Tag: javascript

AngularJS: Use jQuery to serialize a form

By Ashish Datta | Leave a Comment on AngularJS: Use jQuery to serialize a form

Note: This is a bad idea™. Don’t do it unless you know why you’re doing it.

AngularJS’s form control to Javascript object binding is pretty core to how the framework works but at some point you might find yourself wishing you could just serialize a form. Maybe you’re getting the HTML for the form from a 3rd party source so it would be hard to bind to an object. Or maybe the form you have is huge and you don’t really care about validating it. So how can you serialize a form in AngularJS like you would in jQuery?

What you need to do is create a custom directive to render you form, use the directive’s “link” function to grab the form element, and then use jQuery’s serialize() function to generate a string that you could shoot off in a POST request.

Here’s a sample implementation:


Again, you should really only do this if you have a valid reason since you’re really fighting the framework by manipulating data this way.

React Native: Loading onto iOS devices

By Phil Booth | Leave a Comment on React Native: Loading onto iOS devices

After testing our React Native app on the simulator for a day or two we, similar to a young Kobe Bryant, decided to forgo college and take our talents to the big leagues, by testing our native app on an actual device.

This is a good practice because from a hardware standpoint you’re phone is a very different device than your Mac. Because of the more powerful CPU in your computer there is always the chance that applications that run seamlessly on the Computer’s simulator run choppy on an actual device.

For our purposes we wanted to ensure that our react Native components looked and felt native on a device, and that the positive results produced on the simulator were not just a fluke.

The Nitty Gritty

In our experience the process of getting an App on an actual device is somewhat painful. To help you avoid the same pitfalls that caused us headaches we wanted to give you some solutions to the most common problems you will run into while trying to get your app on your device.

  1. Setting up your iOS developer account: First and foremost it is import to correctly configure your iOS developer account so that you can run your application on an iOS device. This step is easily the most painful part of the process because of how much outdated information that exists on this subject. After poking around for a bit this was the most helpful tutorial that we could find – How to Deploy your App on an iPhone
  2. Plugin your device and ensure that your Xcode and iOS versions are compatible: Right after your developer account is setup the next step is to check and make sure that you are running compatible versions of Xcode and iOS. If not then you will be given an error saying, “The Developer Disk Image could not be mounted”. The simplest fix for this issue is to always make sure that you are running the most recent versions of Xcode and iOS. However, if for some reason you do not want to update your version of Xcode another fix would be to set the deployment target of your application to a version equal to or behind the current version of iOS running on your phone.

  3. Accessing the development server from the device: Now that your app is installed on your device feel free to open it up and navigate through it’s screen. However, if the app needs to make calls to a server running locally on your computer then you are going to have to connect your app to that server. The fastest way to do this is to update the AppDelegate.m file and change the IP in the URL form localhost to your laptop’s IP address. For more information on this step checkout the react documentation at – Running On Device – React Native

NodeJS: Running code in parallel with child_process

By Ashish Datta | Leave a Comment on NodeJS: Running code in parallel with child_process

One of the nice things about nodejs is that since the majority of its libraries are asynchronous it boasts strong support for concurrently performing IO heavy workloads. Even though node is single threaded the event loop is able to concurrently progress separate operations because of the asynchronous style of its libraries. A canonical example would something like fetching 10 web pages and extracting all the links from the fetched HTML. This fits into node’s computational model nicely since the most time consuming part of an HTTP request is waiting around for the network during which node can use the CPU for something else. For the sake of discussion, let’s consider this sample implementation:

Request debugging is enabled so you’ll see that node starts fetching all the URLs at the same time and then the various events fire at different times for each URL:

So we’ve demonstrated that node will concurrently “do” several things at the same time but what happens if computationally intensive code is tying up the event loop? As a concrete example, imagine doing something like compressing the results of the HTTP request. For our purposes we’ll just throw in a while(1) so it’s easier to see what’s going on:

