Factory function, companion function or extension ...

# codingconventions

[Marc Knaup]

Factory function, companion function or extension function? 🤔

1️⃣

fun CurrencyCode(value: String): CurrencyCode         // throws if invalid
fun CurrencyCodeOrNull(value: String): CurrencyCode?  // null if invalid

2️⃣

fun CurrencyCode.Companion.parse(value: String): CurrencyCode         // throws if invalid
fun CurrencyCode.Companion.parseOrNull(value: String): CurrencyCode?  // null if invalid

3️⃣

fun String.toCurrencyCode(): CurrencyCode         // throws if invalid
fun String.toCurrencyCodeOrNull(): CurrencyCode?  // null if invalid

[elizarov]

stdlib quite consistently uses 3️⃣ for such a case.