Basalt2/docs/references/plugins/state.md

local PropertySystem = require("propertySystem") local errorManager = require("errorManager") local BaseElement = {}

function BaseElement.setup(element) element.defineProperty(element, "states", {default = {}, type = "table"}) element.defineProperty(element, "computedStates", {default = {}, type = "table"}) element.defineProperty(element, "stateUpdate", { default = {key = "", value = nil, oldValue = nil}, type = "table" }) end

function BaseElement:initializeState(name, default, canTriggerRender, persist, path) local states = self.get("states")

if states[name] then
    errorManager.error("State '" .. name .. "' already exists")
    return self
end

if persist then
    local file = path or ("states/" .. self.get("name") .. "_" .. name .. ".state")

    if fs.exists(file) then
        local f = fs.open(file, "r")
        states[name] = {
            value = textutils.unserialize(f.readAll()),
            persist = true,
            file = file
        }
        f.close()
    else
        states[name] = {
            value = default,
            persist = true,
            file = file,
            canTriggerRender = canTriggerRender
        }
    end
else
    states[name] = {
        value = default,
        canTriggerRender = canTriggerRender
    }
end
return self

end

function BaseElement:setState(name, value) local states = self.get("states") if not states[name] then error("State '"..name.."' not initialized") end

local oldValue = states[name].value
states[name].value = value

if states[name].persist then
    local dir = fs.getDir(states[name].file)
    if not fs.exists(dir) then
        fs.makeDir(dir)
    end
    local f = fs.open(states[name].file, "w")
    f.write(textutils.serialize(value))
    f.close()
end

if states[name].canTriggerRender then
    self:updateRender()
end

self.set("stateUpdate", {
    key = name,
    value = value,
    oldValue = oldValue
})
return self

end

function BaseElement:getState(name) local states = self.get("states") if not states[name] then errorManager.error("State '"..name.."' not initialized") end return states[name].value end

function BaseElement:computed(key, computeFn) local computed = self.get("computedStates") computed[key] = setmetatable({}, { __call = function() return computeFn(self) end }) return self end

function BaseElement:shareState(stateKey, ...) local value = self:getState(stateKey)

for _, element in ipairs({...}) do
    if element.get("states")[stateKey] then
        errorManager.error("Cannot share state '" .. stateKey .. "': Target element already has this state")
        return self
    end
    
    element:initializeState(stateKey, value)

    self:observe("stateUpdate", function(self, update)
        if update.key == stateKey then
            element:setState(stateKey, update.value)
        end
    end)
end
return self

end

function BaseElement:onStateChange(stateName, callback) if not self.get("states")[stateName] then errorManager.error("Cannot observe state '" .. stateName .. "': State not initialized") return self end

self:observe("stateUpdate", function(self, update)
    if update.key == stateName then
        callback(self, update.value, update.oldValue)
    end
end)
return self

end

return { BaseElement = BaseElement }