Implement Mega Stones as {key: value} pairs (#11684)

* Implement Mega Stones as pairs {key: value}

* Fix Mega Evolution check

* Add constructor guards to Dex getters

* Update config/formats.ts

---------

Co-authored-by: Kris Johnson <11083252+KrisXV@users.noreply.github.com>

config/formats.ts

@@ -2899,7 +2899,7 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 		onValidateSet(set, format, setHas, teamHas) {
 			if (set.item) {
 				const item = this.dex.items.get(set.item);
-				if (item.megaEvolves && !(this.ruleTable.has(`+item:${item.id}`) || this.ruleTable.has(`+pokemontag:mega`))) {
+				if (item.megaStone && !(this.ruleTable.has(`+item:${item.id}`) || this.ruleTable.has(`+pokemontag:mega`))) {
 					return [`Mega Evolution is banned.`];
 				}
 				if (item.zMove && !(this.ruleTable.has(`+item:${item.id}`))) {
@@ -3678,8 +3678,8 @@ export const Formats: import('../sim/dex-formats').FormatList = [
 			}
 			const item = this.dex.items.get(set.item);
 			if (set.item && item.megaStone) {
-				const megaSpecies = this.dex.species.get(Array.isArray(item.megaStone) ? item.megaStone[0] : item.megaStone);
+				const megaSpecies = this.dex.species.get(item.megaStone[species.baseSpecies]);
-				if (item.megaEvolves?.includes(species.baseSpecies) && megaSpecies.bst > 625) {
+				if (megaSpecies.bst > 625) {
 					return [
 						`${set.name || set.species}'s item ${item.name} is banned.`, `(Pok\u00e9mon with a BST higher than 625 are banned)`,
 					];

data/mods/chatbats/items.ts

@@ -13,12 +13,10 @@ export const Items: import('../../../sim/dex-items').ModdedItemDataTable = {
 	masquerainite: {
 		name: "Masquerainite",
 		spritenum: 1,
-		megaStone: "Masquerain-Mega",
+		megaStone: { "Masquerain": "Masquerain-Mega" },
-		megaEvolves: "Masquerain",
 		itemUser: ["Masquerain"],
 		onTakeItem(item, source) {
-			if (item.megaEvolves === source.baseSpecies.baseSpecies) return false;
+			return !item.megaStone?.[source.baseSpecies.baseSpecies];
-			return true;
 		},
 		num: -1,
 		gen: 9,
@@ -59,12 +57,10 @@ export const Items: import('../../../sim/dex-items').ModdedItemDataTable = {
 	typhlosionite: {
 		name: "Typhlosionite",
 		spritenum: 1,
-		megaStone: "Typhlosion-Mega",
+		megaStone: { "Typhlosion": "Typhlosion-Mega" },
-		megaEvolves: "Typhlosion",
 		itemUser: ["Typhlosion"],
 		onTakeItem(item, source) {
-			if (item.megaEvolves === source.baseSpecies.baseSpecies) return false;
+			return !item.megaStone?.[source.baseSpecies.baseSpecies];
-			return true;
 		},
 		num: -2,
 		gen: 9,

