internal interface IConstructor

[lahma]

Discussed in #1141

^{Originally posted by viceice April 22, 2022}
Was this intentional to no longer make that interface public? I use that for a custom type, which implements this interface.

jint/Jint/Native/IConstructor.cs

Line 5 in fe4ee89

internal interface IConstructor

I'm basicall doing something like this:

jint/Jint.Tests/Runtime/Domain/UuidConstructor.cs

Line 11 in fe4ee89

internal sealed class UuidConstructor : FunctionInstance, IConstructor

changed in v3.0.0-beta-2038 via

• Add Engine.Construct method #1047

[viceice]

Can we make those interfaces public again until a better solution is found?

[dan3988]

Could FunctionInstance not implement IConstructor, with a virtual implementation that throws a type error by default? That way IConstructor can be made internal and we can still create custom constructors by overriding that method.

[lahma]

@dan3988 what's your use case, I'd favor something simpler like the model I'm proposing in this PR. Building against IConstructor usually means that you are implementing the ECMA spec.

[dan3988]

@lahma I have some custom classes I've implemented similarly to the ECMA classes inside Jint/Native, where I have a separate C# class for the constructor, prototype and instance.

[lahma]

Sorry to sound like a broken record, but can you give a more specific example. Doing the constructor-prototype-instance route seems quite involved compared to what it would be if we could make the interop do the leg work.

[dan3988]

I've extracted some of the code from the project into a repo with some examples of javascript classes:

• WmDate
• WmTime
• Uuid

There are 30-40 classes implemented this way in our project. It was written this way as we wanted the following

• Classes in the script that inherit other custom classes, so that instanceof would work in our scripts
• Classes that have a constructor object, but are not instantiatable inside the script (like the Window constructor in a browser)
• A way of adding properties with a different name to the C# method / property
• A way of adding properties with symbol keys, such as Symbol.toPrimitive

[lahma]

@dan3988 excellent! thanks for taking the time to describe your use case, I'll try to delve into this and see if there is easier way or should we just open APIs again.

[viceice]

maybe a constructor base class is enough

[EnCey]

bump, I'm facing the same problem now 😅
my use case is to call async .NET methods, which I've gotten to work, but it blocks me from going the TypeReference route, at least I don't see how that would work.

A constructor base class could also set the Function.PrototypeObject, which is something the UuidConstructor example does and feels like a good default.