subscribe-ui-event/dist-es/lib/rAFThrottle.js

A single, throttle built-in solution to subscribe to browser UI Events.

/**
 * Copyright 2015, Yahoo! Inc.
 * Copyrights licensed under the New BSD License. See the accompanying LICENSE file for terms.
 */

import rAF from 'raf';
const getTime = Date.now || /* istanbul ignore next */function () {
  return new Date().getTime();
};
function rAFThrottle(func) {
  let throttle = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 15;
  let context;
  let args;
  let last = 0;
  let requestId = 0;
  const later = function () {
    const now = getTime();
    const remaining = throttle - (now - last);
    if (remaining <= 0) {
      last = now;
      requestId = 0;
      func.apply(context, args);
    } else {
      requestId = rAF(later);
    }
  };
  return function throttledFunc() {
    context = this;
    args = arguments; // eslint-disable-line prefer-rest-params

    if (!requestId) {
      requestId = rAF(later);
    }
  };
}
export default rAFThrottle;