swift_on_bundle_size.md

Integrating SourcePoint's Swift SDK into an Obj-C Project

Impact in bundle size

In order to evaluate what's the impact in bundle size our SDK written in Swift has, we've created a Obj-C project from scratch, archived it for development and released on App Store (TestFlight). We later on added the ConsentViewController (our SDK) to the project and repeated the proccess. Some observations:

• App Thinning was enabled and set to All compatible device variants in both releases.
• Cocoapods was used to manage dependencies.
• In the release that included our SDK, when archiving, the following option was enabled:

Strip Swift symbols
Reduce app size by stripping symbols from Swift standard libraries

• The project created was targeting iOS 8 and above

First Release

Device	Compressed	Uncompressed	App Store Download**
iPhone	169 KB	273 KB	453 KB
iPad	167 KB	261 KB	*
Universal	326 KB	564 KB	*

Second Release (with our SDK included)

Device	Compressed	Uncompressed	App Store Download**
iPhone	2,6 MB	7,5 MB	918 KB
iPad	2,9 MB	6,5 MB	*
Universal	5,5 MB	14,4 MB	*

* not tested

** Downloaded on an iPhone Xs running iOS 12.2

Conclusion

1. Although adding a Swift framework into the project, does bring a substantial amount of code, XCode and the App Store will do a pretty good job on stripping unused code from the final build.
2. For devices running newer versions of iOS, the final build gets considerably smaller since the OS already have some of the run time code embedded.
3. With the release of Swift 5 and Swift's ABI stability (and later module stability)

[...] applications written in Swift no longer need to be distributed with the Swift runtime libraries, reducing download size. [...] third parties will also be able to ship binary frameworks written in Swift.