Event-driven limitation

It solves problem of unnecessary computation, but makes hard to track which inputs affect which computations.

temp_c <- DynamicValue$new()
temp_c$onUpdate(function(value) {
  message("Converting") 
  temp_f <<- (value * 9 / 5) + 32
})

temp_c$set(10)
#> Converting
temp_f
#> [1] 50

temp_c$set(-3)
#> Converting
temp_f
#> [1] 26.6