Multi-download progress with AngularJS running in Node Webkit

dprogress.js

angular.module('kalabox.dprogress', [])
  .directive('dprogress', ['_', function (_) {

    var bar_data = [];

    function makeChart() {
      var chart = d3.select('#chart')
        .append("div").attr("class", "chart")
        .selectAll('div')
        .data(bar_data)
        .enter()
        .append("div")
        .transition()
        .style("width", function(d) { return d.progress.percent + "%"; })
        .text(function(d) { return d.progress.percent + "%"; });
    }

    function updateChart() {
      console.log(bar_data);
      var chart = d3.selectAll('#chart');
      bars = chart.selectAll('.chart div')
        .data(bar_data)
        .transition()
        .duration(300)
        .style("width", function(d) { return d.progress.percent + "%"; })
        .text(function(d) { return d.progress.percent + "%"; });
    }

    return {
      restrict: 'E',
      scope: { data: "=ngModel" },
      template: '<div id="chart"></div>',
      link: function (scope, element, attrs) {

        bar_data = scope.data;
        makeChart();

        scope.$watch('data', _.throttle(function(newVal) {
          bar_data = newVal;
          updateChart();
        }, 500), true);
      }
    };
  }]);

install.html

<h1>Kalabox Installer</h1>

<h2>Downloading Components</h2>

<dprogress ng-model="dependencies"></dprogress>

install.js

angular.module('kalabox.install', [])
  .config(function ($routeProvider) {
    $routeProvider.when('/install', {
      templateUrl: 'modules/install/install.html',
      controller: 'InstallCtrl'
    });
  })
  .controller('InstallCtrl', ['$scope', '_', function($scope, _) {
    $scope.dependencies = [
      {
        name: 'Virtual Box',
        filename: 'virtualbox.dmg',
        http_options: {
          host: 'files.kalamuna.com',
          path: '/virtualbox-macosx-4.3.6.dmg'
        },
        progress: {
          downloaded: 0,
          total: 0,
          percent: 0
        }
      },
      {
        name: 'Boot2Docker',
        filename: 'boot2docker.pkg',
        http_options: {
          host: 'files.kalamuna.com',
          path: '/boot2docker-macosx-1.1.1.pkg'
        },
        progress: {
          downloaded: 0,
          total: 0,
          percent: 0
        }
      }
    ];

    var http = require('http');
    var fs = require('fs');
    var mbbytes = 1048576;
    var download_dir = './downloads';

    if (!fs.existsSync(download_dir)) {
      fs.mkdir(download_dir);
    }

    angular.forEach($scope.dependencies, function(dep, key) {
      var filename = dep.http_options.path.split('/').pop();
      var file = fs.createWriteStream(download_dir + '/' + filename);

      http.get(dep.http_options, function(res) {
        var len = parseInt(res.headers['content-length'], 10);
        //var body = "";
        var cur = 0;
        var total = len / mbbytes;

        $scope.dependencies[key].progress.total = total.toFixed(2);

        res.on('data', function(data) {
          cur += data.length;
          file.write(data);

          $scope.$apply(function(){
            $scope.dependencies[key].progress.current = (cur / mbbytes).toFixed(2);
            $scope.dependencies[key].progress.percent = parseInt(100.0 * cur / len);
          });

        });

        res.on('end', function(){
            file.end();
            console.log(filename + ' downloaded to ' + download_dir);
        });
      });
    });

  }]);