mix NAPI and v8/Nan within the same addon

[Flarna]

• Node.js Version: 12.x
• OS: All
• Scope (install, code, runtime, meta, other?): Native Addons
• Module (and version) (if relevant):

Are there any limitations in mixing NAPI and v8/NAN within the same native Addon?

There are some v8 APIs not available via NAPI like installing GC callbacks or reading inferred function name from a function object therefore I stick on v8/NAN for some corner cases but would prefer NAPI for the rest.

I would expect that at napi_handle_scope is also a v8 HandleScope. Is that true?
Is it possible to convert between napi_value and v8::Value?

[mhdawson]

We don't do anything to specifically prevent the combination however:

• Using N-API and then using some v8/NAN calls will obviously mean your compiled add cannot run
  with other version of Node. I also think it means you won't get the warning about ABI in-
  compatibility in the V8/NAN side which could result in crashes
• The N-API types are specifically opaque and we don't provide ways of converting them. From https://github.com/nodejs/node/blob/master/src/js_native_api_v8.cc#L2508 and https://github.com/nodejs/node/blob/master/src/js_native_api_v8.cc#L140 they do currently seem to be a simple recast but that is specifically NOT guaranteed and could change at any time. If there was a change you'd have to be willing to update your conversions.

[mhdawson]

If the list of things you can't do is small could you paste the list here.

[Flarna]

That's clear that I have to compiler per major node version as soon as I use NAN/v8. My intention is to get rid of as much as possible from using NAN/v8 simply because of easier maintenance.

Most likely the safer approach would be to register the addon via the legacy API as context aware addon (via NODE_MODULE_INITIALIZE) to ensure loading works only for matching version but then use NAPI for as much as possible.

If the list of things you can't do is small could you paste the list here.

I created following issues a while ago which should cover most cases: nodejs/abi-stable-node#295 and nodejs/abi-stable-node#296

I think CpuProfiler and HeapProfiler are meanwhile available from JS land via inspector.
For the others the result was more or less that they don't fit to NAPI.

[github-actions]

There has been no activity on this issue for 3 years and it may no longer be relevant. It will be closed 1 month after the last non-automated comment.

[mhdawson]

I'm going to close out this issue.

[Flarna]

completely forgot about this one. Using Napi and v8/NAN seems to work fine, at least I haven't run into issues.

One has to copy over the casting/conversion between Napi <==> v8 handles from node code but as long as this doesn't change there it works.

Main drawback here is that this setup accumulates the disadvantages of both worlds:

• Napi has higher overhead (might be don't care for a lot users)
• v8/Nan requires a binary per major node.js version

It's unlikely that all potential relevant v8 APIs will be available via Napi at any time so if one decide to go this path this mixed setup will likely not go away.