Echarts4r : Create stacked area chart with percentage from total in tooltip

Question

I need to make stacked area chart using the echarts4r. In spite of great examples on javascript I can't find the solution how to make the area chart stacked using R.

Ideally it is also necessary to add to the chart the tooltip with percentage from total as in my example using highcharter package.

library(echarts4r)
library(highcharter)

set.seed(2018)
dt <- data.frame(a =1:10,
                 x = rnorm(10, mean = 20, sd = 5), 
                 y = rnorm(10, mean = 20, sd = 5),
                 z = rnorm(10, mean = 10, sd = 5))


echarts <- dt %>%
  e_charts(a) %>%
  e_area(x, stack = "stack", origin = 'start') %>%
  e_area(y, stack = "stack", origin = 'start') %>%
  e_area(z, stack = "stack", origin = 'start') %>%
  e_grid(left = '4%', right = '3%', bottom = '10%', containLabel = true) %>%
  e_tooltip(trigger = "axis", axisPointer = list(type = 'cross')) %>%
  e_toolbox(left = 'right', itemSize = 15, top = 22) %>%
  e_toolbox_feature("saveAsImage", title = 'save as image') %>%
  e_toolbox_feature("dataZoom", title = list(zoom = "zoom", back = "back")) %>%
  e_toolbox_feature("restore", title = 'restore') %>%
  e_theme("infographic") %>%
  e_legend(type = 'scroll', bottom = 1)

echarts

highchart <-  highchart() %>%
  hc_xAxis(categories = dt$a) %>%
  hc_add_series(data = dt$x, name = 'x') %>%
  hc_add_series(data = dt$y, name = 'y') %>%
  hc_add_series(data = dt$z, name = 'z') %>%
  hc_chart(type = "area") %>%
  hc_plotOptions(area = list(stacking = "normal", lineColor = "#ffffff",
                             lineWidth = 1, marker = list( lineWidth = 1,
                                                           lineColor = "#ffffff"))) %>%
  hc_legend(reversed = FALSE) %>%
  hc_tooltip(crosshairs = TRUE, backgroundColor = "#FCFFC5", shared = TRUE, borderWidth = 5, 
             pointFormat = "<span style=\"color:{series.color}\">{series.name}</span>:
                 <b>{point.percentage:.1f}%</b> ({point.y:,.0f} users)<br/>") 

highchart

Answer 1

One way of doing it, very similar to highcharter:

dt %>%
    e_charts(a) %>%
    e_area(x, stack = "stack", origin = 'start') %>%
    e_area(y, stack = "stack", origin = 'start') %>%
    e_area(z, stack = "stack", origin = 'start') %>%
    e_grid(left = '4%', right = '3%', bottom = '10%', containLabel = TRUE) %>%
    e_toolbox(left = 'right', itemSize = 15, top = 22) %>%
    e_toolbox_feature("saveAsImage", title = 'save as image') %>%
    e_toolbox_feature("dataZoom", title = list(zoom = "zoom", back = "back")) %>%
    e_toolbox_feature("restore", title = 'restore') %>%
    e_theme("infographic") %>%
    e_legend(type = 'scroll', bottom = 1) %>%
    e_tooltip( trigger ="axis",
              formatter = htmlwidgets::JS("
              function(params){
                var tot = params[0].name + params[1].value[0] + params[2].value[0]
                function perc(x){return(Math.round((x/tot) * 100))};
                return('x: ' + params[0].value[1] + ' (' + perc(params[0].value[1]) + '%)' + '<br>' + 'y:' + params[1].value[1] + ' (' + perc(params[1].value[1]) + '%)' + '<br>' + 'z:' + params[2].value[1] + ' (' + perc(params[2].value[1]) + '%)')
                                          }
              ")
              )

More information on tooltips on the website.

EDIT Thanks for your comment, sorry I omitted part of the question. For some reason, a reason I was not aware of, stacking only works with categorical x axis. Below are two options to get there:

# options one use character or vector.
dt %>% 
    dplyr::mutate(a = as.character(a)) %>% 
    e_charts(a) %>%
    e_area(x, stack = "stack") %>%
    e_area(y, stack = "stack") %>%
    e_area(z, stack = "stack") %>%
    e_grid(left = '4%', right = '3%', bottom = '10%') %>%
    e_toolbox(left = 'right', itemSize = 15, top = 22) %>%
    e_toolbox_feature("saveAsImage", title = 'save as image') %>%
    e_toolbox_feature("restore", title = 'restore') %>%
    e_theme("infographic") %>%
    e_legend(bottom = 1) %>%
    e_tooltip( trigger ="axis",
               formatter = htmlwidgets::JS("
                                           function(params){
                                           var tot = params[0].name + params[1].value[0] + params[2].value[0]
                                           function perc(x){return(Math.round((x/tot) * 100))};
                                           return('x: ' + params[0].value[1] + ' (' + perc(params[0].value[1]) + '%)' + '<br>' + 'y:' + params[1].value[1] + ' (' + perc(params[1].value[1]) + '%)' + '<br>' + 'z:' + params[2].value[1] + ' (' + perc(params[2].value[1]) + '%)')
                                           }
                                           ")
               ) 

# option 2
# Use e_x_axis to change the axis type
dt %>% 
    e_charts(a) %>%
    e_area(x, stack = "stack") %>%
    e_area(y, stack = "stack") %>%
    e_area(z, stack = "stack") %>%
    e_grid(left = '4%', right = '3%', bottom = '10%') %>%
    e_toolbox(left = 'right', itemSize = 15, top = 22) %>%
    e_toolbox_feature("saveAsImage", title = 'save as image') %>%
    e_toolbox_feature("restore", title = 'restore') %>%
    e_theme("infographic") %>%
    e_legend(bottom = 1) %>%
    e_tooltip( trigger ="axis",
               formatter = htmlwidgets::JS("
                                           function(params){
                                           var tot = params[0].name + params[1].value[0] + params[2].value[0]
                                           function perc(x){return(Math.round((x/tot) * 100))};
                                           return('x: ' + params[0].value[1] + ' (' + perc(params[0].value[1]) + '%)' + '<br>' + 'y:' + params[1].value[1] + ' (' + perc(params[1].value[1]) + '%)' + '<br>' + 'z:' + params[2].value[1] + ' (' + perc(params[2].value[1]) + '%)')
                                           }
                                           ")
               ) %>%
  e_x_axis(type = "category")