Event timing and transport config

Configure how event callbacks are dispatched from the browser to the server. Pass the result to an element's .event prop to control timing for all events on that element (auto-bind synthetic write-back plus any explicit on* handlers).

Usage

event_immediate(coalesce = FALSE)

event_throttle(ms, leading = TRUE, coalesce = TRUE)

event_debounce(ms, coalesce = TRUE)

Arguments

coalesce

If TRUE, gate on server idle so events never queue faster than the server can process them. Defaults to FALSE for event_immediate() and TRUE for event_throttle()/event_debounce().

ms

Minimum interval (throttle) or quiet period (debounce) in milliseconds.

leading

If TRUE (default), fire immediately on the first event. If FALSE, wait for the timer before firing.

Value

An irid_event_config struct.

Details

• event_immediate(): Fires on every event with no rate limiting.

• event_throttle(): Fires at most every ms milliseconds while the event is active.

• event_debounce(): Waits until the user pauses for ms milliseconds before firing.

When .event is omitted, irid applies a per-event default keyed on the DOM event name: input → event_debounce(200) (typing produces a flood of intermediate values), every other event → event_immediate(). The rule is the same whether the event entry came from an auto-bind synthetic or an explicit on* handler, so adding value = rv to an existing onInput doesn't silently shift its timing.

.event accepts either a single config struct (applies to every event on the element) or a named list for per-event overrides. List keys may use either the lowercase DOM event name (input, change, keydown) or the matching on-prop name (onInput, onChange, onKeyDown); both forms normalize to the lowercase DOM event. Events not covered by the list fall back to the per-event default. Malformed .event values (a non-config, an unnamed list, or a list whose entries are not all configs) raise an error during tag processing.

Use the element-level .prevent_default prop to call event.preventDefault() in the browser before dispatch. Like .event, it accepts either a logical scalar (broadcasts to every event on the element) or a named list keyed by DOM event for per-event overrides; unmapped events default to FALSE.

The event object

The event argument passed to handlers is a list containing all primitive-valued properties (string, numeric, logical) from the browser event object, plus these element properties:

value

The element's current value (character).

valueAsNumber

Numeric value of the element, or NA if the input is empty or non-numeric (e.g. a blank text box). Useful for range and number inputs.

checked

Logical, for checkbox and radio inputs.

Keyboard events additionally include key, code, ctrlKey, shiftKey, altKey, and metaKey.