I added JS support to my q3 based game.
I working with qvm<->js interaction, like syscalls in engine<->qvm

My game is opensandbox btw, almost gplv2

#define MAX_JS_ARGS 16
#define MAX_JS_STRINGSIZE 1024

typedef enum {
JS_TYPE_NONE,
JS_TYPE_INT,
JS_TYPE_FLOAT,
JS_TYPE_BOOL,
JS_TYPE_STRING
} js_type_t;

typedef union {
int int_val;
float float_val;
qboolean bool_val;
char string_val[MAX_JS_STRINGSIZE];
} js_value_t;

typedef struct {
js_type_t type[MAX_JS_ARGS];
js_value_t value[MAX_JS_ARGS];
} js_args_t;

typedef struct {
js_type_t type;
js_value_t value;
} js_result_t;

void JS_Init(void);
qboolean JSOpenFile(const char filename);
qboolean JSEval(const char code, qboolean doPrint, qboolean doResult, js_result_t result);
qboolean JSCall(int func_id, js_result_t result, js_args_t* args);