LightSpeed: Rewriting Messenger’s codebase for a faster, smaller, simpler app

Post by crtlaltdel » Tue, Mar 03, 2020, 4:01 PM UTC

danabramov wrote: post #282

Quite a few comments seem to imply Messenger was written in React Native, so I want to clarify this is not true. Messenger was a fully native app before the rewrite, too! RN isn’t the right tradeoff for Messenger — whose new core is written in plain C — but its use at FB in general is growing, with 750+ screens in RN. So the rumours of its death are greatly exaggerated. I think it’s great to have different options wi…

Post by therealdrag0 » Tue, Mar 03, 2020, 4:29 PM UTC

ashishb wrote: post #293

hvidgaard wrote: post #246

Earlier quoted context omitted.

How in the name of everything did they manage to write 1.7M lines of code for a messenger app? That is an astonishingly large code base! We're talking about an instant messenger app with heaps of features, having a LoC footprint 3.5% of the size of modern Windows.

LOC is proportional to the number of engineers on a project. All engineers have to justify their existence, so, they will write code.

Post by archagon » Tue, Mar 03, 2020, 5:19 PM UTC

ss3000 wrote: post #276

wodenokoto wrote: post #163

Earlier quoted context omitted.

I would love to read more about why large apps are so big. I currently work on a project that is much larger than I would expect it to be, both in terms of codebase and people, and while I don't know who to jank, I also don't understand why it has to be so big.

Part of it also comes from the tendency of large orgs to ship their org structure. It can oftentimes be worthwhile to have individual teams each fully "own" a piece of the product, and that also comes with the autonomy to choose to duplicate stuff that other teams might have already built rather than working with them and tweaking it to match their own specific new requirement. This significantly reduces communicatio…

Post by [deleted] » Tue, Mar 03, 2020, 8:05 PM UTC

therealdrag0 wrote: post #313

ashishb wrote: post #293

Earlier quoted context omitted.

LOC is proportional to the number of engineers on a project. All engineers have to justify their existence, so, they will write code.

I've never felt the need to justify my own existence. There's always been a longer backlog of work than my teams would ever get through and managers who appreciated the work getting done. Another plausible explanation is lack of code re-use and reinventing the wheel because you don't know someone else solved the same problem. Also correlates with number of engineers.

Post by jstimpfle » Tue, Mar 03, 2020, 8:42 PM UTC

pjmlp wrote: post #312

tomduncalf wrote: post #307

Earlier quoted context omitted.

Yes and no, I think that depends how deep you want to go. For your standard "show and update some content and make it look pretty" type app, I can tell you from both my own and others experience you don't really need much familiarity with the native platforms, other than how to use build tools etc. which are well detailed online. If you want to go deeper or have more specialised requirements, then you might need a de…

I can speak for Qt, Ionic and Cordova. Beyond "Hello World" all of them required me to get my hands dirty, at which point I was better off just doing C++ with native views, standard out of the box tooling available across all SDKs. Nowadays I rather go for PWAs, or plain mobile Web, unless it is something very special that requires OS APIs or hardware access.