Registering Pokémon weaknesses

Question

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?

Answer 1

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) -> 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)
}

Answer 2

I can't test this right now, but something like this might work, I am assuming each type in pokemonTypeDefenseChart is an array, so I combine the arrays , then loop through it once. Normally I would filter out dups, but you can't add functions, so I check if the name does not exist, and append if it doesn't

for object in objects {
    if let name = object["name"] {
        let defense = (
            (object["type"].flatMap({pokemonTypeDefenseChart[$0]}) ?? []) + 
            (object["typeTwo"].flatMap {pokemonTypeDefenseChart[$0]} ?? []))

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

}

Thanks to @TimVermeulen for cleaning up some parts of the answer