Time tests for reactives

reactive_times.R

library(shiny)
# Reactives with no changes (after first)
v <- reactiveValues(x = 0)
r0 <- reactive(1)           # 0 levels of dependence
r1 <- reactive(v$x)         # 1 level
r2 <- reactive(r1())        # 2 levels


# Reactives with change
vc <- reactiveValues(x = 0)
rc1 <- reactive(vc$x)
f_rc1 <- function() {
  vc$x <- vc$x + 1
  rc1()
}
rc2 <- reactive(rc1())
f_rc2 <- function() {
  vc$x <- vc$x + 1
  rc2()
}

library(microbenchmark)
isolate(microbenchmark(
  v$x,               # Use reactive value directly
  r0(),              # reactive with 0 levels
  r1(),              # reactive with 1 level
  r2(),              # reactive with 2 levels
  vc$x <- vc$x + 1,  # Change reactive value
  f_rc1(),           # Change reactive value, then call a dependent reactive (1 level)
  f_rc2()            # Change reactive value, then call a dependent reactive (2 levels)
))