calculator closure

calculator.js

function calculator(operator) {

  function func(a, b) {
    return eval([a, operator, b].join(''));
  };

  return func;
}

var multiply = calculator('*');
var subtract = calculator('-');
var add = calculator('+');
var divide = calculator('/');
alert(multiply(2, 3));
alert(subtract(2, 3));
alert(add(2, 3));
alert(divide(2, 3));