In the documentation for Qt for WebAssembly, under the Asyncify JSPI (JavaScript Promise Integration) section, it states that JSPI can be enabled by adding:

target_link_options(<your target> PUBLIC -sJSPI)

I am doing it like this: set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -sJSPI")

However, JSPI was only introduced in Emscripten 3.1.59, while the documentation states that Qt 6.8 was built using Emscripten 3.1.56 and recommends using the same version. As a result, attempting to enable JSPI with this setup leads to errors stating that JSPI does not exist.

There should be clarification on which Emscripten version is required to enable JSPI or whether we should use ASYNCIFY=2 instead.