Close foobar2000 and open user-components\foo_spider_monkey_panel\samples\complete\js\helpers.js in a text editor. Replace the existing _getFiles function on line 260 with this.
function _getFiles(str, exts, newest_first) {
let files = [];
const folders = str.split('|').map((item) => item.trim());
for (const folder of folders) {
if (_isFolder(folder)) {
let e = new Enumerator(fso.GetFolder(folder).Files);
for (; !e.atEnd(); e.moveNext()) {
const path = e.item().Path;
if (!exts || exts.includes(_getExt(path))) {
files.push(path);
}
}
}
}
if (newest_first) {
return _.orderBy(files, (item) => {
return _lastModified(item);
}, 'desc');
} else {
files.srt();
return files;
}
}
You can now open foobar, right click the thumbs panel>Set custom folder and separate multiple folders with a | character. Using $if won't work. If folders don't exist/are empty, they will be ignored.