Inventory System

This example shows a simple inventory system using Reheaven.

The inventory stores items, selected item, and equipped item.

Key Point

Inventory state keeps track of what the player owns, selects, and equips.

Inventory State

InventoryState.lua

local computed = Reheaven.computed

local inventory, setInventory = Reheaven.signal({
    items = {};
    selectedItem = nil;
    equippedItem = nil;
})

local itemCount = computed(function()
    return #inventory().items
end)

local hasEquippedItem = computed(function()
    return inventory().equippedItem ~= nil
end)

Inventory Actions

InventoryActions.lua

local function addItem(itemName)
    local current = inventory()
    local nextState = table.clone(current)

    nextState.items = table.clone(current.items)
    -- double clone because items is a nested table.
    -- this is where a deepClone helper can be useful :3
    table.insert(nextState.items, itemName)

    setInventory(nextState)
end

local function selectItem(itemName)
    local current = inventory()
    local nextState = table.clone(current)

    nextState.selectedItem = itemName

    setInventory(nextState)
end

local function equipSelectedItem()
    local current = inventory()

    if not current.selectedItem then
        return
    end

    local nextState = table.clone(current)

    nextState.equippedItem = current.selectedItem

    setInventory(nextState)
end

Inventory UI

InventoryUI.lua

local effect = Reheaven.effect

effect(function()
    itemCountLabel.Text = `Items: {itemCount()}`
end)

effect(function()
    local state = inventory()

    selectedLabel.Text = state.selectedItem or "None"
    equippedLabel.Text = state.equippedItem or "None"
end)

Button Input

InventoryButtons.lua

swordButton.MouseButton1Click:Connect(function()
    selectItem("Sword")
end)

equipButton.MouseButton1Click:Connect(function()
    equipSelectedItem()
end)

Inventory Flow

Item added
↓
Inventory state changes
↓
Selected or equipped item changes
↓
UI reacts

Table State

Because inventory is stored as a table signal, the examples clone the table before making changes.

Nested tables like items should also be cloned before changing them.