Methods not returning after throwing Javascript exception

Open
#89 2 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
38/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
cpp, nodejs
Domain
api, backend

Research direction

Start in 6_object_wrap_example/node-addon-api/myobject.cc, especially the constructor path around line 28, and reproduce the no-argument call. Check the node-addon-api exception-handling guidance, then ensure the example stops after ThrowAsJavaScriptException so the documented error is preserved and the unwrapping case does not continue into a segmentation fault.

Written by the indexing model from the issue text.

Description

In the "6_object_wrap_example/node-addon-api", I tried to test what would happen when calling the constructor without arguments and I noticed that the actual exception thrown ("A number was expected") is different from the one in the code ("Number expected").

According to node-addon-api docs, when C++ exceptions are disabled you need to return immediately after calling ThrowAsJavaScriptException. So I would expect something like:

if (length <= 0 || !info[0].IsNumber()) {
    Napi::TypeError::New(env, "Number expected").ThrowAsJavaScriptException();
    return;
}

I think that the exception thrown is not the one from line 28 of myobject.cc, but another one thrown automatically when trying to convert the parameter to a number.

I tried to move one step further (following this tutorial) and unwrapping a Javascript object, and I get a segmentation fault when using the constructor without arguments because the code is not stopping after reaching the line with ThrowAsJavaScriptException.

Dominant language
C++
Stars
2.6k
Forks
602
No merged PRs in 30d

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from nodejs/node-addon-examples

All issues in nodejs/node-addon-examples

Similar issues

More C++ issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.