throttle

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Basic usage

Throttle accepts an options object with an interval and a source function to call when invoked. When the returned function is invoked it will only call the source function if the interval milliseconds of time has passed. Otherwise, it will ignore the invocation. The leading option decides whether the source function is called on the first invocation of the throttle function or not.

import { throttle } from 'radash'

const onMouseMove = () => {
  rerender()
}

addEventListener(
  'mousemove',
  throttle({ interval: 200, leading = false }, onMouseMove)
)

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Timing & Leading

A visual of the throttle behavior when interval is 200 and leading is in different values. The throttle function returned by throttle can be called every millisecond but it will only call the given callback after interval milliseconds have passed. The leading option, true by default, will delay the execution cycle of source function by one interval as a whole when set to false.

                           Time: 0ms - - - - 200ms - - - - 400ms - - - - 600ms - - - - 800ms - - - -
           Throttle Invocations: x x x x x x x x x x x x x x x x x x x x x x x - - - - - - - - - - -
    Source Invocations(leading): x - - - - - x - - - - - - x - - - - - - x - - - - - - - - - - - - -
Source Invocations(not leading): - - - - - - x - - - - - - x - - - - - - x - - - - - - x - - - - - -

​

isThrottled

The function returned by throttle has a isThrottled method that when called will return if there is any active throttle.

const debounced = throttle({ interval: 200 }, onMouseMove)

// ... sometime later

debounced.isThrottled()