ostgals

// thanks to rniemeyer!
// http://www.knockmeout.net/2011/06/lazy-loading-observable-in-knockoutjs.html

ko.extenders.lazy = function(target, callback){
	
	var result = ko.computed({
		read: function(){
			if (!result.loaded()) callback.call(context);
			return target();
		},

ostgals

{
	// .....

	enqueue: function(items, get_promise, num_threads){
		num_threads = num_threads || 1;
		var dfd = $.Deferred(), i = 0, num_total = items.length, num_active = 0, num_done = 0,
			next = function(){
				while (num_active < num_threads && i < num_total) {
					num_active++;
					get_promise(items[i++]).done(function(){

ostgals

<?

$arSections = array_reduce($arResult["SECTIONS"], function($carry, $section){

	if (empty($section["IBLOCK_SECTION_ID"])) { // depth 1

		$section["LEVEL2_ITEMS"] = [];
		$carry[$section["ID"]] = $section;

	} else { // level

ostgals

// credits: http://janmatuschek.de/LatitudeLongitudeBoundingCoordinates

function dist(a, b) {
  const [a0, a1, b0, b1] = [...a, ...b].map(x => x / 180 * Math.PI);
  const { acos, sin, cos } = Math;
  return acos(sin(a0) * sin(b0) + cos(a0) * cos(b0) * cos(a1 - b1)) * 6371;
}