Kotlin Multiplatform Cheat Sheet

// commonMain/kotlin/Platform.ktexpect class Platform() {    val name: String}expect fun getPlatform(): Platform// androidMain/kotlin/Platform.android.ktactual class Platform actual constructor() {    actual val name: String = "Android ${android.os.Build.VERSION.SDK_INT}"}actual fun getPlatform(): Platform = Platform()// iosMain/kotlin/Platform.ios.ktactual class Platform actual constructor() {    actual val name: String = UIDevice.currentDevice.systemName()}actual fun getPlatform(): Platform = Platform()

kotlin {    androidTarget()    iosX64()    iosArm64()    iosSimulatorArm64()    jvm("desktop")    sourceSets {        val commonMain by getting {            dependencies {                implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.8.0")            }        }        val androidMain by getting        val iosMain by creating {            dependsOn(commonMain)        }        val iosX64Main by getting { dependsOn(iosMain) }        val iosArm64Main by getting { dependsOn(iosMain) }    }}

// commonMain: shared business logic, no platform APIsclass UserRepository(private val api: ApiClient) {    suspend fun getUser(id: String) = api.fetchUser(id)}// commonMain can use expect declarations for anything platform-specific,// like file storage, HTTP engines (via Ktor's multiplatform client), or// platform-specific date/time formatting.// androidMain / iosMain: actual implementations, plus platform-only code// that isn't part of any expect declaration at all (e.g. Android Activity// classes or iOS SwiftUI views) lives entirely in its own source set.