_working-but-complicated.md

Working but complicated

In this example we'd like to have a factory that works per request and allows to keep track of created Models We create a factory per request and pass it around to the parts of the code that need access This can quickly lead to hard to understand, messy code

app.js

var express = require('express'),
    app = express(),
    factory = require('./factory'),
    View = require('./view');

app.all('*', function(req, res, next) {
    // We create a factory for every request and pass it to the view
    // This quickly becomes hard to manage if you need it in multiple parts of the code,
    // It would be much better if every part of the application that needs access
    // could simply import the singleton using the standard `require` or get it from some kind
    // of global scope that is created per request and doesn't get polluted when things are done async
    
    var perRequestFactory = factory();
    var view = new View({
        factory: perRequestFactory,
        collapsed: req.cookie.viewState.collapsed,
        hidden: req.cookie.viewState.hidden
    });

    var responseTime = Math.random() * 2500; // random response time
    // Simulate async tasks
    setTimeout(function () {
        res.send(perRequestFactory.serializeModels());
    }, responseTime);

});

app.listen(8000);

factory.js

// Basically a factory for factories
// For every request we create a new one

var Model = require('backbone').Model;

module.exports = function createFactory () {
    var allModels = [];

    return {
        createModel: function (data) {
            var model = new Model(data);
            allModels.push(model);
            return model;
        },
        serializeModels: function () {
            return allModels.map(function (model) {
                return model.toJSON();
            });
        },
        reset: function () {
            allModels = [];
        }
    }
};

view.js

var View = require('backbone').View;

module.exports = View.extend({
    initialize: function (options) {
        this.viewState = options.factory.createModel({
            collapsed: options.collapsed,
            hidden: options.hidden
        });
    }
});