Add multiple x axis

[XR97]

I want to add the custom second xAxis and the code as follows, but the generated JS seems to be wrong.
The mechanism of add xAxis is different between yAxis? Or it is a bug?

library(echarts4r)
library(magrittr)
library(data.table)

dt <- data.table(
  x_label = c('A', 'B', 'C', 'D', 'D', 'D', 'D'),
  x_value = c('a', 'b', 'c', 'd', 'e', 'f', 'g'),
  y = 8:14
)
p <- e_charts(dt)
p <- e_x_axis(p, index = 0, data = purrr::map(seq_len(nrow(dt)), ~{list(value = dt[.x, x_label])}))
p <- e_x_axis(p, index = 1, data = purrr::map(seq_len(nrow(dt)), ~{list(value = dt[.x, x_value])}))

json <- p %>%
  e_inspect(
    json = TRUE,
    pretty = TRUE
  )


> json
{
  "yAxis": [
    {
      "show": true
    }
  ],
  "xAxis": {
    "data": {
      "1": {
        "value": "A"
      },
      "2": {
        "value": "B"
      },
      "3": {
        "value": "C"
      },
      "4": {
        "value": "D"
      },
      "5": {
        "value": "D"
      },
      "6": {
        "value": "D"
      },
      "7": {
        "value": "D"
      },
      "data": [
        {
          "value": "a"
        },
        {
          "value": "b"
        },
        {
          "value": "c"
        },
        {
          "value": "d"
        },
        {
          "value": "e"
        },
        {
          "value": "f"
        },
        {
          "value": "g"
        }
      ]
    }
  }
} 

[rdatasculptor]

@XR97 On my machine your code simply doesn't work. I am not sure how your chart needs to be look like. You say there is no problem if you treat the yAxis this way. Can you give an example?