Add deleteLater() and setDelayFunction(...) to TypeScript definitions and make them official API

[arnog-ms]

emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.1.68-git
clang version 20.0.0git
Target: wasm32-unknown-emscripten
Thread model: posix
InstalledDir: /opt/homebrew/Cellar/emscripten/3.1.68/libexec/llvm/bin

We are using the deleteLater() function a lot in our TypeScript codebase to not forget to delete a short lived reference. This works quite well. The only drawback is that we have to patch the generated TypeScript definitions to include the deleteLater() function for each interface that also has the delete() function. And we patch the MainModule export to include the setDelayFunction(...) definition, so that we can set the delay function at MainModule instantiation.

It would be great, if these two could be added to the generated TypeScript definitions and also be made an official API.

[sbc100]

I believe if you want to have setDelayFunction exported you should add it to EXPORTED_RUNTIME_METHODS. This should result it being part of the module definition.

[sbc100]

It looks like we were exported some functions under the hood so setDelayFunction was being made available, even if it wasn't needed. I'm fixing that in #22705.

Regarding deleteLater, that looks like maybe a different issue. @brendandahl should be declaring these methods in the generated TS?

[arnog-ms]

I tried to add -sEXPORTED_RUNTIME_METHODS=setDelayFunction but received the following warning

warning: invalid item in EXPORTED_RUNTIME_METHODS: setDelayFunction
em++: warning: warnings in JS library compilation [-Wjs-compiler]

Is this due to the bug mentioned above? If so, should this work with 3.6.19 once it's released?

[sbc100]

Thats odd. Are you passing --bind? Is seems to work fine for me:

((3.1.68)) $ ./emcc test/hello_world.c -sEXPORTED_RUNTIME_METHODS=setDelayFunction --bind

[arnog-ms]

This is an excerpt from our cmake file. -lembind is equivalent to --bind, isn't it?

if(${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
    set(CMAKE_EXECUTABLE_SUFFIX ".js")

    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} --no-entry --emit-tsd wasmtypes.d.ts")

    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -sWASM=1 -sEXPORT_ES6=1 -sMODULARIZE=1 -sEXPORTED_RUNTIME_METHODS=setDelayFunction -lembind -sEXPORT_NAME=ManagerModule")
endif()

[brendandahl]

I think that is hitting the bug about runtime exports combined with emit-tsd. That is fixed #22705

[sbc100]

Ah yes, try emsdk install tot to get ta build with that change in.

[arnog-ms]

OK, I will give that a try in the next few days.

If I understand correctly, this would only solve the setDelayFunction export, right? So the deleteLater is not covered by this?

[brendandahl]

Correct, I'll add a separate fix for that.

[arnog-ms]

Thank you very much!

[sbc100]

Yes setDelayFunction is just a normal library function so should be part of your generated TS once its exported normally.

deleteLater looks like its a method that exists on all embind objects. Should we be declaring this (and other builtin methods)? Is it possible for a user method to collide with one of these builtin method names?

[arnog-ms]

I think, at the moment, only delete is exported automatically. For me it would be great to also export deleteLater automatically.

Together with setDelayFuntion this makes it much easier to not forget to delete a reference.

It might also be worthwile to set the delay function to setTimeout(fn, 0) by default.

[brendandahl]

Yes setDelayFunction is just a normal library function so should be part of your generated TS once its exported normally.

deleteLater looks like its a method that exists on all embind objects. Should we be declaring this (and other builtin methods)? Is it possible for a user method to collide with one of these builtin method names?

I think we just need to update the defaults. These definitions were mostly from the previous TS project, so I'm not sure why they're missing. The names could collide, but that should really be an error.

[arnog-ms]

I tested with 3.1.69 and I can see the export of setDelayFunction in the .d.ts file. Thanks for that. :-)