How to set date axis ticks and labels for all bars?

Question

The problem I have is that I can't find a solution to let me set the x-axis ticks and labels I want for a bar chart with dates on the x-axis.

I am using the echarts4r package to plot a bar plot. By default the x-axis labels are auto populated. Can I set the date labels and ticks so that they are shown for all the bars?

(I have tried a hacky work-around of converting the dates to categories but this creates problems because I want to mark additional lines at different dates than the bars are for which I can't if using categories.)

Here is a reproducible example:

library(echarts4r)

df <- data.frame(
  date = as.Date(c(paste0(2010:2020, "-06-30"))),
  value = 1:11
)

df |> 
  e_charts(date) |> 
  e_bar(value, name = "value") |>
  e_x_axis(
    axisLabel = list(
      formatter = '{yyyy}-{MM}'
    )
  )

This marks ticks and labels at '2012-01', '2014-01', '2016-01', '2018-01', '2020-01'. But I want tick and labels next to all 11 bars.

From the apache docs there are xAxis.axisTick.interval and xAxis.axisLabel.interval settings but not when the axis is time.

It might be possible with a more complicated formatter callback function but I couldn't get this working.

Answer 1

Here is an option which following the example in the docs uses maxInterval to make sure that the gap between axis labels is less than or equal to one year (But don't ask me why we have to multiply by 1000. Perhaps milliseconds?). Additionally I used min and max to add labels at the lower and upper end.

library(echarts4r)

df <- data.frame(
  date = as.Date(c(paste0(2010:2020, "-06-30"))),
  value = 1:11
)

df |>
  e_charts(date) |>
  e_bar(value, name = "value") |>
  e_x_axis(
    axisLabel = list(
      formatter = "{yyyy}-{MM}"
    ),
    min = "2010-01-01",
    max = "2021-01-01",
    maxInterval = 60 * 60 * 24 * 1000 * 366
  )