SafeWaitForChild.lua

local Promise = require(script.Parent.Parent.Vendor.Promise)

local function SafeWaitForChild(Parent, ChildName, Timeout)
	return Promise.new(function(Resolve, Reject, OnCancel)
		local Child = Parent:FindFirstChild(ChildName)
		if Child then
			Resolve(Child)
		else
			local Offset = Timeout or 5
			local StartTime = os.clock()
			local Cancelled = false
			local Connection

			OnCancel(function()
				Cancelled = true
				if Connection then
					Connection = Connection:Disconnect()
				end

				return Reject("SafeWaitForChild(" .. Parent:GetFullName() .. ", \"" .. tostring(ChildName) .. "\") was cancelled.")
			end)

			Connection = Parent:GetPropertyChangedSignal("Parent"):Connect(function()
				if not Parent.Parent then
					if Connection then
						Connection = Connection:Disconnect()
					end

					Cancelled = true
					return Reject("SafeWaitForChild(" .. Parent:GetFullName() .. ", \"" .. tostring(ChildName) .. "\") was cancelled.")
				end
			end)

			repeat
				Promise.Delay(0.03):Await()
				Child = Parent:FindFirstChild(ChildName)
			until Child or StartTime + Offset < os.clock() or Cancelled

			if Connection then
				Connection = Connection:Disconnect()
			end

			if not Timeout then
				Reject("Infinite yield possible for SafeWaitForChild(" .. Parent:GetFullName() .. ", \"" .. tostring(ChildName) .. "\")")
			elseif Child then
				Resolve(Child)
			end
		end
	end)
end

return SafeWaitForChild