Exporting

To export a value, append its declaration with the export keyword:

// account.js file
let balance = 0;
export const INTEREST_RATE = 0.2;

export function deposit(amount) {
  balance += amount;
}

export function withdraw(amount) {
  balance -= amount;
}

export function getBalance() {
  return balance;
}

You can export values one by one (as it is done above), or you can export all in a single statement at the end of the module:

// account.js file
let balance = 0;
const INTEREST_RATE = 0.2;

function deposit(amount) {
  balance += amount;
}

function withdraw(amount) {
  balance -= amount;
}

function getBalance() {
  return balance;
}

export { INTEREST_RATE, deposit, withdraw, getBalance };

You can also give an alias to an exported value with the as keyword:

export { INTEREST_RATE as interest, deposit, withdraw, getBalance };

Moreover, you can break a long export statement into several export statements (not a very common practice):

export { INTEREST_RATE as interest };
export { deposit, withdraw, getBalance };