Passing arrays and objects from JavaScript to c++ in Web Assembly

Ok, I've been pounding against this for a bit. I'm more of a JavaScript and C# focused dev, but I have some experience in c++. My problem is

1. I need to find a simple way to take a Javascript object and pass it through WebAssembly to c++
2. I need to do the same with Javascript arrays
3. I probably need to do the same with Javascript arrays of Javascript objects

So starting with what I have tried on a simple array:

//c++int testArr(int * arrIn, int length){  int results = 0;  for(int i = 0; i < length; i++){    results += arrIn[i] + 1;  }  return results;}//javascriptlet arr = [20, 50, 90, 62, 98];console.log(wasmInstance.exports.testArr(arr, arr.length));

So that should take an array of integers, add them plus 1 (basically to test the loop). It returns 5. I expect it to return 325. So looking at typed arrays was the next logical step...

//c++int testArr(int * arrIn, int length){  int results = 0;  for(int i = 0; i < length; i++){    results += arrIn[i] + 1;  }  return results;}//javascriptlet arr = [20, 50, 90, 62, 98];let typedArray = new Int32Array(arr);//test 1console.log(wasmInstance.exports.testArr(typedArray, arr.length));//test 2console.log(wasmInstance.exports.testArr(typedArray.buffer, arr.length));

Test 1 returns, again, 5. Test 2 returns 0.

Now just to see if I can get c++ to return an array:

//c++int * test(){  int arr[] = {12, 32, 54, 31};    return arr;}//Javascriptconsole.log(wasmInstance.exports.test());

Returns -16. Kind of funky and probably due to pointer issues between the two. Now if I try this:

//c++int test(){  int arr[] = {12, 32, 54, 31};    return arr[0];}//Javascriptconsole.log(wasmInstance.exports.test());

Now it returns 12.

And so that is so far is as far as I have gotten on passing arrays, which for the most part does not seem possible. Now, passing objects. God help me. Please be kind on the c++ because its not my strongest language.

//c++class Vector3{  public:    float x;    float y;    float z;    Vector3(float X, float Y, float Z){      x = X;      y = Y;      z = Z;    }};int test(Vector3 position){    return position.x;}//javascriptlet position = {x: 21, y: 30, z: 12};console.log(wasmInstance.exports.test(position));

This returns 0 instead of 21;

And now for the unholy trinity, an array of javascript objects...

//c++class Vector3{  public:    float x;    float y;    float z;    Vector3(float X, float Y, float Z){      x = X;      y = Y;      z = Z;    }};Vector3 test(Vector3 positions[], int length){    return positions[0];}//javascriptlet positions = [{x: 21, y: 30, z: 12},{x:15, y: 24, z: 14}]console.log(wasmInstance.exports.test(positions, positions.length));

This returns undefined.

So the question is, am I messing up in c++, javascript, wasm, all 3, or what? I've spent 3 days scouring the internet looking for answers and the only thing I can find is declarations that this is possible with no examples or documentation to say HOW this can be done. The best documentation I've found is a DevRant, which still didn't give me an answer on this.

So is this possible and if so, are there any working examples I can follow OR is this not at all possible?