minecraft-assets/data/minecraft/recipe/purple_dye.json

{
  "type": "minecraft:crafting_shapeless",
  "category": "misc",
  "ingredients": [
    "minecraft:blue_dye",
    "minecraft:red_dye"
  ],
  "result": {
    "count": 2,
    "id": "minecraft:purple_dye"
  }
}