3. Replace src/main.luau

complete asynchronous storage lifecycle

Pending request IDs distinguish save and load completions that may arrive out of order.

Focused example

--!strict

local Host = require("luastra/host")
local State = require("luastra/state")
local UI = require("luastra/ui")

local App = require("luastra/app")
local Root = {}
local count = 0
local message = "Nothing saved yet"
local pending: { [number]: string } = {}

local function track(id: number, operation: string)
    pending[id] = operation
end

function Root.restore(payload: string): boolean
    local decoded = State.decode(payload, 1)
    if not decoded.success then return false end
    local restored = tonumber(decoded.fields.count)
    if restored == nil or restored < 0 or restored % 1 ~= 0 then return false end
    count = restored
    return true
end

function Root.render(): UI.Node
    return UI.Screen {
        id = "storage-recipe",
        UI.Text { id = "counter/title", text = "Persistent counter", variant = "title" },
        UI.Text { id = "counter/value", text = tostring(count), role = "status" },
        UI.Text { id = "counter/message", text = message, role = "status" },
        UI.Actions {
            id = "counter/actions",
            UI.Button { id = "counter/add", text = "Add", onTap = "counter.add" },
            UI.Button { id = "counter/save", text = "Save", onTap = "counter.save" },
            UI.Button { id = "counter/load", text = "Load", onTap = "counter.load" },
        },
    }
end

function Root.handle(action: string, target: string, _value: string)
    if action == "counter.add" and target == "counter/add" then
        count += 1
    elseif action == "counter.save" and target == "counter/save" then
        local snapshot = State.encode(1, { count = tostring(count) })
        track(Host.storageSet("counter-state", snapshot), "save")
        message = "Saving…"
    elseif action == "counter.load" and target == "counter/load" then
        track(Host.storageGet("counter-state"), "load")
        message = "Loading…"
    elseif action == "counter.restore" and target == "app" then
        message = if Root.restore(_value) then "Loaded" else "Stored state is invalid"
    end
end

function Root.resolve(
    id: number,
    success: boolean,
    payload: string,
    code: string,
    _errorMessage: string
)
    local operation = pending[id]
    pending[id] = nil
    if operation == nil then return end
    if not success then message = operation .. " failed: " .. code return end
    if operation == "save" then message = "Saved"
    elseif Root.restore(payload) then message = "Loaded"
    else message = "Stored state is invalid" end
end

function Root.snapshot()
    return { count = count, message = message }
end

return App.compose {
    render = function(_outputs) return Root.render() end,
    handle = Root.handle,
    resolve = Root.resolve,
    snapshot = Root.snapshot,
}

Complete inventory