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Reactive state fields

Source: R/reactive.R
reactive.Rd

reactive() declares a state field of a custom widget (see widget()). Reading the field returns its value; assigning a different value (self$count <- self$count + 1L) invalidates the widget and schedules a repaint. Repaints are batched: any number of assignments in one event-loop tick produce a single render and a single screen diff.

Usage

reactive(value = NULL, watch = NULL)

Arguments

value

Initial value.

watch

Optional function(self, value, old) called after the value changed, e.g. to post a message or update other widgets.

Value

An object of class termr_reactive.

Examples

reactive(0L)
#> <reactive 0>
reactive("", watch = function(self, value, old) message("now ", value))
#> <reactive "" (watched)>