Context Menu Items

library(blockr.dag)

The context menu provides actions based on what element is right-clicked in the graph.

Available Actions

Target Element	Available Actions
Canvas	• Add block • Create stack
Node (block)	• Create link • Remove block • Append block
Edge (link)	• Remove link
Combo (stack)	• Remove stack • Edit stack: add/remove blocks and change color

Creating Context Menu Entries

Context menu items are created with new_context_menu_entry():

# Context menu entry
entry <- new_context_menu_entry(
  name = "Custom Action",
  js = function(ns) "alert('Custom action')",
  action = function(board, update, ...) {
    # Server-side logic
  },
  condition = function(board, target) {
    target$type == "node"
  }
)

js can be a string representing a JavaScript function or an R function that takes the namespace ns as input and returns a string:

function(ns) {
  sprintf(
    "(value, target, current) => {
      Shiny.setInputValue('%s', true, {priority: 'event'});
    }",
    ns("add_block")
  )
}

condition is an either a boolean or an R function that takes the board and target (the clicked element) as input and returns TRUE or FALSE to determine if the entry should be shown.

Any new entry has to go inside context_menu_items.dag_extension for registration:

# Add custom context menu items to an extension
context_menu_items.dag_extension <- function(x) {
  list(
    new_context_menu_entry(
      name = "My Action",
      js = function(ns) {
        sprintf("Shiny.setInputValue('%s', true)", ns("my_action"))
      },
      action = my_custom_action("my_action"),
      condition = function(board, target) TRUE
    )
  )
}