JsonUnionEncoding.FSharpLuLike mismatch with fsharplu for single field union cases

[johlrich]

There's a mismatch on the encoding for union cases with a single field when using JsonUnionEncoding.FSharpLuLike. In cases where field count = 1 FSharpLu will just serialize the object instead an array with the one object.

Example for type SingleFieldCase = Single of string

Current FSharpLuLike encoding: {"Single":["hi"]}

Actual FSharpLu encoding: { "Single": "hi" }

I was not sure what the best way to approach this would be wrt affecting other encoding options. Happy to help implement any acceptable changes as needed.

[Tarmil]

Good catch! I think a good way to fix this would be to add an option to the JsonUnionEncoding enum, something like SuccintSingleFieldUnions = 0x10_00, that enables this behavior, and then FSharpLuLike would be 0x16_02.