Why is my advancement not registering?

I'm trying to make an advancement that rewards the player with a function when they eat an apple, but after putting the text below in pack/advancement/food/apple.json (made with the help of misode.github.io) it refuses to even show up in the advancement registry. That means it's malformed in some way, but I can't for the life of me figure out what I've done wrong here. It might change something that there's one of these for each food item, but I'm not sure. json { "criteria": { "eat": { "trigger": "minecraft:consume_item", "conditions": { "item": { "items": "minecraft:apple" } } } }, "requirements": [], "rewards": { "function": "pack:food/apple" } }