If you run the script you’ll notice it takes much longer to finish since we’ve now introduced a while() loop that causes each URL to take at least 5 seconds to be processed:

And now back to the original problem, how can we fetch the URLs in parallel so that our script completes in around 5 seconds? It turns out it’s possible to do this with node with the child_process module. Child_process basically lets you fire up a second nodejs instance and use IPC to pass messages between the parent and it’s child. We’ll need to move a couple of things around to get this to work and the implementation ends up looking like:

What’s happening now is that we’re launching a child process for each URL we want to process, passing a message with the target URL, and then passing the links back to the parent. And then running along with a timer results in:

It isn’t exactly 5 seconds since there’s a non-trivial amount of time required to start each of the child processes but it’s around what you’d expect. So there you have it, we’ve successfully demonstrated how you can achieve parallelism with nodejs.

React Native: 48 hrs with React

By Phil Booth | Leave a Comment on React Native: 48 hrs with React

Here at Setfive, when not helping our clients with their technology woes, we love experimenting with fun new technology and continuously growing our professional tool kit. As of late we have been throwing around some potential ideas for a Setfive iPhone app (get Chicken Pad Thai delivered no matter where you are in the world) and have been looking at a couple of tools to turn this lofty dream into a reality.

Since no one in the office has any significant experience with Objective C or Swift we decided that, rather than bang our heads against the wall trying to learn the nuances of yet another programming language, we would look to one that we already know, and decided to dip our toes into the JavaScript driven React Native ecosystem.

In the past we have taken our chances with other cross-platform native apps (PhoneGap in particular) that allow you to wrap a web app into a web view however, these methods fall short; if the looks of your app don’t bother you then the serious performance hit that comes from interfacing directly with native objects will.

If you are unfamiliar with React Native, it’s an open source JavaScript framework, built by Facebook, that allows the production of iOS and Android applications using a syntax familiar to HTML. What separates React from other frameworks is that it runs a separate JavaScript thread to control the UI of your application so it can utilize native mobile components. The idea is that this should lead to a seamless user experience that feels both polished and native. After some hands on experience we can say that React did not disappoint.

What we built

In order to test React a little bit farther than the simple hello world example we decided to build a simple application on top of our preexisting Rotorobot API. This app allows users to see the available players for a daily fantasy sports contest on that night.

To get started, we needed an index page that would show up when the app was loaded. Just to keep things simple we incorporated a minimalist layout with a UIButton that responds when pressed.

Upon pressing the button a new scene is added to the storyboard of our application. This scene is a ListView Component that has a row for every available slate of games that will be played that night. In addition, each one of these rows is also wrapped in a TouchableHighlight Component, which allows them to respond to touches.

Any row that you touch results in an AJAX request being made to the Rotorobot API and the available players in that slate are displayed, sorted in descending order based on salary.

Our Experience

Getting something up and running with React Native was definitely a lot easier than expected. It was honestly as simple as using npm to install react-native-cli and then creating a new react native project using react-native init. The init function provides everything that you need to run a React Native application.

After your project has been setup it’s time for all of you Xcode naysayers to either bite the bullet and download Xcode or look for guidance in the form of another SaaS solution.

In order to help you out we’ve provided links to a couple:

If you’re old fashioned like us, and opted for the traditional route then you installed X-Code. The react-native init function creates an Xcode project file inside the ios folder in your new project’s directory. Simply open this up using Xcode and you are off to the races and ready to build/run your project at will.

There was only one minor gotcha that reared it ugly head while trying to get our application up and running. The React Native Packager runs underneath node and requires a port for its functionality. The default port that it runs on is 8081, and there is a chance that you could have a process already running on that port so your application will not be able to run. So before you try and run your Xcode project for the first time it is worth doing a quick check to make sure that port 8081 is free using: 

sudo lsof -i :8081

Other than this minor inconvenience you should be all set for development!

