portal_to_alfheim.js

const ItemEntity = Java.loadClass("net.minecraft.world.entity.item.ItemEntity");

global.recipes = global.recipes || {};
/** @type {[ingredient: $Ingredient_, result: $ItemStack_][]} */
global.recipes["portal_to_alfheim"] = [
  ["#c:raw_materials/gold", "2x minecraft:gold_ingot"],
  ["#c:raw_materials/iron", "2x minecraft:iron_ingot"],
  ["#c:raw_materials/copper", "2x minecraft:copper_ingot"],
  ["nether_star", "nether_star"],
];

global.functions = global.functions || {};
/** @param {$Entity_} entity @returns {$SHOULDTP_} */
global.functions["portal_to_alfheim"] = (entity) => {
  if (entity instanceof ItemEntity) {
    let { item } = entity;
    for (let [ingredient, output] of global.recipes["portal_to_alfheim"]) {
      if (Ingredient.of(ingredient).test(item)) {
        let outputStack = Item.of(output);
        entity.item = outputStack.withCount(item.count * outputStack.count);
        break;
      }
    }
  }
  return ShouldTP.CANCEL;
};

PortalEvents.register((event) => {
  event
    .create()
    .frameBlock("minecraft:cherry_log")
    .lightWithWater()
    .tint(Color.LIME_DYE.rgb)
    .beforeTeleportation((entity) => global.functions["portal_to_alfheim"](entity));
});