Copy JS Int32Array to Emscripten heap for passing as C array

_arrayToHeap.js

function _arrayToHeap(typedArray){
  var numBytes = typedArray.length * typedArray.BYTES_PER_ELEMENT;
  var ptr = Module._malloc(numBytes);
  var ptr_i32 = ptr >> 2; // divide byte offset by 4 to account for 4-byte int pointer
  var heapBytes = Module.HEAP32.subarray(ptr_i32, ptr_i32 + typedArray.length);
  heapBytes.set(typedArray);
  return heapBytes;
}