Deserialization of enums without @Serializable annotation is extremely slow in Kotlin JS

[DaanVandenBosch]

I currently have some code that takes 3 seconds to deserialize an array of 4304 objects with 4 enum properties. When I turn the enum properties into String properties it takes about 120 milliseconds.

Annotating the enums makes it about as fast as the string version (every enum property adds about 10ms). Writing custom serializers for enums from a library is equally fast.

It seems like performance for annotated and non-annotated enums should be similar, or is that not possible?

Expected behavior

Good performance.

Environment

• Kotlin version: 1.4.31
• Library version: 1.1.0
• Kotlin platforms: JS
• Gradle version: 6.8.2
• Browser: Chrome