Example Bun FFI C++

addons.ts

import { dlopen } from 'bun:ffi';
// build C++ in Linux -> g++ -shared -o test.so ./test.cpp -std=c++23 -lstdc++ -fPIC
export const addons = dlopen('test.so', {
  create: {
    args: ['callback'],
    returns: 'pointer',
  },
  summon: {
    args: ['pointer', 'pointer'],
    returns: 'void',
  },
  destroy: {
    args: ['pointer'],
    returns: 'void',
  },
});

test.cpp

struct Memo {
    void(*javascript)(char *);
};

class Example {
    private:
        Memo * memo;
    public:
        explicit Example(void(*javascript)(char *));
        ~Example();
        void execute(char* args);
    
};

Example::Example(void(*javascript)(char *)){
    this -> memo = new Memo{javascript};
}

Example::~Example(){
    delete this -> memo;
}

void Example::execute(char* args){
    this -> memo -> javascript(args);
}


extern "C" {
    Example * create(void(*javascript)(char*)){
        auto * example = new Example(javascript);
        return example;
    }

    void summon(Example * example, char* args){
        example -> execute(args);
    }

    void destroy(Example * example){
        delete example;
    }

}

test.spec.ts

import { addons } from './addons';
import { describe, it, expect, afterAll } from 'bun:test';
import { CString, JSCallback } from 'bun:ffi';

const summon = new JSCallback(ptr => expect(new CString(ptr).toString()).toEqual('Lorem is simple'), {
  args: ['pointer'],
  returns: 'void',
});

const example = addons.symbols.create(summon.ptr);

describe('Integration C++ test', () => {
  afterAll(() => {
    addons.symbols.destroy(example);
    summon.close();
    addons.close();
  });
  it('should be possible create a Example', () => {
    expect(example).not.toEqual(null);
  });
  it('should be possivel  call a summon of Example', () => {
    expect(addons.symbols.summon(example, new TextEncoder().encode('Lorem is simple\0'))).not.fail();
  });
});

test.ts

import { JSCallback } from 'bun:ffi';
import { addons } from './addons';

const summon = new JSCallback(ptr => console.log(new CString(ptr)), {
  args: ['pointer'],
  returns: 'void',
});

const example = addons.symbols.create(summon.ptr);
addons.symbols.summon(example, new TextEncoder().encode('Lorem is simple\0'));
addons.symbols.destroy(example);
summon.close();
addons.close();