build-shiny-module

# Build Shiny Module Create reusable Shiny UI/server module pairs with proper namespace isolation, reactive communication, and composability. ## When to Use - Extracting a reusable component from a growing Shiny app - Building a UI widget that will be used in multiple places - Encapsulating complex reactive logic behind a clean interface - Composing larger applications from smaller, testable units ## Inputs - **Required**: Module purpose and functionality description - **Required**: Input/output contract (what the module receives and returns) - **Optional**: Whether the module nests other modules (default: no) - **Optional**: Framework context (golem, rhino, or vanilla) ## Procedure ### Step 1: Define the Module Interface Before writing code, define what the module accepts and returns: ```text Module: data_filter Inputs: reactive dataset, column names to filter on Outputs: reactive filtered dataset UI: filter controls (selectInput, sliderInput, dateRangeInput) ``` **Got:** Clear contract specifying reactive inputs, reactive outputs, and UI elements. **If fail:** If the interface is unclear, the module is probably too broad. Split it into smaller modules with single responsibilities. ### Step 2: Create the Module UI Function ```r #' Data Filter Module UI #' #' @param id Module namespace ID #' @return A tagList of filter controls #' @export dataFilterUI <- function(id) { ns <- NS(id) tagList( selectInput( ns("column"), "Filter column", cho...