drift-zoom/src/js/util/debounce.js

Easily add "zoom on hover" functionality to your site's images. Lightweight, no-dependency JavaScript.

/* eslint-disable */
// http://underscorejs.org/docs/underscore.html#section-83
export default function debounce(func, wait, immediate) {
  let timeout;
  let args;
  let context;
  let timestamp;
  let result;

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

    if (last < wait && last >= 0) {
      timeout = setTimeout(later, wait - last);
    } else {
      timeout = null;

      if (!immediate) {
        result = func.apply(context, args);

        if (!timeout) {
          context = args = null;
        }
      }
    }
  };

  return function() {
    context = this;
    args = arguments;
    timestamp = Date.now();

    const callNow = immediate && !timeout;

    if (!timeout) {
      timeout = setTimeout(later, wait);
    }

    if (callNow) {
      result = func.apply(context, args);
      context = args = null;
    }

    return result;
  };
}