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1 | +++ a/README.md | ||
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1 | +# ChangeDispenserController Class | ||
2 | + | ||
3 | +#### calculateChange(unitsTendered, price) | ||
4 | + | ||
5 | +**unitsTendered:** An array of instances of some kind of MonetaryUnit subclass. You can assert that the units tendered all have the same currency and that the amount tendered is greater than price. | ||
6 | +**price:** Number. You can assert that the units tendered match the currency for price, which is why price is just a number. | ||
7 | + | ||
8 | +**Returns** true if change can succesfully be dispensed, otherwise returns false to issue a refund and cancel the product. | ||
9 | + | ||
10 | +# ChangeDispenser Class | ||
11 | +An instance of ChangeDispenser is programmed to physically know what change it has to dispense and physically how to dispense it. Assume that ChangeDispenser is a thin JavaScript layer over native code. | ||
12 | + | ||
13 | +### Properties | ||
14 | +For every currency unit available, the JavaScript layer dynamically defines properties that match the class name of the monetary units using Object.defineProperty. It defines the properties as read-only properties using getter methods that return new arrays. | ||
15 | +The new arrays returned from these properties are not referenced internally. For example, `var availablePennies = someChangeDispenserInstance.UnitedStatesPennyUnit;` would give you an array containing instances of UnitedStatesPennyUnit. | ||
16 | + | ||
17 | +### Methods | ||
18 | +#### unitsAvailable(currency) | ||
19 | +Describes the types of monetary units available to dispense. | ||
20 | + | ||
21 | +**currency:** A String value for the currency, i.e. "USD". | ||
22 | + | ||
23 | +**Returns** an array of objects describing the availablity of monetary units that match the curreny passed in, sorted in descending monetaryValue: | ||
24 | +[ | ||
25 | + { | ||
26 | + propertyName: String (i.e. "UnitedStatesPennyUnit"), | ||
27 | + unitInfo: { | ||
28 | + monetaryValue: Number, | ||
29 | + currency: String, | ||
30 | + currencySymbol: String | ||
31 | + } | ||
32 | + } | ||
33 | +] | ||
34 | + | ||
35 | +#### dispense(units) | ||
36 | +Physically dispenses change for all of the monetary unit instances that you pass in. | ||
37 | + | ||
38 | +**units:** An array of instances of some kind of MonetaryUnit subclass. | ||
39 | + | ||
40 | +**Throws** an error synchronously if any instance does not exist in its Column Properties. | ||
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