data/mods/gen8/rulesets.ts

@@ -92,10 +92,10 @@ export const Rulesets: import('../../../sim/dex-formats').ModdedFormatDataTable
 				if (["Zacian", "Zamazenta"].includes(species.baseSpecies) && this.toID(set.item).startsWith('rusted')) {
 					species = this.dex.species.get(set.species + "-Crowned");
 				}
-				if (set.item && this.dex.items.get(set.item).megaStone) {
+				if (set.item) {
 					const item = this.dex.items.get(set.item);
-					if (item.megaEvolves === species.baseSpecies) {
+					if (item.megaStone?.[species.baseSpecies]) {
-						species = this.dex.species.get(Array.isArray(item.megaStone) ? item.megaStone[0] : item.megaStone);
+						species = this.dex.species.get(item.megaStone[species.baseSpecies]);
 					}
 				}
 				if (
@@ -123,8 +123,8 @@ export const Rulesets: import('../../../sim/dex-formats').ModdedFormatDataTable
 				}
 				if (set.item) {
 					const item = this.dex.items.get(set.item);
-					if (item.megaEvolves === set.species) {
+					if (item.megaStone?.[set.species]) {
-						godSpecies = this.dex.species.get(Array.isArray(item.megaStone) ? item.megaStone[0] : item.megaStone);
+						godSpecies = this.dex.species.get(item.megaStone[set.species]);
 					}
 					if (["Zacian", "Zamazenta"].includes(godSpecies.baseSpecies) && item.id.startsWith('rusted')) {
 						godSpecies = this.dex.species.get(set.species + "-Crowned");

data/mods/gen9legendsou/items.ts

@@ -2,15 +2,15 @@ export const Items: import('../../../sim/dex-items').ModdedItemDataTable = {
 	slowbronite: {
 		inherit: true,
 		onTakeItem(item, source) {
-			if (item.megaEvolves === source.baseSpecies.name || item.megaStone === source.baseSpecies.name) return false;
+			return !item.megaStone || (!item.megaStone[source.baseSpecies.name] &&
-			return true;
+				!Object.values(item.megaStone).includes(source.baseSpecies.name));
 		},
 	},
 	greninjite: {
 		inherit: true,
 		onTakeItem(item, source) {
-			if (item.megaEvolves === source.baseSpecies.name || item.megaStone === source.baseSpecies.name) return false;
+			return !item.megaStone || (!item.megaStone[source.baseSpecies.name] &&
-			return true;
+				!Object.values(item.megaStone).includes(source.baseSpecies.name));
 		},
 	},
 	zygardite: {

data/mods/gen9legendsou/scripts.ts

@@ -57,23 +57,8 @@ export const Scripts: ModdedBattleScriptsData = {
 				pokemon.baseMoves.includes(this.battle.toID(altForme.requiredMove)) && !item.zMove) {
 				return altForme.name;
 			}
-			if (Array.isArray(item.megaEvolves)) {
+			if (!item.megaStone) return null;
-				if (!Array.isArray(item.megaStone)) {
+			return item.megaStone[species.name];
-					throw new Error(`${item.name}#megaEvolves and ${item.name}#megaStone type mismatch`);
-				}
-				if (item.megaEvolves.length !== item.megaStone.length) {
-					throw new Error(`${item.name}#megaEvolves and ${item.name}#megaStone length mismatch`);
-				}
-				const index = item.megaEvolves.indexOf(species.name);
-				if (index < 0) return null;
-				return item.megaStone[index];
-			} else {
-				if (item.megaEvolves === species.name) {
-					if (Array.isArray(item.megaStone)) throw new Error(`${item.name}#megaEvolves and ${item.name}#megaStone type mismatch`);
-					return item.megaStone;
-				}
-			}
-			return null;
 		},
 		runMegaEvo(pokemon) {
 			const speciesid = pokemon.canMegaEvo || pokemon.canUltraBurst;

data/mods/gen9ssb/items.ts

@@ -14,11 +14,9 @@ export const Items: import('../../../sim/dex-items').ModdedItemDataTable = {
 		name: "Flygonite",
 		spritenum: 111,
 		itemUser: ["Flygon"],
-		megaEvolves: "Flygon",
+		megaStone: { "Trapinch": "Flygon" },
-		megaStone: "Trapinch",
 		onTakeItem(item, source) {
-			if (item.megaEvolves === source.baseSpecies.baseSpecies) return false;
+			return !item.megaStone?.[source.baseSpecies.baseSpecies];
-			return true;
 		},
 		desc: "If held by a Flygon, this item allows it to Mega Evolve in battle.",
 	},
@@ -36,7 +34,7 @@ export const Items: import('../../../sim/dex-items').ModdedItemDataTable = {
 	gardevoirite: {
 		inherit: true,
 		itemUser: ["Ralts"],
-		megaEvolves: "Ralts",
+		megaStone: { "Ralts": "Gardevoir-Mega" },
 		desc: "If held by a Ralts, this item allows it to Mega Evolve in battle.",
 	},
 	// Peary

