iTunes Apple Script - Create a shuffled playlist from another one

shuffle_random_playlist.scpt

(function () {
    'use strict';

    function toLower(s) {
        return s.toLowerCase();
    }

    function makeArray(length) {
        return Array.from(new Array(length), (x,i) => i);
    }
    
    function shuffleArray(a) {
        for (let i = a.length - 1; i > 0; i--) {
            const j = Math.floor(Math.random() * (i + 1));
            [a[i], a[j]] = [a[j], a[i]];
        }
        return a;
    }

    function playListByName(name, create) {
        var app = Application('iTunes'),
            index = app.playlists.name().map(toLower).indexOf(toLower(name));
        if (index === -1) {
            if (create) {
                console.log('Create the "' + name + '" playlist');
                var playlist = app.UserPlaylist().make();
                playlist.name = name;
                return playlist;
            }
            console.log('The "' + name + '"  playlist is not found');
            return;
        } else {
            return app.playlists.at(index);
        }
    }
    
    function clearPlayList(playlist) {
        console.log('Clear the "' + playlist.name() + '" playlist');
        const length = playlist.tracks.length;
        for (let i = 0; i < length; i++) {
            playlist.tracks[0].delete();
        }
    }

    function shufflePlaylist(from_playlist, to_playlist, count) {
        if (!from_playlist) return;
        if (!to_playlist) return;
        var app = Application('iTunes'),
            length = from_playlist.tracks.length,
            shuffle = shuffleArray(makeArray(length)).slice(0, count);
        clearPlayList(to_playlist);
        console.log('Add songs to the "' + to_playlist.name() + '" playlist');
        for (let i in shuffle) {
            from_playlist.tracks[shuffle[i]].duplicate({to: to_playlist});
        }
        console.log('Play');
        app.songRepeat = 'off';
        app.shuffleEnabled = false;
        app.play(to_playlist);
        console.log('Ready');
    }

    shufflePlaylist(playListByName('Random'), 
                    playListByName('Random Shuffle', true), 
                    100);
})();