LTW3/data/minecraft/loot_tables/blocks/composter.json

{
  "type": "minecraft:block",
  "pools": [
    {
      "rolls": 1.0,
      "bonus_rolls": 0.0,
      "entries": [
        {
          "type": "minecraft:item",
          "functions": [
            {
              "function": "minecraft:explosion_decay"
            }
          ],
          "name": "minecraft:composter"
        }
      ]
    },
    {
      "rolls": 1.0,
      "bonus_rolls": 0.0,
      "entries": [
        {
          "type": "minecraft:item",
          "name": "minecraft:bone_meal"
        }
      ],
      "conditions": [
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:composter",
          "properties": {
            "level": "8"
          }
        }
      ]
    }
  ]
}