Class PlayerInventoryItemChangeAfterEvent

Example: inventoryChangeListener.ts

import {
    world,
    PlayerInventoryItemChangeAfterEvent,
    InventoryItemEventOptions,
    PlayerInventoryType,
} from "@minecraft/server";

// Example of handling player inventory item change events
function setupInventoryChangeListener() {
    // Basic event subscription - monitor all inventory changes
    world.afterEvents.playerInventoryItemChange.subscribe((event: PlayerInventoryItemChangeAfterEvent) => {
        console.log(`${event.player.name} inventory changed:`);
        console.log(`Slot: ${event.slot} in ${event.inventoryType}`);

        if (event.beforeItemStack) {
            console.log(`Previous item: ${event.beforeItemStack.typeId} (${event.beforeItemStack.amount})`);
        } else {
            console.log("Previous: empty slot");
        }

        if (event.itemStack) {
            console.log(`New item: ${event.itemStack.typeId} (${event.itemStack.amount})`);
        } else {
            console.log("New: empty slot");
        }
    });

    // Subscription with filtering options - monitor specific inventory types and items
    const inventoryOptions: InventoryItemEventOptions = {
        inventoryType: PlayerInventoryType.Hotbar,
        includeItems: ["minecraft:diamond_sword", "minecraft:bow", "minecraft:shield"],
        excludeItems: ["minecraft:dirt", "minecraft:cobblestone"],
        includeTags: ["minecraft:weapons", "minecraft:tools"],
        excludeTags: ["minecraft:building_blocks"],
        ignoreQuantityChange: false, // Track quantity changes
        allowedSlots: [0, 1, 2, 3, 4], // Only monitor first 5 hotbar slots
    };

    world.afterEvents.playerInventoryItemChange.subscribe((event: PlayerInventoryItemChangeAfterEvent) => {
        console.log(`Important inventory change detected!`);
        console.log(`Player: ${event.player.name}`);
        console.log(`Slot ${event.slot} in ${event.inventoryType}`);

        // Check for specific item types
        if (event.itemStack?.typeId === "minecraft:diamond_sword") {
            console.log("Player equipped a diamond sword!");
        } else if (event.itemStack?.typeId === "minecraft:bow") {
            console.log("Player equipped a bow!");
        }

        // Check for item removal
        if (event.beforeItemStack && !event.itemStack) {
            console.log(`Player removed ${event.beforeItemStack.typeId} from slot ${event.slot}`);
        }

        // Check for quantity changes
        if (event.beforeItemStack && event.itemStack && event.beforeItemStack.typeId === event.itemStack.typeId) {
            const quantityChange = event.itemStack.amount - event.beforeItemStack.amount;
            if (quantityChange > 0) {
                console.log(`Player gained ${quantityChange} of ${event.itemStack.typeId}`);
            } else if (quantityChange < 0) {
                console.log(`Player lost ${Math.abs(quantityChange)} of ${event.itemStack.typeId}`);
            }
        }
    }, inventoryOptions);

    // Example: Monitor only hotbar changes
    const hotbarOnlyOptions: InventoryItemEventOptions = {
        inventoryType: PlayerInventoryType.Hotbar,
    };

    world.afterEvents.playerInventoryItemChange.subscribe((event: PlayerInventoryItemChangeAfterEvent) => {
        console.log(`Hotbar change: Player ${event.player.name} slot ${event.slot}`);
    }, hotbarOnlyOptions);
}

// Call this function to set up the event listeners
setupInventoryChangeListener();
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