dist[i][k] + dist[k][j] < dist[i][j])
                        dist[i][j] = dist[i][k] + dist[k][j];
                });
            });
        });
        return dist;
    }
}

    let g = new Graph();

    var edges = prompt("Please enter number of edges", "5");

    var vertices = prompt("Please enter number of vertices", "5");

    for(let i=0;i<vertices; i++){
        var e=prompt("Please enter vertex name","A");
        g.addNode(e);
    }

    /*g.addNode("A");
    g.addNode("B");
    g.addNode("C");
    g.addNode("D");*/

    for(let i=0;i<edges; i++){
        var e1=prompt("Please enter start edge name","A");
        var e2=prompt("Please enter start edge name","A");
        var w=prompt("Please enter start edge name",100);
        g.addEdge(e1,e2,w);
    }

    /*g.addEdge("A", "C", 100);
    g.addEdge("A", "B", 3);
    g.addEdge("A", "D", 4);
    g.addEdge("D", "C", 3);*/

    console.log(g.floydWarshallAlgorithm());

    /* output : 
    A: {C: 7, B: 3, D: 4, A: 0}
    B: {A: 3, B: 0, C: 10, D: 7}
    C: {A: 7, D: 3, B: 10, C: 0}
    D: {A: 4, C: 3, B: 7, D: 0}*/