Issue #42
Hi there,
Welcome to the 42nd issue, the answer to life and everything! This time, among other topics, there's a couple of tips about code and project setup improvements that facilitate speed - faster app launch, execution speed, and build times. Enjoy!
By the way, next issue will arrive on Tuesday, February 14th 💌
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Speeding app launch by improving code
A story about DoorDash improving their app launch time by auditing and improving code that's run during startup. Among other things, I was surprised how small changes make a big difference. For example, shifting from using String(describing:) to ObjectIdentifier boosted their launch time by 11%!
Filip Busic
Optimizing code performance
In this article you'll learn about even more small tweaks you can make to Swift code that would optimize for performance. I love how Avi includes the "price table" - the tradeoffs for each of the suggestions 👍
Avi Tsadok
Improving linting speed
Many of us use SwiftLint, and if you don't - it's a good idea to add it to the project.
Xcode 14 introduced a new warning, notifying us of a previously non-obvious fact - with the default setup, SwiftLint is ran on all source files in the project, even for incremental builds, when only one file was changed, for example.
So the incremental builds are slower than they could be - and on large projects this could be a noticeable difference.
So what can we do? If we just accept Xcode's suggestion, it will just silence the warning. Gladly the warning is useful here - it hints that we can configure it to work together with incremental builds, so it would only run on files that changed.
Steven here made a detailed write-up on how to configure this in Xcode, so you get faster incremental builds:
steven851007Formatting JSON strings
A small reminder that we can write JSON strings rich with quotation marks without escaping them - keeping the readability of the JSON.
The best ways to streamline working with JSON strings in Swift that I've been using:
— Catalin Patrascu (@cpatrascudev) February 1, 2023
• Use triple quotes
• Use the pound character
What others would you add?#iosdev #swiftlang pic.twitter.com/veUZnxTk85
On testing
It's not the first time I share one of Jason's thoughts. I find most of what he writes extremely insightful. If you're still on Twitter, make sure to give him a follow!
When writing a test for a class, don't make it your focus to test all the class's methods.
— Jason Swett (@JasonSwett) February 1, 2023
Instead, make it your focus to test all the class's behaviors.
This way the tests will be more likely to possess an important quality: meaning.
✌️
Alright, that's it for today! Thank you to Paste for sponsoring this issue (and here's their iOS/macOS developer job posting).
I'm curious if you found one of the tips particularly interesting - let me know by replying to this email!
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