if(...){
 newa.playlist[t].num = $('.tagEditor .num').val();
 newa.playlist[t].name = $('.tagEditor .name').val();
 newa.playlist[t].artist = $('.tagEditor .artist').val();
 newa.playlist[t].album = $('.tagEditor .album').val();
 newa.playlist[t].date = $('.tagEditor .date').val();
}else if(...){
 newp.playlist[t].num = $('.tagEditor .num').val();
 newp.playlist[t].name = $('.tagEditor .name').val();
 newp.playlist[t].artist = $('.tagEditor .artist').val();
 newp.playlist[t].album = $('.tagEditor .album').val();
 newp.playlist[t].date = $('.tagEditor .date').val();
}else if(...){
 newv.playlist[t].num = $('.tagEditor .num').val();
 newv.playlist[t].name = $('.tagEditor .name').val();
 newv.playlist[t].artist = $('.tagEditor .artist').val();
 newv.playlist[t].album = $('.tagEditor .album').val();
 newv.playlist[t].date = $('.tagEditor .date').val();
}

var fields = ['num', 'name', 'artist', 'album', 'date'],
    obj = newv;

if(...) obj = newa;
if(...) obj = newp;

for(var i in fields) {
  obj.playlist[t][fields[i]] = $('.tagEditor .' + fields[i]).val();
}

for (var i in newa.playlist[t])
{
newa.playlist[t][i] = $('.tagEditor .' + i).val();
}

$.extractMetaData = (function (names/**array*/){
    return function (target/**jQuery|String*/){
        var data = {};
        $.each(names, function (i, name) {
            data[name] = $('.' + name, target).val();
        });
        return data;
    };
})('num name artist album date'.split(' '));

// Usage
newa.playlist[t] = $.extractMetaData('.tagEditor');

if(...){
    with( newa.playlist[t]){
        num = $('.tagEditor .num').val();
        name = $('.tagEditor .name').val();
        artist = $('.tagEditor .artist').val();
        album = $('.tagEditor .album').val();
        date = $('.tagEditor .date').val();
    }
}else if(...){
    with( newp.playlist[t]){
    ...

var X;
if(...){
    X = newa.playlist[t];
    X.num = $('.tagEditor .num').val();
    X.name = $('.tagEditor .name').val();
    X.artist = $('.tagEditor .artist').val();
    X.album = $('.tagEditor .album').val();
    X.date = $('.tagEditor .date').val();
}else if(...){
    X = newp.playlist[t];
    ...

function xx(zz)
 {
   zz.num = $('.tagEditor .num').val();
   zz.name = $('.tagEditor .name').val();
   zz.artist = $('.tagEditor .artist').val();
   zz.album = $('.tagEditor .album').val();
   zz.date = $('.tagEditor .date').val();
 }

 if (..) {
   xx(newa.playlist[t]);
 }
 else if (..)
 {
   xx(newv.playlist[t]);
 }
 else
   xx(newp.playlist[t]);

const props = [
    'num',
    'name',
    'artist',
    'album',
    'date'
]

function getval(element, t){
    for (const prop of props){
        element.playlist[t][prop] = $(`.tagEditor ${prop}`).val()
    }
}

if(...){
    getval(newa)
}else if(...){
    getval(newp)
}else if(...){
    getval(newv)
}