Objective-C

As a Engineering Manager & Director at SmartZip, I had a mix of front-end, back-end, #mobile engineers reporting to me.

Sprints after sprints, I noticed some inefficiencies on the MobileDev side. People working multiple sprints in a row on their Xcode / Objective-C codebase while some others were working on Android Studio. After which, QA & Product ensured both applications were in sync, on a UI/UX standpoint, creating addional work, which also happened to be extremely costly.

Our resources being so limited, my role was to stop this bleeding and keep my team productive and their time, valuable.

After some analysis, discussions, proof of concepts... etc. We decided to move to a single codebase using React Native so our velocity would increase.

After some initial investment, our initial assumptions were confirmed and we indeed started to ship features a lot faster than ever before. Also, our engineers found a way to perform this upgrade incrementally, so the initial platform-specific codebase wouldn't have to entirely be rewritten at once but only gradually and at will.

Feedback around React Native was very positive. And I doubt - for the kind of application we had - no one would want to go back to two or more code bases. Our application was still as Native as it gets. And no feature or device capability was compromised.

Excerpts from how we developed (and subsequently open sourced) Uber's cross-platform mobile architecture framework, RIBs , going from Objective-C to Swift in the process for iOS: https://github.com/uber/RIBs

Uber’s new application architecture (RIBs) extensively uses protocols to keep its various components decoupled and testable. We used this architecture for the first time in our new rider application and moved our primary language from Objective-C to Swift. Since Swift is a very static language, unit testing became problematic. Dynamic languages have good frameworks to build test mocks, stubs, or stand-ins by dynamically creating or modifying existing concrete classes.

Needless to say, we were not very excited about the additional complexity of manually writing and maintaining mock implementations for each of our thousands of protocols.

The information required to generate mock classes already exists in the Swift protocol. For Uber’s use case, we set out to create tooling that would let engineers automatically generate test mocks for any protocol they wanted by simply annotating them.

The iOS codebase for our rider application alone incorporates around 1,500 of these generated mocks. Without our code generation tool, all of these would have to be written and maintained by hand, which would have made testing much more time-intensive. Auto-generated mocks have contributed a lot to the unit test coverage that we have today.

We built these code generation tools ourselves for a number of reasons, including that there weren’t many open source tools available at the time we started our effort. Today, there are some great open source tools to generate resource accessors, like SwiftGen. And Sourcery can help you with generic code generation needs:

https://eng.uber.com/code-generation/ https://eng.uber.com/driver-app-ribs-architecture/

(GitHub : https://github.com/uber/RIBs )

We are using React Native in #SmartHome to share the business logic between Android and iOS team and approach users with a unique brand experience. The drawback is that we require lots of native Android SDK and Objective-C modules, so a good part of the invested time is there. The gain for a app that relies less on native communication, sensors and OS tools should be even higher.

Also it helps us set different testing stages: we use Travis CI for the javascript (business logic), Bitrise to run build tests and @Detox for #end2end automated user tests.

We use a microservices structure on top of Zeit's @now that read from firebase. We use JWT auth to authenticate requests among services and from users, following GitHub philosophy of using the same infrastructure than its API consumers. Firebase is used mainly as a key-value store between services and as a backup database for users. We also use its authentication mechanisms.

You can be super locked-in if you also rely on it's analytics, but we use Amplitude for that, which offers us great insights. Intercom for communications with end-user and Mailjet for marketing.

Basically, the trajectory was we had our iOS app, which started out native, right? It started as a native app, and then we realized you have to go through a review process and it’s slow, and at a very early stage, it made sense for us to make it a wrapped web view. Basically, the app would open, and it would be a web view inside of it that we could iterate on quickly and change very rapidly and not have to wait for app store view process to change it. It wasn’t totally a native experience, but it was as actually a pretty good experience and lasted for a very long time and was up until recently the foundation of our current mobile web experience, which is different from our app situation. So for a long time, basically, our app store iOS Instacart app was a wrapped web view of just our store, a condensed version of our store, which meant that we could add things. We could change sales. We could change the formatting. We could change the UI really fast and not have to worry about the app store review process.

This all changed about a year ago, I would like to say, at which point it became a totally native app. We felt comfortable enough with the product and all the features that we made it a native experience and made it a fully featured app. Objective-C