Read in an HTML file, look for images, and download with Node.js

download.js

var cheerio = require('cheerio');
var fs = require('fs');
var concat = require('concat-stream');
var _ = require('lodash');
var request = require('request');

var stream = fs.createReadStream([__dirname, '/raw.html'].join(''));
var imagesDir = [__dirname, '/images'].join('');

stream.pipe(concat(function(body) {
    processData(body.toString());
}));

fs.exists(imagesDir, function(exists) {
    if (exists) return true;

    fs.mkdir(imagesDir, 0777, function(err) {
       if (err) throw new Error(err);
    });
});

function download(url, i) {
    var filename, filepath, file;
    filename = url.split('/');
    filename = filename[filename.length - 1];

    filepath = [__dirname, '/images/', filename].join('');

    function callback() {
        console.log(filename, 'done');
    }

    file = fs.createWriteStream(filepath);
    request(url).pipe(file).on('close', callback);
}

function processData(data) {
    var $ = cheerio.load(data);
    var $images = $('div');
    var urls = [];

    $images.each(function() {
        urls.push($(this).attr('data-href'));
    });

    _.each(urls, download);
}