A casual interjection meaning 'okay' or 'sure' used to show agreement or understanding (similar to 'はい' or 'あいよ').
「この箱、持って」「はいよ、任せて。」
"Can you carry this box?" "Sure, leave it to me."
店員が品物を渡すときに『はいよ』と言って笑った。
The clerk smiled and said 'haiyo' while handing over the item.
あいよ、すぐ戻るから待っててね。
Okay, I'll be right back, so wait for me.