data/mods/gen9ssb/scripts.ts

@@ -963,26 +963,11 @@ export const Scripts: ModdedBattleScriptsData = {
 				pokemon.baseMoves.includes(this.battle.toID(altForme.requiredMove)) && !item.zMove) {
 				return altForme.name;
 			}
+			if (!item.megaStone) return null;
 			// a hacked-in Megazard X can mega evolve into Megazard Y, but not into Megazard X
-			if (Array.isArray(item.megaEvolves)) {
+			// FIXME: Change to species.name when champions comes
-				if (!Array.isArray(item.megaStone)) {
+			const megaEvolution = item.megaStone[species.baseSpecies];
-					throw new Error(`${item.name}#megaEvolves and ${item.name}#megaStone type mismatch`);
+			return megaEvolution && megaEvolution !== species.name ? megaEvolution : null;
-				}
-				if (item.megaEvolves.length !== item.megaStone.length) {
-					throw new Error(`${item.name}#megaEvolves and ${item.name}#megaStone length mismatch`);
-				}
-				// FIXME: Change to species.name when champions comes
-				const index = item.megaEvolves.indexOf(species.baseSpecies);
-				if (index < 0) return null;
-				return item.megaStone[index];
-				// FIXME: Change to species.name when champions comes
-			} else {
-				if (item.megaEvolves === species.baseSpecies) {
-					if (Array.isArray(item.megaStone)) throw new Error(`${item.name}#megaEvolves and ${item.name}#megaStone type mismatch`);
-					return item.megaStone;
-				}
-			}
-			return null;
 		},
 
 		// 1 Z per pokemon

data/mods/mixandmega/scripts.ts

@@ -385,12 +385,8 @@ export const Scripts: ModdedBattleScriptsData = {
 			if (pokemon.species.isMega) return null;
 
 			const item = pokemon.getItem();
-			if (item.megaStone) {
+			if (!item.megaStone || item.megaStone[pokemon.baseSpecies.name]) return null;
-				if (item.megaStone.includes(pokemon.baseSpecies.name)) return null;
+			return Object.values(item.megaStone)[0];
-				return Array.isArray(item.megaStone) ? item.megaStone[0] : item.megaStone;
-			} else {
-				return null;
-			}
 		},
 		runMegaEvo(pokemon) {
 			if (pokemon.species.isMega) return false;

data/random-battles/gen7/teams.ts

@@ -1607,8 +1607,7 @@ export class RandomGen7Teams extends RandomGen8Teams {
 			if (isMonotype) {
 				// Prevents Mega Evolutions from breaking the type limits
 				if (itemData.megaStone) {
-					const megaSpecies = this.dex.species.get(Array.isArray(itemData.megaStone) ?
+					const megaSpecies = this.dex.species.get(Object.values(itemData.megaStone)[0]);
-						itemData.megaStone[0] : itemData.megaStone);
 					if (types.length > megaSpecies.types.length) types = [species.types[0]];
 					// Only check the second type because a Mega Evolution should always share the first type with its base forme.
 					if (megaSpecies.types[1] && types[1] && megaSpecies.types[1] !== types[1]) {

