how to change the line width based on variables in the data

Customised.R

library(echarts4r)

flights <- read.csv(
  paste0("https://raw.githubusercontent.com/plotly/datasets/",
         "master/2011_february_aa_flight_paths.csv")
)

flights <- flights %>% 
  dplyr::mutate(width = scales::rescale(cnt, to = c(0, 5)))

# More icons available with 
# echarts.assets
# https://echarts4r-assets.john-coene.com/
icon <- 'path://M1705.06,1318.313v-89.254l-319.9-221.799l0.073-208.063c0.521-84.662-26.629-121.796-63.961-121.491c-37.332-0.305-64.482,36.829-63.961,121.491l0.073,208.063l-319.9,221.799v89.254l330.343-157.288l12.238,241.308l-134.449,92.931l0.531,42.034l175.125-42.917l175.125,42.917l0.531-42.034l-134.449-92.931l12.238-241.308L1705.06,1318.313z'

flights %>%
  e_charts() %>%
  e_geo() %>%
  e_lines(
    start_lon,
    start_lat,
    end_lon,
    end_lat,
    airport1,
    airport2,
    cnt,
    name = "flights",
    effect = list(
      show = TRUE,
      symbol = icon,
      trailLength = .1
    ),
    lineStyle = list(
      curveness = .5,
      color = list(
        type = "linear",
        x = 0,
        y = 0,
        x2 = 0,
        y2 = 1,
        colorStops = list(
          list(
            offset = 0, 
            color = 'red'
          ),
          list(
            offset = 1, 
            color = 'blue'
          )
        ),
        global = FALSE
      )
    )
  ) %>% 
  e_add("lineStyle", width) 

line_gradient.R

library(echarts4r)

flights <- read.csv(
  paste0("https://raw.githubusercontent.com/plotly/datasets/",
         "master/2011_february_aa_flight_paths.csv")
)

flights <- flights[100:150,] %>% 
  dplyr::filter(airport1 %in% c('ORD')) %>%  ## reduce data to see the pattern
  dplyr::mutate(width = scales::rescale(cnt, to = c(0, 7))) 
  

# More icons available with 
# echarts.assets
# https://echarts4r-assets.john-coene.com/
icon <- 'path://M1705.06,1318.313v-89.254l-319.9-221.799l0.073-208.063c0.521-84.662-26.629-121.796-63.961-121.491c-37.332-0.305-64.482,36.829-63.961,121.491l0.073,208.063l-319.9,221.799v89.254l330.343-157.288l12.238,241.308l-134.449,92.931l0.531,42.034l175.125-42.917l175.125,42.917l0.531-42.034l-134.449-92.931l12.238-241.308L1705.06,1318.313z'

library(echarts4r.maps)

flights %>%
  e_charts() %>%
  e_geo("USA") %>%
  em_map("USA") %>% # sub-national maps
  e_lines(
    start_lon,
    start_lat,
    end_lon,
    end_lat,
    airport1,
    airport2,
    cnt,
    name = "flights",
    effect = list(
      show = TRUE,
      symbol = icon,
      trailLength = .1
    ),
    lineStyle = list(
      curveness = .5,
      color = htmlwidgets::JS("new echarts.graphic.LinearGradient(0, 0, 0, 1, [{
                        offset: 0, color: '#58B3CC'
                    }, {
                        offset: 1, color: '#F58158'
                    }], false)")
    )
  ) %>% 
  e_add("lineStyle", width) 

lines_width.R

library(echarts4r)

flights <- read.csv(
  paste0("https://raw.githubusercontent.com/plotly/datasets/",
         "master/2011_february_aa_flight_paths.csv")
)

flights <- flights %>% 
  dplyr::mutate(width = scales::rescale(cnt, to = c(0, 5)))

flights %>%
  e_charts() %>%
  e_geo() %>%
  e_lines(
    start_lon,
    start_lat,
    end_lon,
    end_lat,
    airport1,
    airport2,
    cnt,
    name = "flights"
  ) %>% 
  e_add("lineStyle", width)