dfs.js

let graphAdj;
let visited;
let stack;

const initGraph = (maxVertice) => {

    visited = new Array(maxVertice);
    stack = []

    for (let i = 0; i < visited.length; i++) {
        visited[i] = false;
    }

    graphAdj = new Array(maxVertice);
    for (let i = 0; i < graphAdj.length; i++) {
        graphAdj[i] = new Array(maxVertice);
    }

    for (let i = 0; i < graphAdj.length; i++) {
        for (let j = 0; j < graphAdj[i].length; j++) {
            graphAdj[i][j] = 0;
        }
    }

}

const printGraph = () => {
    let graphline = " ";
    let i, j;
    for (i = 0; i < graphAdj.length; i++) {
        for (j = 0; j < graphAdj[i].length; j++) {
            graphline += graphAdj[i][j];
            graphline += " "

            if (j == graphAdj.length - 1) {
                console.log(graphline);
                graphline = ' ';
            }
        }
    }
}


const insertGraph = (a, b) => {
    for (let i = 0; i < graphAdj.length; i++) {
        for (let j = 0; j < graphAdj[i].length; j++) {
            if (i === a && j === b) {
                graphAdj[i][j] = 1;
                graphAdj[j][i] = 1;
            }

        }
    }

}


const dfs = (node) => {

    stack.push(node);

    while (stack.length!=0) {

        node = stack.pop();
       
        if (visited[node] == false) {
            visited[node] = true;

           console.log(`we visited ${node}`)
            for (let j = 0; j < graphAdj[node].length; j++) {
                if (graphAdj[node][j] === 1){
                    stack.push(j);
                }

            }
        }

    }

}


initGraph(4);
insertGraph(0, 1); 
insertGraph(0, 2); 
insertGraph(1, 2); 
insertGraph(2, 0); 
insertGraph(2, 3); 
insertGraph(3, 3); 

printGraph();

dfs(2);