Set type for function parameters?

Question

Is there a way to let a javascript function know that a certain parameter is of a certain type?

Being able to do something like this would be perfect:

Answer 1

I've been thinking about this too. From a C background, you can simulate function return code types, as well as, parameter types, using something like the following:

function top_function() {
    var rc;
    console.log("1st call");
    rc = Number(test_function("number", 1, "string", "my string"));
    console.log("typeof rc: " + typeof rc + "   rc: " + rc);
    console.log("2nd call");
    rc = Number(test_function("number", "a", "string", "my string"));
    console.log("typeof rc: " + typeof rc + "   rc: " + rc);
}
function test_function(parm_type_1, parm_val_1, parm_type_2, parm_val_2) {
    if (typeof parm_val_1 !== parm_type_1) console.log("Parm 1 not correct type");
    if (typeof parm_val_2 !== parm_type_2) console.log("Parm 2 not correct type");
    return parm_val_1;
}

The Number before the calling function returns a Number type regardless of the type of the actual value returned, as seen in the 2nd call where typeof rc = number but the value is NaN

the console.log for the above is:

1st call
typeof rc: number   rc: 1
2nd call
Parm 1 not correct type
typeof rc: number   rc: NaN