Registering Pokémon weaknesses I recently answered a question that had me wondering if I could simplify this below code without creating an extra function:

for object in objects {
    if let type = object["type"] where !type.isEmpty, let name = object["name"] {

        print(pokemonTypeDefenseChart[type])
        for weakness in pokemonTypeDefenseChart[type]! {
            if pokemonWeaknessChart[weakness] == nil {
                pokemonWeaknessChart[weakness] = []
            }
            pokemonWeaknessChart[weakness]?.append(name)
        }
    }

    if let typeTwo = object["typeTwo"] where !typeTwo.isEmpty, let name = object["name"] {
        for weakness in pokemonTypeDefenseChart[typeTwo]! {
            if pokemonWeaknessChart[weakness] == nil {
                pokemonWeaknessChart[weakness] = []
            }
            pokemonWeaknessChart[weakness]?.append(name)
        }
    }
}


Essentially the code loops through objects (list of pokemon) and is designed to add all of the pokemon weak to type (and optionally typeTwo).

I ended up just refactoring the for statements inside the if let statements into a function, but I was wondering if it was possible to compress these without an extra function. The only difference is the type.

I know I could simplify it a bit by using a map instead of for loops but I wanted to keep it more understandable for the question.

Any ideas?
You could do something like:

for x in ["type", "typeTwo"] {
    if let type = object[x] where !type.isEmpty,
        let name = object["name"],
        defenseChart = pokemonTypeDefenseChart[type] { /* ... */ }
}


Also, to simplify the rest of your code, you could extend Dictionary like this:

extension Dictionary {
    subscript(key: Key, fallback fallback: Value) -&gt; Value {
        get { return self[key] ?? fallback }
        set { self[key] = newValue }
    }
}


This allows you to replace this:

for weakness in defenseChart {
    if pokemonWeaknessChart[weakness] == nil {
        pokemonWeaknessChart[weakness] = []
    }
    pokemonWeaknessChart[weakness]?.append(name)
}


by this:

for weakness in defenseChart {
    pokemonWeaknessChart[weakness, fallback: []].append(name)
}