Sharing [Kotlin code across platforms] is caring!

Sharing code across platforms is one of the most annoying "unsolved problems" when developing a product: an eternal struggle between re-writing everything multiple times and jumping through plenty of hoops to be able to re-use some core business logic. This session is going to illustrate how Kotlin is being used to solve this problem at Clue in order to share code between Android, iOS and the backend, including all the challenges, lessons and tricks learned along the way.

Presented at KotlinConf 2017

Transcript

1. @workingkills Eugenio Marletti Sharing [Kotlin code across platforms] is caring! KotlinConf
2. “app” “ ” “ ” “ ” “ ”
3. “app” iOS Android frontend backend tools “ ” “ ” “ ” “ ”
4. sharing
5. code sharing
6. code sharing
7. business logic sharing
8. bugs sharing
9. bugs sharing
10. fixes sharing
11. effort sharing
12. C++ J2ObjC / GWT JavaScript
14. THE ALGORITHM™
15. THE ALGORITHM™ C++ ObjC++ JavaScript TypeScript
16. C++ ObjC++ JavaScript TypeScript iOS !" JavaScriptCore Android !" WebView
17. C++ ObjC++ JavaScript TypeScript iOS !" JavaScriptCore Android !" W ͊̊̏̃͑̽̃̕ ̘͖̯ 㸅 ̨͇̯ ̶ȩ̧̟̝͔ ͔͎̗̬̼̓̒̄̍̓͐̒̎̕ b̡̫̰͙͚͋͋̓́̇͟V ͐̇͞ ̓̿̔̿̓ ͒̚ ͟ ̨̭̳̱͕ ̵i ͒̅̉͊̌̇ ̡͓̰̲̳͟ ̥̯ ̯̦ę͕͔͉̜̗͔͎ ̔̍̀̏̌̕ ͢ ͟ w ̛͊͆̍͑ ̴̯̯̻̪̦
18. ? C++ ObjC++ JavaScript TypeScript iOS !" JavaScriptCore Android !"
19. THE ALGORITHM™ C++ ObjC++ JavaScript TypeScript Kotlin @fbecart Florent Bécart
20. multi-platform
21. header impl (before 1.2) -Xmulti-platform
22. header impl (before 1.2) -Xmulti-platform
23. expect actual (from 1.2) -Xmulti-platform
24. ANDROID WebView iOS JavaScriptCore BACKEND JS legacy.js
25. legacy-test.js ANDROID WebView iOS JavaScriptCore BACKEND JS legacy.js shared-test.kt shared.kt
26. legacy-test.js ANDROID WebView iOS JavaScriptCore BACKEND JS legacy.js shared-test.kt shared.kt
27. legacy-test.js ANDROID WebView iOS JavaScriptCore BACKEND JS legacy.js shared-test.kt shared.kt
28. legacy-test.js ANDROID WebView iOS JavaScriptCore BACKEND JS legacy.js shared.kt shared-test.kt
29. legacy-test.js ANDROID WebView iOS JavaScriptCore BACKEND JS shared.kt shared-test.kt JVM
30. /** * A day number, offset from 01/01/2012 !" export type Day = number
31. /** * A day number, offset from 01/01/2012 !" typealias Day = Int
32. class Value { constructor(value: Double) { this.value = value } val value: Double override fun toString(): String { return this.value.toString() } companion object { fun add(v1: Value, v2: Value): Value { return Value(v1.value + v2.value) } fun isZero(valueWithVariance: Value): Boolean { return .0 !!% valueWithVariance.value } fun subtract(v1: Value?, v2: Value?): Value { var value = .0 if (v1 !' null !& v2 !' null) { value = v1.value - v2.value } return Value(value) } } } export class Value { constructor(value) { this.value = value } readonly value: number toString() { return String(this.value) } static add = (v1: Value, v2: Value): Value !$ { return new Value(v1.value + v2.value) } static isZero = (valueWithVariance: Value): boolean !$ { return 0 !!% valueWithVariance.value } static subtract = (v1: Value, v2: Value): Value !$ { let value = 0 if (v1 !& v2) { value = v1.value - v2.value } return new Value(value) } }
33. < insert more talking here >
34. Eugenio Marletti @workingkills BIT.LY/SHARING-KOTLIN-IS-CARING