Primitives (number, boolean, bigint)

Primitive datatypes like number, boolean or bigint can use platform-native datatypes directly. For example, a JS number is always a 64-bit double in C++, a Double in Swift, and a Double in Kotlin.

TypeScript

interface Math extends HybridObject<{ … }> {
  add(a: number, b: number): number
}

Swift

class HybridMath: HybridMathSpec {
  func add(a: Double, b: Double) -> Double
}

Kotlin

class HybridMath: HybridMathSpec() {
  fun add(a: Double, b: Double): Double
}

C++

class HybridMath : public HybridMathSpec {
  double add(double a, double b);
}

Primitives are very efficient and can be passed with little to no overhead, especially between C++ and Swift, and C++ and Kotlin.

bigint's actual type

A bigint is actually a variable-size type.

In Nitro, you have to explicitly choose Int64 or UInt64 as types, which map to bigint in JS.

If you need larger numbers than UInt64, you need to either implement a Big Integer library yourself, or bridge bigint values using strings.