Fun solution for a task on Codewars. https://www.codewars.com/kata/525f3eda17c7cd9f9e000b39

calc.js

var numbers = [
  "zero",
  "one",
  "two",
  "three",
  "four",
  "five",
  "six",
  "seven",
  "eight",
  "nine",
];
var operations = [
  {
    name: "plus",
    action: "+",
  },
  { name: "minus", action: "-" },
  { name: "times", action: "*" },
  { name: "dividedBy", action: "/" },
];
var that = typeof window === "undefined" ? this : window;

numbers.forEach(function (name, index) {
  that[name] = function (action) {
    return action ? eval("Math.round(" + index + action + ")") : index;
  };
});

operations.forEach(function (operation) {
  that[operation.name] = function (right) {
    return operation.action + right;
  };
});

console.log(one(plus(one())));
console.log(eight(dividedBy(three())));
console.log(seven(times(five())));
console.log(four(plus(nine())));