data/rulesets.ts

@@ -1507,17 +1507,9 @@ export const Rulesets: import('../sim/dex-formats').FormatDataTable = {
 					typeTable = typeTable.filter(type => species.types.includes(type));
 				}
 				const item = this.dex.items.get(set.item);
-				if (item.megaStone) {
+				if (item.megaStone?.[species.name]) {
-					if (Array.isArray(item.megaStone)) {
+					species = this.dex.species.get(item.megaStone[species.name]);
-						const index = (item.megaEvolves as string[]).indexOf(species.name);
+					typeTable = typeTable.filter(type => species.types.includes(type));
-						if (index >= 0) {
-							species = this.dex.species.get(item.megaStone[index]);
-							typeTable = typeTable.filter(type => species.types.includes(type));
-						}
-					} else {
-						species = this.dex.species.get(item.megaStone);
-						typeTable = typeTable.filter(type => species.types.includes(type));
-					}
 				}
 				if (item.id === "ultranecroziumz" && species.baseSpecies === "Necrozma") {
 					species = this.dex.species.get("Necrozma-Ultra");
@@ -1556,17 +1548,9 @@ export const Rulesets: import('../sim/dex-formats').FormatDataTable = {
 				}
 				color = species.color;
 				const item = this.dex.items.get(set.item);
-				if (item.megaStone) {
+				if (item.megaStone?.[species.name]) {
-					if (Array.isArray(item.megaStone)) {
+					species = this.dex.species.get(item.megaStone[species.name]);
-						const index = (item.megaEvolves as string[]).indexOf(species.name);
+					color = species.color;
-						if (index >= 0) {
-							species = this.dex.species.get(item.megaStone[index]);
-							color = species.color;
-						}
-					} else {
-						species = this.dex.species.get(item.megaStone);
-						color = species.color;
-					}
 				}
 				if (item.id === "ultranecroziumz" && species.baseSpecies === "Necrozma") {
 					species = this.dex.species.get("Necrozma-Ultra");
@@ -2666,12 +2650,10 @@ export const Rulesets: import('../sim/dex-formats').FormatDataTable = {
 				) {
 					species = this.dex.species.get(`${species.baseSpecies}-Crowned`);
 				}
-				if (set.item && this.dex.items.get(set.item).megaStone) {
+				if (set.item) {
 					const item = this.dex.items.get(set.item);
-					if (item.megaEvolves?.includes(species.name)) {
+					if (item.megaStone?.[species.name]) {
-						species = this.dex.species.get(Array.isArray(item.megaEvolves) ?
+						species = this.dex.species.get(item.megaStone[species.name]);
-							(item.megaStone as string[])[item.megaEvolves.indexOf(species.name)] :
-							item.megaStone as string);
 					}
 				}
 				if (this.ruleTable.isRestrictedSpecies(species) ||
@@ -2693,10 +2675,8 @@ export const Rulesets: import('../sim/dex-formats').FormatDataTable = {
 				}
 				if (set.item) {
 					const item = this.dex.items.get(set.item);
-					if (item.megaEvolves?.includes(set.species)) {
+					if (item.megaStone?.[set.species]) {
-						godSpecies = this.dex.species.get(Array.isArray(item.megaEvolves) ?
+						godSpecies = this.dex.species.get(item.megaStone[set.species]);
-							(item.megaStone as string[])[item.megaEvolves.indexOf(set.species)] :
-							item.megaStone as string);
 					}
 					if (["Zacian", "Zamazenta"].includes(godSpecies.baseSpecies) && item.id.startsWith('rusted')) {
 						godSpecies = this.dex.species.get(set.species + "-Crowned");

