やったん

was/were

→ だ
phrase Rare #35,180
was/were Casual Kansai-style form of やった with explanatory ん, often followed by particles such as や, か, or よ.
JA: 昨日は休みやったんよ。
EN: Yesterday was a day off.

それでお前元気やったんか

So, were you doing okay?

— 火垂るの墓 (1988)

まあまあ無事やったんやし

Well, at least you made it through okay.

— すずめの戸締まり (2022)

あんたの電話がイヤやったんやろ

They must not have liked your call, huh?

— 君の名は。 (2016)

昨日のお客さん⸺めっちゃイケメンやったんよ

That customer yesterday was super handsome.

— すずめの戸締まり (2022)

今日が最後やったんや

Today was the last day.

— PERFECT BLUE (1998)