r - Can I save the old value of a reactive object when it changes? -

note:. come up with the answer after I question,

Sometimes a Glossy app I was chosen by the user to a widget value , As well as the previous value selected for the same widget, it may apply to the reactive values ​​derived from the user input, where I want the old and new values.

The problem is that if I try to save the value of a widget, then that variable will not be responsive to the value or updated each time the widget changes but, if I assume In a reactive context, it will always give me the current value, not the last time.

How can I save the last value of a widget, but still have it updated while changing the user widget?

Is there a way for which no action button is needed to be used, every time the user changes? Adding a actionButton can be desirable with an otherwise unnecessary and creates extra clicks for the user.

The aim is to break the session flush event method, it seems that a < Code> Inspection event is an alternative way to build and use a responsive variable.

  Library (bright) ui & lt; - fluidPage (H1 ( "Memory"), sidebarLayout (sidebarPanel (numericInput ( "VAL", "Next value", 10)), mainPanel (verbatimTextOutput ( "curval"), verbatimTextOutput ( "lstval")))) Server & Lt; - Function (Input, Output, Session) {RV & lt; - reactiveValues ​​(lstval = 0, curval = 0) observeEvent (Input $ val {RV $ lstval & lt; - RV $ curval; RV $ curval & lt; - Input $ val }) Current Issues & lt; - Reactive ({Request (Input $ val); Input $ val, RV $ curval}) lstre & lt; - Reactive ({Request (Input $ val); Input $ val, RV $ lstval} Production $ curval & lt; --renderPrint ({sprintf ("CUR:% d", current issues ())} output $ lstval & lt; - renderPrint ({sprintf ( 

Yield:

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