Function debounce

Creates a debounced function that delays invoking func until after wait milliseconds have elapsed since the last time the debounced function was invoked, or until the next browser frame is drawn. The debounced function comes with a cancel method to cancel delayed func invocations and a flush method to immediately invoke them. Provide options to indicate whether func should be invoked on the leading and/or trailing edge of the wait timeout. The func is invoked with the last arguments provided to the debounced function. Subsequent calls to the debounced function return the result of the last func invocation.

Note: If leading and trailing options are true, func is invoked on the trailing edge of the timeout only if the debounced function is invoked more than once during the wait timeout.

If wait is 0 and leading is false, func invocation is deferred until the next tick, similar to setTimeout with a timeout of 0.

If wait is omitted in an environment with requestAnimationFrame, func invocation will be deferred until the next frame is drawn (typically about 16ms).

See David Corbacho's article for details over the differences between debounce and throttle.

Since

5.3.0

Example

// Avoid costly calculations while the window size is in flux.
jQuery(window).on('resize', debounce(calculateLayout, 150))

// Invoke `sendMail` when clicked, debouncing subsequent calls.
jQuery(element).on('click', debounce(sendMail, 300, {
  'leading': true,
  'trailing': false
}))

// Ensure `batchLog` is invoked once after 1 second of debounced calls.
const debounced = debounce(batchLog, 250, { 'maxWait': 1000 })
const source = new EventSource('/stream')
jQuery(source).on('message', debounced)

// Cancel the trailing debounced invocation.
jQuery(window).on('popstate', debounced.cancel)

// Check for pending invocations.
const status = debounced.pending() ? "Pending..." : "Ready"

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