npm install, then:
npx rollup --config
Then change the following in node_modules/sidebar-v2/js/ol3-sidebar.mjs:
if ('inherits' in ol) {
Sidebar.prototype = Object.create(Control.prototype);
Sidebar.prototype.constructor = Sidebar;
} else {
Sidebar.prototype = Object.create(Control.prototype);
Sidebar.prototype.constructor = Sidebar;
}
change to:
Sidebar.prototype = Object.create(Control.prototype);
Sidebar.prototype.constructor = Sidebar;
then npm run