Consider javascript already support for default parameters, so maybe we can use the default parameter to specify the strong type.

[罗勇刚(Yonggang Luo)]

For example:

function addWithType(a = int64(0), b = int64(0)) {
   return a + b;
}

This function is input add two int64 and return a int64

-- 
         此致
礼
罗勇刚
Yours
    sincerely,
Yonggang Luo