Bugfix/fix for correctly generating additional properties, added types for typescript

[mvarchdev]

Followup for PR #18164 - Optimising fix for additional properties. Added missing types in typescript. Updated tests for Java.

FYI: @TiFu (2017/07) @taxpon (2017/07) @sebastianhaas (2017/07) @kenisteward (2017/07) @Vrolijkx (2017/09) @macjohnny (2018/01) @topce (2018/10) @akehir (2019/07) @petejohansonxo (2019/11) @amakhrov (2020/02) @davidgamero (2022/03) @mkusaka (2022/04)

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[macjohnny]

I wonder if its a good idea to use unknown instead of any, since this probably breaks a lot of client code that accesses these values

[mvarchdev]

From the typescript perspective (ECMA standarts etc) it is better to use unknown, as it is exactly describe its state/type, which is unknown and you must check/know the type of it. IMO it make the code more error-free/robust in runtime as you will be forced to check the type.

[mvarchdev]

I can put it back to any but my linter and strict tsconfig settings do not like it, which is sign of not best typing.

[mvarchdev]

Or maybe, make use of config switch supportsES6 that when it would be true, it would use unknown instead of any

[macjohnny]

i would suggest to switch it back to any, in order not to break existing use cases.

[andreseloysv]

Consider using unknown instead of any here. The unknown type is safer because it requires us to perform explicit type checking before performing any operations on the value. This approach enhances type safety by ensuring we explicitly handle the variable's type before using it, thereby reducing the risk of runtime errors. Using unknown also improves code readability, as it clearly indicates that the type needs to be determined and handled carefully. This is especially beneficial in maintaining strict type safety practices across our TypeScript codebase.

[macjohnny]

to avoid a breaking change, i.e. to preserve backwards compatibility, I would argue we should keep using any and not change it to unknown

[andreseloysv]

I also think preserving backwards compatibility is really important. @mvarchdev , could you make the change so we can merge the fix?