BFS.js

'use strict'

var fs = require('fs');

/**
 * Breadth-first search
 * @param m {Array}
 * @param s {Number}
 */
function BFS(m, s) {
    let visited = new Array(m.length).fill(false),
        q = [];

    q.push(s || 0);
    while(q.length) {
        const t = q.pop();
        visited[t] = true;

        for (let i = 0; i < m.length; ++i) {
            if(m[t][i] == 1) {
                q.unshift(i);
            }
        }
    }

    let i = 0;
    for(; i < m.length && visited[i]; ++i);

    return i === m.length ? true : false;
}

fs.readFile('graph.txt', 'utf-8', function (err, data) {
    if (err) {
        throw new Error(err);
    }

    data = data.split('\n');

    let matrix = [];
    for (let i in data) {
        if (data[i] != '') {
            matrix.push(data[i].split(' '));
        }
    }

    for (let i in matrix) {
        for (let j in matrix[i]) {
            matrix[i][j] = Number(matrix[i][j]);
        }
    }

    console.log(BFS(matrix));
});