feat: add sync validation

src/sync/validate.luau

@@ -0,0 +1,71 @@
+local isAtom = require(script.Parent.Parent.isAtom)
+
+local SAFE_KEYS = { string = true, number = true }
+local SAFE_VALUES = { string = true, number = true, boolean = true, table = true }
+
+local function isUnsafeTable(object: { [any]: any })
+	local keyType = nil
+	local objectSize = 0
+
+	-- All keys must have the same type
+	for key in object do
+		local currentType = type(key)
+
+		if not keyType and SAFE_KEYS[currentType] then
+			keyType = currentType
+		elseif keyType ~= currentType then
+			return true
+		end
+
+		objectSize += 1
+	end
+
+	-- If there are more keys than the length of the array, it's an array with
+	-- non-sequential keys.
+	if objectSize > #object and keyType == "number" then
+		return true
+	end
+
+	return false
+end
+
+local function validate(value: any, key: any, log: (string) -> ())
+	local typeOfKey = type(key)
+	local typeOfValue = type(value)
+
+	if not SAFE_KEYS[typeOfKey] then
+		return log(`Invalid key type '{typeOfKey}' at key '{key}'`)
+	elseif not SAFE_VALUES[typeOfValue] then
+		return log(`Invalid value type '{typeOfValue}' at key '{key}'`)
+	elseif typeOfValue == "table" then
+		if getmetatable(value) ~= nil then
+			return log(`Cannot sync tables with metatables! Got {value} at key '{key}'`)
+		elseif isAtom(value) then
+			return log(`Cannot sync nested atoms! Got atom '{value.debugLabel}' at key '{key}'`)
+		elseif isUnsafeTable(value) then
+			return log(
+				`Cannot sync tables unsupported by remote events! The value has the key '{key}'.\n\n`
+					.. "This can be for the following reasons:\n"
+					.. "1. The object is an array with non-sequential keys\n"
+					.. "2. The object is a dictionary with mixed key types (e.g. string and number)\n\n"
+					.. "Read more: https://create.roblox.com/docs/scripting/events/remote#argument-limitations"
+			)
+		end
+	end
+
+	if typeOfValue == "number" then
+		if value ~= value then
+			return log(`Cannot sync NaN at key '{key}'`)
+		elseif value == math.huge or value == -math.huge then
+			return log(`Cannot sync infinity at key '{key}'`)
+		end
+	elseif typeOfKey == "number" then
+		if key == math.huge or key == -math.huge then
+			return log("Cannot sync infinity as key")
+		elseif math.floor(key) ~= key then
+			return log("Cannot sync non-integer number as key")
+		end
+	end
+end
+
+return validate