What is the problem this feature will solve?

The maximum open files limit is increased to maximum on POSIX platforms here

However, similar functionality is missing for Windows which causes issues with error "EMFILE: too many open files", specially when using webpack.

What is the feature you are proposing to solve the problem?

Use the Windows CRT API to increase the limit. The function is called _setmaxstdio - https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/setmaxstdio?view=msvc-170

Different versions of Windows support different limits, the default is 512 files with maximum possible number of 8192. My suggestion would be to use loop for probing the maximum possible value, similar to what is currently done for POSIX. I.e. something like that:

static constexpr int MIN_OPEN_FILES_LIMIT = 512;
static constexpr int MAX_OPEN_FILES_LIMIT = 8192;
static constexpr int STEP_OPEN_FILES_LIMIT = 512;
for (int i = MAX_OPEN_FILES_LIMIT; i > MIN_OPEN_FILES_LIMIT; i -= STEP_OPEN_FILES_LIMIT)
{
    if (_setmaxstdio(i) != -1)
        break;
}

What alternatives have you considered?

Unfortunately, it seems there are no alternatives which can raise the limit for process on OS level (like ulimit on some *nix OSes). The process itself have to request it.