server/chat-plugins/othermetas.ts

@@ -29,14 +29,23 @@ function getMegaStone(stone: string, mod = 'gen9'): Item | null {
 				id: move.id,
 				name: move.name,
 				fullname: move.name,
-				megaEvolves: 'Rayquaza',
+				megaStone: { 'Rayquaza': 'Rayquaza-Mega' },
-				megaStone: 'Rayquaza-Mega',
 				exists: true,
 				// Adding extra values to appease typescript
 				gen: 6,
 				num: -1,
 				effectType: 'Item',
 				sourceEffect: '',
+				isBerry: false,
+				ignoreKlutz: false,
+				isGem: false,
+				isPokeball: false,
+				isPrimalOrb: false,
+				shortDesc: "",
+				desc: "",
+				isNonstandard: null,
+				noCopy: false,
+				affectsFainted: false,
 			} as Item;
 		} else {
 			return null;
@@ -131,8 +140,8 @@ export const commands: Chat.ChatCommands = {
 				megaSpecies = dex.species.get(forcedForme);
 				baseSpecies = dex.species.get(forcedForme.split('-')[0]);
 			} else {
-				megaSpecies = dex.species.get(Array.isArray(stone.megaStone) ? stone.megaStone[0] : stone.megaStone);
+				megaSpecies = dex.species.get(Object.values(stone.megaStone!)[0]);
-				baseSpecies = dex.species.get(Array.isArray(stone.megaEvolves) ? stone.megaEvolves[0] : stone.megaEvolves);
+				baseSpecies = dex.species.get(Object.keys(stone.megaStone!)[0]);
 			}
 			break;
 		}
@@ -282,8 +291,8 @@ export const commands: Chat.ChatCommands = {
 					megaSpecies = dex.species.get(forcedForme);
 					baseSpecies = dex.species.get(forcedForme.split('-')[0]);
 				} else {
-					megaSpecies = dex.species.get(Array.isArray(aStone.megaStone) ? aStone.megaStone[0] : aStone.megaStone);
+					megaSpecies = dex.species.get(Object.values(aStone.megaStone!)[0]);
-					baseSpecies = dex.species.get(Array.isArray(aStone.megaEvolves) ? aStone.megaEvolves[0] : aStone.megaEvolves);
+					baseSpecies = dex.species.get(Object.keys(aStone.megaStone!)[0]);
 				}
 				break;
 			}

server/chat-plugins/randombattles/ssb.tsx

@@ -373,7 +373,7 @@ class SSBSetsHTML extends Chat.JSX.Component<{ target: string }> {
 			<SSBInnateHTML name={setName} dex={dex} baseDex={baseDex} />
 			<SSBPokemonHTML species={set.species} dex={dex} baseDex={baseDex} />
 			{(!Array.isArray(set.item) && item.megaStone) && <SSBPokemonHTML
-				species={Array.isArray(item.megaStone) ? item.megaStone[0] : item.megaStone} dex={dex} baseDex={baseDex}
+				species={Object.values(item.megaStone)[0]} dex={dex} baseDex={baseDex}
 			/>}
 			{/* keys and Kennedy have an itemless forme change */}
 			{['Rayquaza'].includes(set.species) && <SSBPokemonHTML species={`${set.species}-Mega`} dex={dex} baseDex={baseDex} />}

server/chat-plugins/randombattles/winrates.tsx

@@ -134,7 +134,7 @@ export function getSpeciesName(set: PokemonSet, format: Format) {
 	} else if (species === "Groudon" && item.name === "Red Orb") {
 		return "Groudon-Primal";
 	} else if (item.megaStone) {
-		return Array.isArray(item.megaStone) ? item.megaStone[0] : item.megaStone;
+		return Object.values(item.megaStone)[0];
 	} else if (species === "Rayquaza" && moves.includes('Dragon Ascent') && !item.zMove && megaRayquazaPossible) {
 		return "Rayquaza-Mega";
 	} else if (species === "Poltchageist-Artisan") { // Babymons from here on out

sim/battle-actions.ts

@@ -1871,21 +1871,15 @@ export class BattleActions {
 			pokemon.baseMoves.includes(toID(altForme.requiredMove)) && !item.zMove) {
 			return altForme.name;
 		}
+		if (!item.megaStone) return null;
 		// Temporary hardcode until generation shift
-		if ((species.baseSpecies === "Floette" || species.baseSpecies === "Zygarde") && item.megaEvolves === species.name) {
+		if ((species.baseSpecies === "Floette" || species.baseSpecies === "Zygarde") && item.megaStone[species.name]) {
-			return item.megaStone as string;
+			return item.megaStone[species.name];
 		}
 		// a hacked-in Megazard X can mega evolve into Megazard Y, but not into Megazard X
-		if (Array.isArray(item.megaStone)) {
+		// FIXME: Change to species.name when champions comes
-			// FIXME: Change to species.name when champions comes
+		const megaEvolution = item.megaStone[species.baseSpecies];
-			const index = (item.megaEvolves as string[]).indexOf(species.baseSpecies);
+		return megaEvolution && megaEvolution !== species.name ? megaEvolution : null;
-			if (index < 0) return null;
-			return item.megaStone[index];
-			// FIXME: Change to species.name when champions comes
-		} else if (item.megaEvolves === species.baseSpecies && item.megaStone !== species.name) {
-			return item.megaStone;
-		}
-		return null;
 	}
 
