A little command line program that simulates a vending machine.
"Admin" User can stock the machine with snacks, and load coins into it.
A user can pay coins into the machine, and select a product.
Once the user has enough balance for the selected product, it's dispensed from the machine, and the user receives their change.

##Install Prerequisites: node + npm
run npm install ##Tests run npm test ##Run run npm run
type in the ? command to see how to use the command-line interface.

• Note: all values are in pence (i.e price = 50 means 50p)

#About The main logic is the Dispenser object, which holds the current state of chosen snack and balance, receives snack choices and payments, and dispenses a snack when balance is sufficient.
It uses the SnacksRepository to check and update availability of snacks, and ChangeCalculator to return the correct change.
If a change cannot be given, an error occurs.

I feel that this is a nice and decoupled design, which allows for different parts (for example - the way change is calculated) to be modified independently. ##Things to improve Obviously this is just a little program whipped up in a few hours. There are quite a few things that can be improved:

• The algorithm for change calculation, which is very dumb.
• The design of ChangeCalculaor should be different; it should be split between data storage and change logic. A new CoinsRepository should be introduced to handle adding and removing coins.
• It's possibel to make Dispenser a little more single-responsible by separating _dispenseIfPossible to a method that handles dispensing, and another method which handles returning the remaining amount to pay / change.
• Return value from Dispenser.pay can be either a number, indicating the amount due, or an object, indicating the change given. This is a bit inconsistent.
• In a 'real world' scenario, the repositories would be asynchronous, so we'd need to make the using code asynch as well.
• It would be nice to allow restocking snacks and loading coins from files.
• Better output formatting would be nice.