ecmascript 6 - typesafe rest parameter in ES6 -

do have way make rest parameter typesafe. trying following code throwing error,

<script>         function addn(name, ...numarray:number[]){         let result = 0;         numarray.foreach((n) => result += n);         return result;       }       document.write(addn('abc', 2,33,6));      </script>