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https://github.com/yhkaplan/swift-migration-presentation-2019-07-30
Presentation on migrating from Objective-C to Swift
https://github.com/yhkaplan/swift-migration-presentation-2019-07-30
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Presentation on migrating from Objective-C to Swift
- Host: GitHub
- URL: https://github.com/yhkaplan/swift-migration-presentation-2019-07-30
- Owner: yhkaplan
- Created: 2019-07-30T04:29:31.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2019-07-31T14:03:45.000Z (over 5 years ago)
- Last Synced: 2024-11-06T05:42:20.378Z (3 months ago)
- Homepage:
- Size: 475 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
slidenumbers: true slide-transition: true
# [fit] The Great Swift Migration
---
# [fit] Self Intro
---
- Name: Josh Kaplan
- Company: GMO Pepabo
- App: minne
- Strengths: English
- Hobbies: Collecting Xcode versions
^ From the US
^ Pepabo's just down the street
^ minne, Japan's largest handmade marketplace
---
# [fit] 30,000 lines of Obj-C
^ 1.5 years
^ 3-4 people
---
# [fit] Why?
---
- Future proofing
- Safety
- Productivity with features like generics, etc
- Security
^ And until what point: just enough to be useful, 92% in our case
^ Security: being able to use latest version of libraries
^ SwiftUI, etc
---
# [fit] How?
---
# [fit] Modernize Objective-C
^ Models in particular
^ You're using ARC, right?
^ Nullability Annotations and Lightweight Generics
^ Why, how
---
```objectivec
@property (nonatomic, nonnull) NSArray *creators;
@property (nonatomic, nonnull) MICartPayment *payment;
@property (nonatomic, nonnull) MIAPIClient *client;
@property (nonatomic, nullable) MICoupon *coupon;
```
^ Review of lightweight generics
^ No compiler checks w/o annotations
---
# Check nullability in current Swift code
```swift
let num: Int? = nil
"\(num)" // String interpolation produces a debug description for an optional value
```
^ The dreaded "Optional()"
---
# Choosing which areas to migrate
- First, modernize models
- Then, ViewControllers and ViewModels/Presenters
- Work on feature/module basis
- Avoid converting code that is then used in obj-c
- Cells and smaller views can wait
^ Convert your business logic
^ Calling Swift from obj-c is painful because of feature differences like enums, generics, structs, etc
^ Calling modern obj-c is much less painful
---
# [fit] Details
---
# [fit] Steps
---
1. Move properties in m file to header and add annotations
2. Make Swift file and make extension
3. Migrate non-lifecyle methods and commit for each method
4. Make temporary method for lifecycle and IBAction method contents
5. Migrate lifecycle methods and properties
6. Update storyboard
^ Separate commits for each method is great for when there's a bug
^ Being able to compile and run your app w/ each commit is best practice
---
# [fit] Points
---
- Only *minor* refactoring
- Writing tests first helps
- Communicate with team to prevent conflicts
- Things like major renaming should be in separate PRs to make review easier
- Set goals and monitor progress with tools like *tokei*
^ Trying to make the logic significantly different while migrating makes reviews harder and makes it difficult to prevent bugs from entering
^ Running relevant tests on each commit allows for peace of mind
^ "brew install tokei", faster than cloc
---
# [fit] Bonus: Migrating to SwiftUI
---
- Small components
- Use Xcode Preview now
- Fewer dependencies
- Swift 😉
^ Talked w/ Apple engineers about this
^ Xcode Preview works with UIKit too, just need to make views/VCs conform to a protocol
^ Dependencies aren't bad, but unmaintained ones are a burden