Envoy in Javascript - Function as Object

funcAsObject.js

var balance = 0;
var withdraw = function (amount){
  if(balance >= amount){
    balance = balance - amount;
  } else {
    throw new Error('Insufficient funds')
  }
}

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

var accrueInterest = function (interestRate) {
  balance = balance * (100 + interestRate);
}