Node js STL vector of strings support broken

[0-issue]

Hi,

The support for STL vector of strings is broken. Here's an example:

Works fine: function reverse_str. It takes one std string as input, and returns another std string.
Doesn't work fine: function reverse_each_str. It takes STL vector of strings as input, and returns another STL vector of strings.

File example.i:

%module example
 %{
 /* Includes the header in the wrapper code */
 #include <chrono>
 #include <iostream>
 #include <cstdlib>
 #include <cstdio>
 #include <unistd.h>
 using namespace std;
 using namespace std::chrono;
 %}

 %include "cpointer.i"
 %include "std_string.i"
 %include "std_vector.i"
 %include "typemaps.i"

 %template(VectInt) std::vector<int>;
 %template(VectString) std::vector<std::string>;
 %template(VectVoidPtr) std::vector<void*>;

 %inline %{
std::string reverse_str (std::string arg) {
    std::string reverse_arg;
    reverse_arg = std::string(arg.rbegin(),arg.rend());
    return reverse_arg;
}

std::vector<std::string> reverse_each_str(std::vector<std::string> v) {
    std::vector<std::string> w(v);
    for (unsigned int i=0; i<w.size(); i++)
        w[i] = std::string(w[i].rbegin(),w[i].rend());
    return w;
}

%}

File binding.gyp:

{
        'targets': [
                {
                        'target_name': 'example',
                        'sources': [ 'example_nodejs.cxx' ],
                        'cflags': ['-std=c++11'],
                        'cflags!': [ '-fno-exceptions' ],
                        'cflags_cc!': [ '-fno-exceptions' ],
                }
        ]
}

Example test.js:

#!<path_to_your_node_install_dir>/bin/node
var example = require("<path_to_example_dir>/example/build/Release/example")

var arguments = ['hello', 'world'];

console.log(example.reverse_str(arguments[0]));
console.log(example.reverse_each_str(arguments));

Shell commands:

swig -javascript -node -c++ -outdir example -o example/example_nodejs.cxx example.i
cd example
node-gyp --python <path_to_python2.7> --nodedir <path_to_your_node_install_dir> configure build
cd <path_to_test.js>
./test.js

I think --nodedir <path_to_your_node_install_dir> is optional, I had to add a path to point to correct node version (I tried multiple: 6.x, 8.x...). Also the --python <path_to_python2.7> is optional if you are using not using python 3 or above.

Also, I applied patch from #968 as I had node 8 installed, that got me going with node 8, and function reverse_str works, but reverse_each_str doesn't.

Thanks for this tool & help in advance. Have used SWIG with other languages, its a great tool.

Best,

Aman

[frans-fuerst]

I have the same issue. I just tried v4.0.0 from master @ 67f5ade7ad03f15a2811190df899196dbf5a12fe. When I print the result of a function returning a vector of string in JavaScript I just get
_exports_StringVector {}

[microcai]

confirms

[kbobrowski]

it works when converting to and from swig object:

var example = require("./build/Release/example")

var args = ['hello', 'world'];

console.log(example.reverse_str(args[0]));

var cArgs = new example.VectString(args.length)
for (var i=0; i<args.length; i++) {
  cArgs.set(i, args[i]);
}

var cVectString = example.reverse_each_str(cArgs);

var jsVectString = []
for (var i=0; i<cVectString.size(); i++) {
  jsVectString.push(cVectString.get(i))
}
console.log(jsVectString);

[ojwb]

When I print the result of a function returning a vector of string in JavaScript I just get
_exports_StringVector {}

That sounds like #653.