Comparing methods to computed properties

With computed properties, you saw in the last chapter that you could run code from inside a structure. That sounds a lot like a method. What’s the difference? It really comes down to a matter of style, but there are a few helpful thoughts to help you decide. Properties hold values that you can get and set, while methods perform work. Sometimes this distinction gets fuzzy when a method’s sole purpose is to return a single value.

Ask yourself whether you want to be able to set a value as well as get the value. A computed property can have a setter component inside to write values. Another question to consider is whether the calculation requires extensive computation or reads from a database. Even for a simple value, a method helps you indicate to future developers that the call is expensive in time and computational resources. If the call is cheap, stick with a computed property.