OO Javascript Example

BankAcct.js

var BankAcct = (function() {
  // The BankAcct function will execute when it is new'ed,
  // so this.name and this.balance will be set
  function BankAcct(name) {
    this.name = name;
    this.balance = 100; // starting money
  }
  
  // These functions will be available on any new BankAcct() objects
  BankAcct.prototype.changeName = function(newName) {
    this.name = newName;
  };
  
  BankAcct.prototype.spend = function(amount) {
    if((this.balance - amount) <= 0) {
      console.log('You are out of money :(');
    } else {
      this.balance -= amount;
      console.log('You have $' + this.balance.toFixed(2) + ' in your bank account');
    }
  };
  
  return BankAcct;
})();

module.exports = BankAcct;

test.js

var BankAcct = require('./BankAcct');

var accountOne = new BankAccount("Test Account"),
    accountTwo = new BankAccount("Vacation Fund");

console.log(accountOne.balance); // $100
console.log(accountTwo.balance); // $100

accountOne.changeName("Retirement");
console.log(accountOne.name); // "Retirement"
accountOne.spend(99);
console.log(accountOne.balance); // $1

accountTwo.spend(50);
console.log(accountTwo.balance); // $50