problem with noUiSliderInput output having only 2 decimals - r

Question

I'm trying to link a log scaled noUiSliderInput with a linear scaled numericInput without creating an eternal update loop.
Normally I would stop the update lines with this:
input$Histoslider != log10(input$Threshold_box)
This created some issues with decimals, which I can't seem to fix properly.
The main problem seems to be that noUiSliderInput always rounds its output to 2 decimals, causing the rounding problem for the conversion to 10^ and log10 back and forth
Detailed description:
I have an app where the user can set threshold filters in 2 ways:
1: type the number in a numericInput in un-transformed numbers
or
2: by changing the bar on a vertical noUiSliderInput.
The noUiSliderInput however is expressed as log10 numbers, as it is lined up with a plot of the data on log10 scale. so if the plot runs from 10^-1 to 10^4.5, the slider has values running from -1 to 4.5
The numericInput and noUiSliderInputare linked, so change one should update the other.
This created a lot of difficulty with decimals. The numericInput has to be restricted in the app to 2 decimals. So to do that I add some transformation, rounding and transformation back again to get matching numbers.
I can get it to work for a normal sliderInput, but somehow not for a noUiSliderInput, eventhough they should spit out the same format of data.
The reason I have to stick with a noUiSliderInput is because I need a slider on both the x and y axis of the plot.
Try to type 1256 in the numericInput to see an example of the problem
The app:
# install.packages("devtools")
devtools::install_github("dreamRs/shinyWidgets")
library(shiny)
library(shinyWidgets)
# function to see how many decimal places we need
decimalplaces <- function(x) {
if ((x %% 1) != 0) {
deci <- nchar(strsplit(sub('0+$', '', as.character(x)), ".", fixed=TRUE)[[1]][[2]])
if(deci >2) { deci <- 2}
return(deci)
} else {
return(0)
}
}
# starting values for the sliders
minval <- round(-1, digits = 6)
maxval <- round(4.5, digits = 6)
ui <- fluidPage(
tags$br(),
fluidRow(
column(3,
div(numericInput("Threshold_box", "Normal value: ", min = 0, max = 100, value = 1, step=0.01), style = "display:inline-block") ),
column(2,
# div(sliderInput( inputId = "Histoslider", label = NULL, min = minval, max = maxval, value = 0, step = 0.000001), style = 'display:inline-block; position:relative')
noUiSliderInput(inputId = "Histoslider", label = NULL, min = minval, max = maxval, tooltips = FALSE, value = 0, step = 0.000001, direction = "rtl", orientation = "vertical", width = "100px", height = "276px")
)))
server <- function(input, output, session) {
#setting decimals to 6 as that seemed to work in the end for a normal sliderInput
values <- reactiveValues( transformDecimal = 2)
observeEvent(input$Threshold_box, {
if(!is.na(input$Threshold_box)) { values$transformDecimal <- decimalplaces(input$Threshold_box)
if(input$Histoslider != log10(input$Threshold_box)) {
newval <- log10(input$Threshold_box)
# updateSliderInput(session, 'Histoslider', value = newval)
updateNoUiSliderInput(session, 'Histoslider', value = newval)
}}}, ignoreInit = T)
observeEvent(input$Histoslider, {
## next three lines are to get matching set between a 2 decimal numer and the log value
sliderFull <- 10^input$Histoslider
sliderRound <- round(sliderFull, digits = values$transformDecimal)
sliderLog <- log10(sliderRound)
updateSliderInput(session, 'Histoslider', value = sliderLog)
if(sliderLog != log10(input$Threshold_box)) {
updateNumericInput(session, 'Threshold_box', value = round(10^sliderLog, digits = values$transformDecimal))
}
}, ignoreInit = T)
}
shinyApp(ui, server)