Revise type damage in battle?

[LAMaglan]

It adds effects of all attacker types on all defender types. Need to check if this is "unfair" when multiple defender types are weak to one (or more) of attacker types. Additionally, maybe have rule where type advantages don't "stack" (I.e. only pick the "best" for attacker or "best" for defender. Need to check how it works in mainline games).

[LAMaglan]

It seems like type advantages do indeed "stack", i.e.if an attack is good against seveal types that the defender has, then the advantages stack: https://www.quora.com/In-Pokemon-how-is-weakness-calculated-for-dual-type-Pokemon-such-as-a-rock-ghost-type-when-hit-with-a-fighting-attack-Is-the-attack-still-negated-due-to-the-ghost-typing-or-does-the-Pokemon-still-take-double-damage

However, need to double check when an attack has no effect on one type, when the defender has that type and a type that should be weak against the attack

[LAMaglan]

Have now double checked that even if there is a type advantage (2.0), if the defender has a type that the attacker does no damage to, then no damage is done (correct)