iteration over a typescript map failing

I'm using the function below to compare two maps. What's interesting is that the code inside for loop is never executed. So, console.log(key,val) code is never executed. Of course I made sure that the maps I'm comparing are not empty and are of same size to force execution of the code inside the for loop. Am I making a really silly mistake or am missing a deep concept?

private compareMaps(map1, map2) {
        var testVal;
        if (!(map1 && map2)) {
            return false;
        }
        if (map1.size !== map2.size) {
            return false;
        }
        for (var [key, val] of map1) {
            testVal = map2.get(key);
            console.log(key, val);
            if (testVal !== val || (testVal === undefined && !map2.has(key))) {
                return false;
            }
        }
        return true;
    }