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Luis Custodio

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This post is based on a point Duncan McGregor made on this brilliant video about Data Oriented Programming (with gradual typing in Kotlin).

Java doesn’t handle generics well - it’s dense, it’s verbose. It’s java. I was quick to assume that typescript would suffer from a similar pattern, but then… well no. It handles it fairly well:

Kotlin code

The ugly:

val places = data["places"] as List<Map<String, Any?>>

The solution

inline fun <reified T> JsonObject.required(key: String) = get(key) as T

val places = data.required("places")


Kotlin allows bytecode compilation with the same level of readability Key safety is the type casting validation on runtime.