Watch a task board for changes (event-driven coordinator engine)

Wraps watcher::watcher() on the board file so a coordinator / live Shiny view reacts to board changes the instant they land, instead of polling. callback is invoked (with the changed paths) on every write to the board. Returns the started watcher (call $stop() when done), or NULL when the watcher package is unavailable – callers then fall back to polling (mirrors how Shiny uses watcher when present and polls otherwise).

Usage

board_watch(db_path, callback, latency = 0.3)

Arguments

db_path

Character. Board path.

callback

Function of one argument (changed paths).

latency

Numeric. Debounce seconds (default 0.3).

Value

A started watcher R6 object, or NULL if watcher is unavailable.