callbacks.R

#' Callbacks
#'
#' Binds events to chart interactions.
#'
#' @inheritParams e_bar
#' @param query Condistion that triggers the handler
#' @param handler JavaSscript handler, passed to \link[htmlwidgets]{JS}.
#' @param event Event that triggers the handler.
#'
#' @examples
#' cars |>
#'   e_charts(speed) |>
#'   e_scatter(dist) |>
#'   e_on(
#'     list(seriesName = "dist"),
#'     "function(){alert('Serie clicked')}"
#'   )
#' @seealso \href{https://echarts.apache.org/en/api.html#echartsInstance.on}{official documentation}
#'
#' @name callbacks
#' @export
e_on <- function(e, query, handler, event = "click") {
  if (missing(query) || missing(handler)) {
    stop("must pass query and handler", call. = FALSE)
  }

  if (!length(e$x$on)) {
    e$x$on <- list()
  }

  opts <- list(
    event = event,
    query = query,
    handler = htmlwidgets::JS(handler)
  )

  e$x$on <- append(e$x$on, list(opts))

  e
}

#' @rdname callbacks
#' @export
e_off <- function(e, query, handler, event = "click") {
  if (missing(query) || missing(handler)) {
    stop("must pass query and handler", call. = FALSE)
  }

  if (!length(e$x$off)) {
    e$x$off <- list()
  }

  opts <- list(
    event = event,
    query = query,
    handler = htmlwidgets::JS(handler)
  )

  e$x$off <- append(e$x$off, list(opts))

  e
}


#' Blank Area
#' 
#' Use this function to capture a click on a
#' blank area of the canvas.
#' Note that this may stops other "click" events
#' from working.
#' 
#' @export 
e_get_zr <- function(){
  e$x$zr <- TRUE
  e
}