minecraft-assets/data/minecraft/recipes/red_bed_from_magenta_bed.json

{
  "type": "minecraft:crafting_shapeless",
  "category": "building",
  "group": "red_bed",
  "ingredients": [
    {
      "item": "minecraft:red_dye"
    },
    {
      "item": "minecraft:magenta_bed"
    }
  ],
  "result": {
    "item": "minecraft:red_bed"
  }
}