Duktape Example

function testClass(){
   this.hInst=0;
	this.ReadAll = function(){
		print('testClass.ReadAll() called'); 	
	}
}

var ts = nativeFunc('file.txt');
print('ts=' + ts);
print('ts.hInst = ' + ts.hInst);
ts.ReadAll();
ts=null;
print('test complete');

//ref: http://stackoverflow.com/questions/30296953/export-c-class-to-duktape

#include "./duk/duktape.h"
#include <conio.h>

/*
output:
	nativefunc(file.txt) returning a new testClass instance
	ts=[object Object]
	ts.hInst = 12345
	testClass.ReadAll() called
	textstream instance 12345 released!
	test complete
*/

duk_ret_t js_testClass_dtor(duk_context *ctx)
{
	int hInst = 0;

    // The object to delete is passed as first argument
	//retrieve this.hInst numeric value
    duk_get_prop_string(ctx, 0, "hInst");
	hInst = duk_to_number(ctx, -1); 
    duk_pop(ctx); 

	printf("textstream instance %d released!\n", hInst);
    return 0;

}

int nativeFunc(duk_context *ctx) {
	int i;
	const char* arg0 = 0;
	//int n = duk_get_top(ctx);  //arg count

	arg0 = duk_safe_to_string(ctx, 0);

	printf("nativefunc(%s) returning a new testClass instance\n", arg0);

	//create a new testClass javascript object instance
	duk_get_global_string(ctx, "testClass"); 
	duk_new(ctx, 0); 

	//set this.hInst = 12345
	duk_push_number(ctx, 12345); 
	duk_put_prop_string(ctx, -2, "hInst"); 

	//register a C function to run when js obj released
	duk_push_c_function(ctx, js_testClass_dtor, 1);
	duk_set_finalizer(ctx, -2);	 

	return 1;
}

int main(int argc, char *argv[]) {

	duk_context *ctx = duk_create_heap_default();

	char* mClass = "function testClass(){\n"
				"   this.hInst=0;\n"
				"	this.ReadAll = function(){\n"
				"		print('testClass.ReadAll() called');\n" 	
				"	}\n"
				"}";

	//add this script fragment to the current context (used latter)
	//safe to call eval to avoid fatal panic handler on syntax error
	duk_push_string(ctx, mClass);
	if (duk_peval(ctx) != 0) {
		printf("eval failed: %s\n", duk_safe_to_string(ctx, -1));
		goto finished;
	}
	
	//register a new native function for use in JS
	duk_push_global_object(ctx);
	duk_push_c_function(ctx, nativeFunc, DUK_VARARGS);
	duk_put_prop_string(ctx, -2, "nativeFunc");
	duk_pop(ctx);  
	
	char* test = "var ts = nativeFunc('file.txt');\n"
			"print('ts=' + ts);\n"
			"print('ts.hInst = ' + ts.hInst);\n"
			"ts.ReadAll();\n"
			"ts=null;\n"
			"print('test complete');";

	//now we will run a block of JS in configured envirnoment..
	duk_push_string(ctx, test);
	if (duk_peval(ctx) != 0) {
		printf("eval failed: %s\n", duk_safe_to_string(ctx, -1));
	}
	duk_pop(ctx);

finished:
	duk_destroy_heap(ctx);

	getch();
	return 0;
}