 	canUltraBurst(pokemon: Pokemon) {

sim/dex-abilities.ts

@@ -85,7 +85,7 @@ export class DexAbilities {
 	}
 
 	getByID(id: ID): Ability {
-		if (id === '') return EMPTY_ABILITY;
+		if (id === '' || id === 'constructor') return EMPTY_ABILITY;
 		let ability = this.abilityCache.get(id);
 		if (ability) return ability;
 

sim/dex-conditions.ts

@@ -665,7 +665,7 @@ export class DexConditions {
 	}
 
 	getByID(id: ID): Condition {
-		if (id === '') return EMPTY_CONDITION;
+		if (id === '' || id === 'constructor') return EMPTY_CONDITION;
 
 		let condition = this.conditionCache.get(id);
 		if (condition) return condition;

sim/dex-data.ts

@@ -172,7 +172,7 @@ export class DexNatures {
 		return this.getByID(toID(name));
 	}
 	getByID(id: ID): Nature {
-		if (id === '') return EMPTY_NATURE;
+		if (id === '' || id === 'constructor') return EMPTY_NATURE;
 		let nature = this.natureCache.get(id);
 		if (nature) return nature;
 
@@ -293,7 +293,7 @@ export class DexTypes {
 	}
 
 	getByID(id: ID): TypeInfo {
-		if (id === '') return EMPTY_TYPE_INFO;
+		if (id === '' || id === 'constructor') return EMPTY_TYPE_INFO;
 		let type = this.typeCache.get(id);
 		if (type) return type;
 

sim/dex-items.ts

@@ -43,17 +43,11 @@ export class Item extends BasicEffect implements Readonly<BasicEffect> {
 	 */
 	readonly onMemory?: string;
 	/**
-	 * If this is a mega stone: The name (e.g. Charizard-Mega-X) of the
+	 * If this is a mega stone: A pair (e.g. Charizard: Charizard-Mega-X) of the
-	 * forme this allows transformation into.
+	 * forme this allows transformation from and into.
 	 * undefined, if not a mega stone.
 	 */
-	readonly megaStone?: string | string[];
+	readonly megaStone?: { [megaEvolves: string]: string };
-	/**
-	 * If this is a mega stone: The name (e.g. Charizard) of the
-	 * forme this allows transformation from.
-	 * undefined, if not a mega stone.
-	 */
-	readonly megaEvolves?: string | string[];
 	/**
 	 * If this is a Z crystal: true if the Z Crystal is generic
 	 * (e.g. Firium Z). If species-specific, the name
@@ -116,7 +110,6 @@ export class Item extends BasicEffect implements Readonly<BasicEffect> {
 		this.onDrive = data.onDrive || undefined;
 		this.onMemory = data.onMemory || undefined;
 		this.megaStone = data.megaStone || undefined;
-		this.megaEvolves = data.megaEvolves || undefined;
 		this.zMove = data.zMove || undefined;
 		this.zMoveType = data.zMoveType || undefined;
 		this.zMoveFrom = data.zMoveFrom || undefined;
@@ -176,7 +169,7 @@ export class DexItems {
 	}
 