After an hour or two of playing with React Native and building a pretty simple app, the power and simplicity of this framework became clear to us. First and foremost it was very refreshing to only have to run one or two npm commands and then be writing code in minutes afterwards. Setup was quick and painless which is always appreciated. During development we immediately noticed that developing our app felt just like developing for the web. Laying out the application was done using the CSS flex box, and was both quick and intuitive. Additionally, and probably more importantly, the framework just works. The UI components are native UIViews so naturally they look, feel, and behave the same as normal native components. We would definitely consider using React in the future and look forward to seeing how it improves and progresses from here.

Javascript, Angular, or how I learned to love the bomb

By Phil Booth | Leave a Comment on Javascript, Angular, or how I learned to love the bomb

Enter the dragon

Interning with Setfive for the last couple of months has given me the opportunity to both work with numerous, modern-day technologies and transition into being a more confident, organized developer. One technology in particular that I’ve had the chance to learn about and use extensively during my internship here is the JavaScript programming language. Programming with an MVC framework like AngularJs has shown me the many facets of the JavaScript language and given me an interesting foray into learning JavaScript from the top down.

Coming from a mainly C++ background the first thing I noticed about JavaScript was its flexibility. The mixture of the dynamic typing, along with the support of multiple programing paradigms (Functional programming and Imperative programming) gave me a freedom to program any way that I saw fit and do things that I never even thought were possible in a language with a stricter typing system. However this freedom definitely comes with a price, sometimes making even moderately complex programs both hard to navigate, and even harder to debug.

This lack of an inherent language structure, though initially causing a few headaches and even more than a few fist shaking bugs has, over time, helped ingrain both strong development skills as well an inherent need to intuitively structure code. Both of these skills are at the forefront of programming with AngualrJs.

Leveling up

My experience with Angularjs has definitely been an incredibly positive one, although the beginning was quite rough. Actually, the beginning was fairly easy however, the step after the “hello (insert name bound from text box)” step was actually the rough one. With Angular, easy things are very easy but can become difficult very quickly as soon as you are trying to develop something that is not so rudimentary.

My first experience with Angular came in the form of writing unit tests for a project that was under development here during the Summer. I spent a couple of weeks delving through a large Angular application written by one of our head engineers. After my introduction to the framework I was given the chance to use it for some development while working on some frontend modules for the Rotorobot site. These are the main challenges that I ran into while trying to learn Angular Js.

The Tough Stuff

The first challenge that I had to overcome was understanding the structure of the Angular framework. Being very inexperienced with the design pattern of Model View Controller (MVC) made this aspect the hardest part of learning Angular. Angular implements MVC by having the developer split their application into MVC components and then acts as a pipeline connecting them together. It is a robust MVC framework that promotes complicated integration of different components into whole applications. If you don’t have a sense of how the pieces fit together then the “Set it and forget it” or 2-way data-binding nature of the framework can easily turn into one of your biggest headaches.

The second challenge with learning Angular was understanding the way that scoping works within the context of the framework. What possibly could have possessed the developers of Angular to name one of the most confusing parts of their framework the same name as one of JavaScript’s most confusing aspects –who knows. In order to use some of the most powerful features of Angular such as, custom directives, it was really important to understand how scoping works or else it’s virtually impossible to link programs together. Developers would be left with a pile of stateless, independent components responsible for various tasks of the application rather than a connected working whole.

The last major challenge with learning Angular was thinking in terms of modularity. With things like custom directives, and the various service providers being at its core, the Angular framework really helps to promote code modularity. And breaking your application into small, reusable, testable components. This concept is huge in Angular, and I felt like seeing it work within the context of the framework has made me a better JavaScript programmer overall.

Overall I thoroughly enjoyed my time with Angularjs and felt like I learned a significant amount about structuring web-based applications. I am glad to have been given some experience with a modern JavaScript MVC framework and I wouldn’t hesitate to use Angular again in the future.