How to use async in JavaScript?

Question

JavaScript

Good day to all! There is this code:

// получаем дистанцию
function getDistance(c, center,geoObject){
    layout.showLoading();
    var a = [];
    routeFromCenter(c,function(g,l){
        a.push(l[0]);
        var q = findNereast(jGq, c, 1),
            n = [],
            n = 3500 > getPointDistance(q[0],c) ? findNereast(jGq,c,7) : findNereast(bjGq,c,5);
        n.forEach(function(c){
            c[0] == l[0][0] && c[1] == l[0][1] || a.push(c)
        });

        async.map(a, function(a,c){
            getRoute(a,c,g)
        }, function(a,c){
            var l = g.map(function(a){
                return a.get.getLength();
            }),
            l = indexOfSmallest(l);
            
        });

    }, center,geoObject);
}

Connected:

<script type="text/javascript" src="https://api-maps.yandex.ru/2.1/?lang=ru_RU"></script>
        <script type="text/javascript" src="map.js"></script>

Gives the following error:

Uncaught ReferenceError: async is not defined
    at map.js:136
    at map.js:102
    at map.js:108
    at ?lang=ru_RU:2
    at s (?lang=ru_RU:2)
    at Array.<anonymous> (?lang=ru_RU:2)
    at n (?lang=ru_RU:2)
    at a (?lang=ru_RU:2)

Browsers: Chrome 59, Opera 46, IE 11
Similar code from mkad.mapcraft.ru works without errors. Third party libraries are not included. How to solve this problem?

Answer 1

A similar code from the site mkad.mapcraft.ru works without errors. Third party libraries are not included.

Yah?
Just the same, this is not a native object, but a self-written one. And if not from any library, then written personally by the developers of the site.
An example of a library from the first lines of Google's issuance.