04. Command Processor

function result() {
  let privateString = '';

  return {
    append(str) {
      privateString += str;
    },

    removeStart(n) {
      privateString = privateString.slice(n);
    },

    removeEnd(n) {
      privateString = privateString.slice(0, -n);
    },

    print() {
      return console.log(privateString);
    },
  };
}