 	getByID(id: ID): Item {
-		if (id === '') return EMPTY_ITEM;
+		if (id === '' || id === 'constructor') return EMPTY_ITEM;
 		let item = this.itemCache.get(id);
 		if (item) return item;
 		if (this.dex.getAlias(id)) {

sim/dex-moves.ts

@@ -621,7 +621,7 @@ export class DexMoves {
 	}
 
 	getByID(id: ID): Move {
-		if (id === '') return EMPTY_MOVE;
+		if (id === '' || id === 'constructor') return EMPTY_MOVE;
 		let move = this.moveCache.get(id);
 		if (move) return move;
 		if (this.dex.getAlias(id)) {

sim/dex-species.ts

@@ -436,7 +436,7 @@ export class DexSpecies {
 	}
 
 	getByID(id: ID): Species {
-		if (id === '') return EMPTY_SPECIES;
+		if (id === '' || id === 'constructor') return EMPTY_SPECIES;
 		let species: Mutable<Species> | undefined = this.speciesCache.get(id);
 		if (species) return species;
 

sim/team-validator.ts

@@ -526,14 +526,8 @@ export class TeamValidator {
 
 		if (ruleTable.has('obtainableformes')) {
 			const canMegaEvo = dex.gen <= 7 || ruleTable.has('+pokemontag:past');
-			if (item.megaEvolves?.includes(species.name)) {
+			if (item.megaStone?.[species.name]) {
-				if (!item.megaStone) throw new Error(`Item ${item.name} has no base form for mega evolution`);
+				tierSpecies = dex.species.get(item.megaStone[species.name]);
-				if (Array.isArray(item.megaEvolves)) {
-					const idx = item.megaEvolves.indexOf(species.name);
-					tierSpecies = dex.species.get(item.megaStone[idx]);
-				} else {
-					tierSpecies = dex.species.get(item.megaStone as string);
-				}
 			} else if (item.id === 'redorb' && species.id === 'groudon') {
 				tierSpecies = dex.species.get('Groudon-Primal');
 			} else if (item.id === 'blueorb' && species.id === 'kyogre') {

sim/tools/exhaustive-runner.ts

@@ -137,8 +137,8 @@ export class ExhaustiveRunner {
 		const signatures = new Map();
 		for (const id of pools.items.possible) {
 			const item = dex.data.Items[id];
-			if (item.megaEvolves) {
+			if (item.megaStone) {
-				const pokemon = toID(item.megaEvolves);
+				const pokemon = toID(Object.keys(item.megaStone)[0]);
 				const combo = { item: id };
 				let combos = signatures.get(pokemon);
 				if (!combos) {

test/sim/data.js

@@ -132,12 +132,6 @@ describe('Dex data', () => {
 			const entry = Items[itemid];
 			assert.equal(toID(entry.name), itemid, `Mismatched Item key "${itemid}" of "${entry.name}"`);
 			assert.equal(typeof entry.num, 'number', `Item ${entry.name} should have a number`);
-			if (entry.megaStone) {
-				assert.equal(typeof entry.megaStone, typeof entry.megaEvolves, `Item ${entry.name} megaStone and megaEvolves should both be the same type`);
-				if (Array.isArray(entry.megaStone)) {
-					assert.equal(entry.megaStone.length, entry.megaEvolves.length, `Item ${entry.name} megaStone and megaEvolves arrays should be the same length`);
-				}
-			}
 		}
 	});
 

tools/set-import/importer.ts

@@ -312,7 +312,8 @@ function skip(dex: ModdedDex, format: Format, pokemon: string, set: DeepPartial<
 		if (pokemon === 'Rayquaza-Mega') {
 			return format.id.includes('ubers') || !hasMove('Dragon Ascent');
 		} else {
-			return dex.items.get(set.item).megaStone !== pokemon;
+			const item = dex.items.get(set.item);
+			return !item.megaStone || !Object.values(item.megaStone).includes(pokemon);
 		}
 	}
 	if (pokemon === 'Necrozma-Ultra' && set.item !== 'Ultranecrozium Z') return true;