Designing Experiences

How We Develop Design Components in Rails Learn how we use Rails components to keep our code D.R.Y. (Don’t Repeat Yourself) and to implement UX design changes effectively and uniformly.. A little over a year ago, we rebranded our entire site . And we've even written on why we did it. We were able to achieve a polished and consistent visual identity under a tight deadline which was pretty great, but when we had our project retrospective, we realized there was a pain point that still loomed over us. We still lacked a good way to share markup across all our apps. We repeated multiple styles and page elements throughout the app to make the experience consistent, but we didn’t have a great way to reuse the common elements. We used Rails partials in an effort to keep the code DRY (Don’t Repeat Yourself) while sharing the same chunks of code and that got us pretty far, but it had its limitations. There were aspects of the page elements (our shared chunks) that needed to change based on their context or the page where they were being rendered. Since these contexts change, we found ourselves either altering the partials or copying and pasting their code into new views where additional context-specific code could be added. This resulted in app code (the content-specific code) becoming entangled with “system” (the base HTML) code. Aside from partials, there was corresponding styling, or CSS, that was being copied and sometimes changed when these shared partials were altered. This meant when the designs were changed, we needed to find all of the places this code was used to update it. Not only was this frustrating, but it was inefficient. To find a solution, we drew inspiration from the component approach used by modern design systems and JavaScript frameworks. A component is a reusable code building block. Pages are built from a collection of components that are shared across pages, but can be expanded upon or manipulated in the context of the page they’re on. To implement our component system, we created our internal gem, Style Closet. There are a few other advantages and problems this system solves too: We’re able to make global changes in a pretty painless way. If we need to change our brand colors, let’s say, we can just change the CSS in Style Closet instead of scraping our codebase and making sure we catch it everywhere. Reusable parts of code remove the burden from engineers for things like CSS and allows time to focus on and tackle other problems. Engineers and designers can be confident they’re using something that’s been tested and validated across browsers. We’re able to write tests specific to the component without worrying about the use-case or increasing testing time for our apps. Every component is on brand and consistent with every other app, feels polished, high quality and requires lower effort to implement. It allows room for future growth which will inevitably happen. The need for new elements in our views is not going to simply vanish because we rebranded, so this makes us more prepared for the future. How does it work? Below is an example of one of our components, the flash. A flash message/warning is something you may use throughout your app in different colors and with different text, but you want it to look consistent. In our view, or the page where we write our HTML, we would write the following to render what you see above: Here’s a breakdown of how that one line, translates into what you see on the page. The component consists of 3 parts: structure, behavior and appearance. The view (the structure): a familiar html.erb file that looks very similar to what would exist without a component but a little more flexible since it doesn’t have its content hard coded in. These views can also leverage Rails’ view yield functionality when needed. Here’s the view partial from Style Closet: You can see how the component.message is passed into the dedicated space/ slot keeping this code flexible for reuse. A Ruby class (the behavior aside from any JavaScript): the class holds the “props” the component allows to be passed in as well as any methods needed for the view, similar to a presenter model. The props are a fancier attr_accessor with the bonus of being able to assign defaults. Additionally, all components can take a block, which is typically the content for the component. This allows the view to be reusable. CSS (the appearance): In this example, we use it to set things like the color, alignment and the border. A note on behavior: Currently, if we need to add some JS behavior, we use unobtrusive JavaScript or UJS sprinkles. When we add new components or make changes, we update the gem (as well as the docs site associated with Style Closet) and simply release the new version. As we develop and experiment with new types of components, we test these bigger changes out in the real world by putting them behind a feature flag using our open source split testing framework, Test Track. What does the future hold? We’ve used UJS sprinkles in similar fashion to the rest of the Rails world over the years, but that has its limitations as we begin to design more complex behaviors and elements of our apps. Currently we’re focusing on building more intricate and and interactive components using React. A bonus of Style Closet is how well it’s able to host these React components since they can simply be incorporated into a view by being wrapped in a Style Closet component. This allows us to continue composing a UI with self contained building blocks. We’re always iterating on our solutions, so if you’re interested in expanding on or solving these types of problems with us, check out our career page! Addition information Since we introduced our internal Rails component code, a fantastic open-source project emerged, Komponent, as well as a really great and in-depth blog post on component systems in Rails from Evil Martians.

Supporting Face ID on the iPhone X We look at how Betterment's mobile engineering team developed Face ID for the latest phones, like iPhone X. Helping people do what’s best with their money requires providing them with responsible security measures to protect their private financial data. In Betterment’s mobile apps, this means including trustworthy but convenient local authentication options for resuming active login sessions. Three years ago, in 2014, we implemented Touch ID support as an alternative to using PIN entry in our iOS app. Today, on its first day, we’re thrilled to announce that the Betterment iOS app fully supports Apple’s new Face ID technology on the iPhone X. Trusting the Secure Enclave While we’re certainly proud of shipping this feature quickly, a lot of credit is due to Apple for how seriously the company takes device security and data privacy as a whole. The hardware feature of the Secure Enclave included on iPhones since the 5S make for a readily trustworthy connection to the device and its operating system. From an application’s perspective, this relationship between a biometric scanner and the Secure Enclave is simplified to a boolean response. When requested through the Local Authentication framework, the biometry evaluation either succeeds or fails separate from any given state of an application. The “reply” completion closure of evaluatePolicy(_:localizedReason:reply:) This made testing from the iOS Simulator a viable option for gaining a reasonable degree of certainty that our application would behave as expected when running on a device, thus allowing us to prepare a build in advance of having a device to test on. LABiometryType Since we’ve been securely using Touch ID for years, adapting our existing implementation to include Face ID was a relatively minor change. Thanks primarily to the simple addition of the LABiometryType enum newly available in iOS 11, it’s easy for our application to determine which biometry feature, if any, is available on a given device. This is such a minor change, in fact, that we were able to reuse all of our same view controllers that we had built for Touch ID with only a handful of string values that are now determined at runtime. One challenge we have that most existing iOS apps share is the need to still support older iOS versions. For this reason, we chose to wrap LABiometryTypebehind our own BiometryType enum. This allows us to encapsulate both the need to use an iOS 11 compiler flag and the need to call canEvaluatePolicy(_:error:) on an instance of LAContext before accessing its biometryType property into a single calculated property: See the Gist. NSFaceIDUsageDescription The other difference with Face ID is the new NSFaceIDUsageDescriptionprivacy string that should be included in the application’s Info.plist file. This is a departure from Touch ID which does not require a separate privacy permission, and which uses the localizedReason string parameter when showing its evaluation prompt. Touch ID evaluation prompt displaying the localized reason While Face ID does not seem to make a use of that localizedReason string during evaluation, without the privacy string the iPhone X will run the application’s Local Authentication feature in compatibility mode. This informs the user that the application should work with Face ID but may do so imperfectly. Face ID permissions prompt without (left) and with (right) an NSFaceIDUsageDescription string included in the Info.plist This compatibility mode prompt is undesirable enough on its own, but it also clued us into the need to check for potential security concerns opened up by this forwards-compatibility-by-default from Apple. Thankfully, the changes to the Local Authentication framework were done in such a way that we determined there wasn’t a security risk, but it did leave a problematic user experience in reaching a potentially-inescapable screen when selecting “Don’t Allow” on the privacy permission prompt. Since we believe strongly in our users’ right to say “no”, resolving this design issue was the primary reason we prioritized shipping this update. Ship It If your mobile iOS app also displays sensitive information and uses Touch ID for biometry-based local authentication, join us in making the easy adaption to delight your users with full support for Face ID on the iPhone X.