R shiny custom function

Question

I'm trying to call a reactive function within my custom function and I couldn't. What is the best way to do this, here is the simplified code and I can't pass everything as a functional parameter because there will be too many to pass.

  library(shiny); 
  myf<-function(){ return(psd()$y) }
  shinyApp( ui = textOutput("test2"), 
      server = function(input, output) {
          psd<-reactive({ return(data.frame(x=10,y=30)) })
          output$test2 <- renderText({ myf() })
        }
      )

This code generates an error : Error in myf() : could not find function "psd" What is the best way to call custom function which utilizes other function from within shinyserver?

Answer 1

It depends if you want your function to be reactive as well or not.

In the case of reactivity use:

myf <- reactive({return(psd()$y})

If you don't want it to be reactive use

 myf <- function() {return(isolate(psd$y))}

---

Your reactive expression does not have a reactive Value (like input$). Therefore it does not get created. To understand reactivity better read this awesome instruction.

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Furthermore maybe you try to avoid hardcoding and try to add the reactive function you want to call as a parameter in your function, like this:

myf<-function(func){ return(func()$y) }

And then:

output$test2 <- renderText({ myf(psd) })