js-the-best-practice (nodeschool)

app.js

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

vendingMachine.insertCoin('q');
vendingMachine.insertCoin('q');
vendingMachine.insertCoin('q');
vendingMachine.insertCoin('q');
console.log("Insert 100");
console.log("Get product: ", vendingMachine.vendProduct('A1'));
console.log("Release: ", vendingMachine.releaseChange());

balanceManager.js

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

var balance = 0;

module.exports = {
  decreaseBalance: function (amount) {
    if (!this.canAfford(amount)) {
      throw new Error("Insufficient balance");
    }
    balance -= amount;
  },

  getBalance: function () {
    return balance;
  },

  increaseBalance: function (amount) {
    balance += amount;
  },

  canAfford: function (amount) {
    if (!this.isValidAmount(amount)) {
      throw new Error("Invalid Input");;
    }
    return amount <= balance;
  },

  isValidAmount: function (amount) {
    if (amount === null) {
      return false;
    } else {
      return true;
    }
  }
};

changeHandler.js

var products = [{
  name: 'Skittles',
  price: 85,
  id: 'A1'
}];

module.exports = {
  getProducts: function () {
    return products;
  },

  getProduct: function (productId) {
    var product = products.find(function (p) {
      return p.id === productId;
    });
    return product;
  }
};

productInventory.js

var products = [{
  name: 'Skittles',
  price: 85,
  id: 'A1'
}];

module.exports = {
  getProducts: function () {
    return products;
  },

  getProduct: function (productId) {
    var product = products.find(function (p) {
      return p.id === productId;
    });
    return product;
  }
};

vendingMachine.js

var balanceManager = require('./balanceManager');
var changeHandler = require('./changeHandler');
var productInventory = require('./productInventory');

module.exports = {
  insertCoin: function (coinType) {
    var value = changeHandler.getAmount(coinType);
    balanceManager.increaseBalance(value);
  },

  vendProduct: function (productId) {
    var product = productInventory.getProduct(productId);
    balanceManager.decreaseBalance(product.price);
    return product;
  },

  releaseChange: function () {
    var currentBalance = balanceManager.getBalance();
    balanceManager.decreaseBalance(currentBalance);
    return changeHandler.convertToChange(currentBalance);
  }
};