Tarjan's strongly connected components algorithm in Javascript - followed pseudocode from http://en.wikipedia.org/wiki/Tarjan%E2%80%99s_strongly_connected_components_algorithm

gistfile1.js

window.onload = function() {

    var v0 = new Vertex("0");
    var v1 = new Vertex("1");
    var v2 = new Vertex("2");
    var v3 = new Vertex("3");
    var v4 = new Vertex("4");
    var v5 = new Vertex("5");
    var v6 = new Vertex("6");
    var v7 = new Vertex("7");
    var v8 = new Vertex("8");
    var v9 = new Vertex("9");
    var v10 = new Vertex("10");
    var v11 = new Vertex("11");
    var v12 = new Vertex("12");

    v0.connections.push(v1);
    v0.connections.push(v5);
    v2.connections.push(v0);
    v2.connections.push(v3);
    v3.connections.push(v2);
    v3.connections.push(v5);
    v4.connections.push(v2);
    v4.connections.push(v2);
    v5.connections.push(v4);
    v6.connections.push(v0);
    v6.connections.push(v9);
    v7.connections.push(v6);
    v7.connections.push(v8);
    v8.connections.push(v7);
    v8.connections.push(v9);
    v9.connections.push(v10);
    v9.connections.push(v11);
    v10.connections.push(v12);
    v11.connections.push(v4);
    v11.connections.push(v12);
    v12.connections.push(v9);

    var vertices = [v0,v1,v2,v3,v4,v5,v6,v7,v8,v9,v10,v11,v12];
    
    var graph = new Graph(vertices);
    var tarjan = new Tarjan(graph);
    
    var scc = tarjan.run();
    console.log(scc);
    
};

function Graph(vertices){
    this.vertices = vertices || [];
}

function Vertex(name){
    this.name = name || null;
    this.connections = [];
    
    // used in tarjan algorithm
    // went ahead and explicity initalized them
    this.index= -1;
    this.lowlink = -1;
}
Vertex.prototype = {
    equals: function(vertex){
        // equality check based on vertex name
        return (vertex.name && this.name==vertex.name);
    }
};

function VertexStack(vertices) {
    this.vertices = vertices || [];
}
VertexStack.prototype = {
    contains: function(vertex){
        for (var i in this.vertices){
            if (this.vertices[i].equals(vertex)){
                return true;
            }
        }
        return false;
    }
};

function Tarjan(graph) {
    this.index = 0;
    this.stack = new VertexStack();
    this.graph = graph;
    this.scc = [];
}
Tarjan.prototype = {
    run: function(){
        for (var i in this.graph.vertices){
            if (this.graph.vertices[i].index<0){
                this.strongconnect(this.graph.vertices[i]);
            }
        }
        return this.scc;
    },
    strongconnect: function(vertex){
        // Set the depth index for v to the smallest unused index
        vertex.index = this.index;
        vertex.lowlink = this.index;
        this.index = this.index + 1;
        this.stack.vertices.push(vertex);
        
        // Consider successors of v
        // aka... consider each vertex in vertex.connections
        for (var i in vertex.connections){
            var v = vertex;
            var w = vertex.connections[i];
            if (w.index<0){
                // Successor w has not yet been visited; recurse on it
                this.strongconnect(w);
                v.lowlink = Math.min(v.lowlink,w.lowlink);
            } else if (this.stack.contains(w)){
                // Successor w is in stack S and hence in the current SCC
                v.lowlink = Math.min(v.lowlink,w.index);
            }
        }
        
        // If v is a root node, pop the stack and generate an SCC
        if (vertex.lowlink==vertex.index){
            // start a new strongly connected component
            var vertices = [];
            var w = null;
            if (this.stack.vertices.length>0){
                do {
                    w = this.stack.vertices.pop();
                    // add w to current strongly connected component
                    vertices.push(w);
                } while (!vertex.equals(w));
            }
            // output the current strongly connected component
            // ... i'm going to push the results to a member scc array variable
            if (vertices.length>0){
                this.scc.push(vertices);
            }
        }
    }
};

@sgress454 can you give code for circling.

Thank you so much, saved me a lot of time!

@marius7383 welcome :)

Not sure if this is useful for anyone here, but I did a quick conversion of this gist to TypeScript: https://gist.github.com/lencioni/835beff2b231b6ef7d1c070adb5e583e