ExplorerClass: Explorer Class
In DavidBarke/shinyExplorer: Explorer and Contextmenu for Shiny apps

Description Methods UI list Server function

R6Class, whose instantiations represent individual behaviour of a specific group of elements inside the explorer module. For creating your own explorer class see the explorer class vignette: vignette("explorer_class", package = "shinyExplorer").

new(id, ui, server, label = NULL, on_remove = function(node) NULL)

Initialise a new object of class ExplorerClass.

`id`	Unique id.
`ui`	A list of UI functions. See 'UI list' for details.
`server`	Module server function. See 'Server function' for return list elements that get handled by `explorer` and `explorer_body`.
`label`	`Character` vector of labels associated with this class. The `id` is always treated as a label as well. Different explorer classes can't share the same ids but they can have common labels.

The argument ui receives a named list of ui functions - these are functions taking at least an argument id and returning pseudo-HTML. The following names are handled by explorer:

`contextmenu_item_ui`	Function returning a `contextmenu_item`, which is displayed in the contextmenu, if this explorer_class is addable in the `explorer` or `explorer_selector`. Clicking on this contextmenu_item usually adds a new node of this explorer class as a child node to the contextmenued node.
`specific_contextmenu_items_ui`	Function returning a `tagList` of `contextmenu_items`. These contextmenu items are part of the contextmenu which is displayed upon contextmenuing a node of this explorer class.

These functions only provide the layout of the items. The functionality must be implemented in the server function.

The following (and only these) return list elements are handled by explorer and explorer_body:

`selectable_classes_r`	`Reactive` returning a character vector containing the `id`s of `explorer_classes` who can be added to the `explorer`, if the current `explorer_class` has `id = id`. Returning `NULL` results in no possible selection. Returning of `""` results in possible selection of all `explorer_classes`. If the server function does not return this reactive, all `explorer_classes` are selectable.
`icon_r`	`Reactive` returning a `icon`, which is displayed in the `explorer_body`.
`on_remove`	`Function`, which is called just before a node of this explorer class is removed from a tree. This function receives the target node as the only argument.