Plot 如何在Rmarkdown shinny中绘制分层时间序列

我希望按照下面的代码绘制包含在列表中的分层时间序列：
图书馆和数据创建

title: "prueba shiny"
runtime: shiny
output: html_document
---
library(dplyr)
library(tidyr)
library(dygraphs)
library(tseries)

df <- data.frame(date = c(as.yearmon(2018,1),as.yearmon(2018,1),as.yearmon(2018,2),as.yearmon(2018,2),
                          as.yearmon(2018,1),as.yearmon(2018,1),as.yearmon(2018,2),as.yearmon(2018,2)),                sales = c(1,2,3,4),
                 cat_I = c("drink","drink","food","food","drink","drink","food","food"),
                 cat_II = c("cola","fanta","tomatoes","bananas","cola","fanta","tomatoes","bananas"))

cat <- data.frame(I = c("drink","drink","food","food"),
                  II = c("cola","fanta","tomatoes","bananas"))

我希望通过从selectInput中选择类别来创建这两个图。我试过这样的方法但没有成功：

selectInput("I", label = "category_I:",
           choices = unique(cat$I), selected = cat$I[1])
selectInput("II", label = "II", choices = unique(cat$II))

plotOutput(outputId = "dy")

data <- reactive({
  ts_I_II$input$II})

output$dy <- renderPlot({
   dygraph(data)

选择输入（“I”，label=“category\u I:”，
选项=唯一（类别$I），选中=类别$I[1]）
选择输入（“II”，label=“II”，choices=unique（类别$II））
plotOutput（outputId=“dy”）
数据
aux <- with(cat,split(II,I))
ts_I_II <-  lapply(aux, function(x) ts[x])

catI_sales <- list()
for (s in unique(cat$I)){
  catI_sales[[s]] <- do.call(cbind,ts_I_II[[s]])
}

aux <- do.call(cbind,ts_I_II$drink)
dygraph(aux, main = "sales by cat_II") %>% dyOptions(colors = RColorBrewer::brewer.pal(5, "Set2"))

dygraph(ts_I_II$drink$cola, main = "sales by cat_II") %>% dyOptions(colors = RColorBrewer::brewer.pal(5, "Set2"))



selectInput("I", label = "category_I:",
           choices = unique(cat$I), selected = cat$I[1])
selectInput("II", label = "II", choices = unique(cat$II))

plotOutput(outputId = "dy")

data <- reactive({
  ts_I_II$input$II})

output$dy <- renderPlot({
   dygraph(data)


selectInput("II", label = "category_II:",
           choices = names(ts))


dygraphs::renderDygraph({
  dygraph(ts[[input$II]])
})
  
selectInput("I", label = "category_I:",
           choices = names(catI_sales))


dygraphs::renderDygraph({
  dygraph(catI_sales[[input$I]])
})