04-get-full-data.js

/* UTILS */

const getFullName = (firstName, lastName, middleName) =>
  [firstName, middleName, lastName].filter((n) => !!n).join(" ");

const getFormattedBalance = (locale, currency, value) => {
  return new Intl.NumberFormat(locale, {
    style: "currency",
    currency
  }).format(value);
};

/* PROXY */

const handleFullGet = (obj, prop) => {
  if (prop === "fullName") {
    return getFullName(
      Reflect.get(obj, "firstName"),
      Reflect.get(obj, "lastName"),
      Reflect.get(obj, "middleName")
    );
  }

  if (prop === "balance") {
    return getFormattedBalance(
      Reflect.get(obj, "locale"),
      Reflect.get(obj, "currency"),
      Reflect.get(obj, "balance")
    );
  }

  if (!(prop in obj)) {
    console.error(`${prop.toString()} doesn't exist in object`, obj);
    return;
  }

  return Reflect.get(obj, prop);
};


const createUserDataProxy = (user) => {
  const proxy = new Proxy(user, {
    get: handleFullGet
  });

  return proxy;
};

/* USE */

const user = createUserDataProxy({
  firstName: "John",
  middleName: "",
  lastName: "Doe",
  email: "john.doe@email.com",
  balance: 2649.53,
  currency: "USD",
  locale: "en-US"
});

console.log(user.fullName); // John Doe
console.log(user.balance); // $2,649.53