Sort map by its keys and return another map in Javascript

sort_map_js

sortMapByValue(map) {
    var tupleArray = [];
    for (var key in map) tupleArray.push([key, map[key]]);
    tupleArray.sort(function (a, b) {
        return b[1] - a[1]
    });
    var sortedMap = {};
    tupleArray.forEach(function (el) {
        sortedMap[el[0]] = el[1]
    });
    return sortedMap;
}