@lightningjs/sdk/src/Accessibility/Announcer/utils.js

The Lightning-SDK helps you build great Lightning-based TV apps!

/*
 * If not stated otherwise in this file or this component's LICENSE file the
 * following copyright and licenses apply:
 *
 * Copyright 2020 Metrological
 *
 * Licensed under the Apache License, Version 2.0 (the License);
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Code from: https://github.com/jashkenas/underscore is
 * Copyright (c) 2009-2022 Jeremy Ashkenas, Julian Gonggrijp, and DocumentCloud and Investigative Reporters & Editors
 * Licensed under the MIT License based off:
 * http://unscriptable.com/2009/03/20/debouncing-javascript-methods/ which is:
 * Copyright (c) 2007-2009 unscriptable.com and John M. Hann
 * Licensed under the MIT License (with X11 advertising exception)
 */

export function getElmName(elm) {
  return elm.ref || elm.constructor.name
}

/**
 * Returns a function, that, as long as it continues to be invoked, will not
 * be triggered. The function will be called after it stops being called for
 * N milliseconds. If `immediate` is passed, trigger the function on the
 * leading edge, instead of the trailing. The function also has a property 'clear'
 * that is a function which will clear the timer to prevent previously scheduled executions.
 *
 * @source underscore.js
 * @see http://unscriptable.com/2009/03/20/debouncing-javascript-methods/
 * @param {Function} function to wrap
 * @param {Number} timeout in ms (`100`)
 * @param {Boolean} whether to execute at the beginning (`false`)
 * @api public
 */
export function debounce(func, wait, immediate) {
  var timeout, args, context, timestamp, result
  if (null == wait) wait = 100

  function later() {
    var last = Date.now() - timestamp

    if (last < wait && last >= 0) {
      timeout = setTimeout(later, wait - last)
    } else {
      timeout = null
      if (!immediate) {
        result = func.apply(context, args)
        context = args = null
      }
    }
  }

  var debounced = function() {
    context = this
    args = arguments
    timestamp = Date.now()
    var callNow = immediate && !timeout
    if (!timeout) timeout = setTimeout(later, wait)
    if (callNow) {
      result = func.apply(context, args)
      context = args = null
    }

    return result
  }

  debounced.clear = function() {
    if (timeout) {
      clearTimeout(timeout)
      timeout = null
    }
  }

  debounced.flush = function() {
    if (timeout) {
      result = func.apply(context, args)
      context = args = null

      clearTimeout(timeout)
      timeout = null
    }
  }

  return debounced
}