Component Methods

Methods are a list of functions that are contained within a given component, and typically will manipulate component data or respond to user input.

Methods can be accessed in both other methods and the component template via the self keyword.

Details

Methods are defined in the component definition as a named list of functions.

For example, the following is a method section from a simple counter component that defines two methods, setup and increment, which respectively set up the module server and increment the count state:

methods = list(
    setup = function(input, output, session) {
        output$txt <- renderText({
            paste0("Count is: ", self$count())
        })
        observeEvent(input$button, {
            self$count(self$count() + 1L)
        })
    },
    increment = function() {
        self$count(self$count() + 1L)
    }
)

Hooks

Setup

The setup hook is defined by passing a function named "setup" to the methods list. Setup is used as the module server for the component. This method is called when the module is first initialized, and is used to set up input/output bindings and any other necessary initialization code.

setup = function(input, output, session) {

}

Render

The render hook is defined by passing a function named "render" to the methods list. The render hook allows for the modification of template code prior to its rendering.

render = function(element) {

}

See also

Other components: component-data, component-styles, component-template, component()