I believe they're saying that a virtual DOM is created and updates that would cause a re-render are first applied to the virtual DOM (thus avoiding the over hea

I believe they're saying that a virtual DOM is created and updates that would cause a re-render are first applied to the virtual DOM (thus avoiding the over head of a render). The virtual and actual DOM are then compared to see which parts have changed and need to be re-rendered, which results in a net saving of CPU time. There is no constant value to store here. Perhaps you are referring to the templates, which are static and are already stored in memory?