#include <emscripten/bind.h>
#include <iostream>

using namespace emscripten;

// Define constant being exposed
const double PI = 3.141592653589793238463;

// Expose PI constant to JS
EMSCRIPTEN_BINDINGS(Module)
{
    constant("PI", PI);
}

Return pointer to a variable
-----------------------------
#include <emscripten/bind.h>
#include <iostream>

using namespace emscripten;

// Data being sent to JS via TypedArray
// Has length of 309
char* data = "sadiofhsdoithqrp;lstgnpoulgdfjna;gunhdfso;gljkpuahsptr hnweqopmftopirsmgrstm,rwheiopt,w   qgtiop  rno enbrgorlgnvolfsd;cgbunpqerbgnjla;sdfbgoufld;grqeibtgr pvmoqmwprul;tlmv  qweuumpvthwuioetqvlqmw;etvumqhtvuiormthvqeuoitv,uhreamoithgl;hlajghknfihgrel;agheirgdoga;lhe;rhgoueobmopiamvrotmq3498vtm4p35ty;vmqa;tvyn ";

// Method being registered to JS
// Returns handle to 'data'
//
// 'val' is defined by Emscripten and is used to return JS objects from C++
val getAlotOfData()
{
    // In this particular instance,
    // this method will return an Int8Array with with a handle to the 'data' variable's memory
    // This means that you are able to edit the variable in JS because its essentially passing a
    // pointer
    //
    // But Emscripten will return the JS TypedArray datatype makes the most sense
    return val(typed_memory_view(309, data));
}

// Register 'getAlotOfData()'
EMSCRIPTEN_BINDINGS(Module)
{
    function("getAlotOfData", &getAlotOfData);
}