Event handlers — on • termr

on() creates an event handler that can be passed to app() together with the widgets. It is equivalent to calling app$on().

Usage

on(type, selector = NULL, handler)

Arguments

type: Event type such as "button.pressed", "input.submitted", "key", "resize", "focus" or "mount". "*" matches any type.
selector: Optional selector (e.g. "#hello", ".danger", "Button") matched against the sender (for key and mouse events: the widget the event was sent to).
handler: function(event, app).

Value

An object of class termr_handler.

Details

The handler runs when an event of the given type reaches the app and, if a selector is given, the widget that sent the event matches it.

Examples

on("button.pressed", "#hello", function(event, app) {
  app$query_one("#output")$update("Hello!")
})
#> $type
#> [1] "button.pressed"
#> 
#> $selector
#> [1] "#hello"
#> 
#> $handler
#> function (event, app) 
#> {
#>     app$query_one("#output")$update("Hello!")
#> }
#> <environment: 0x5641936f57f0>
#> 
#> attr(,"class")
#> [1] "termr_handler"