What is a memory leak: jQuery supports chaining/fluid style. In order to make it work it keeps references to other jQuery objects in a .prevObject property
const $leaky = $('<div><span>LEAK</span></div>').find('span').parent().empty(); // [ <div></div> ]
// <span> has been removed from the <div> and we expect it to be garbage collected
// Oh no! It's still here!
console.log( $leaky.prevObject ); // [ <span>LEAK</span> ]
// And we can "end" the chaining and get it back even if it's already detached
console.log( $leaky.end() ); // [ <span>LEAK</span> ]How to fix: Delete the .prevObject or create a new jQuery object from this one
const $clean = $(
$('<div><span>LEAK</span></div>').find('span').parent().empty()
); // [ <div></div> ]
// <span> has been removed from the <div> and we expect it to be garbage collected
// Yup, there's no more references and it can be GC'ed.
console.log( $clean.prevObject ); // undefined
console.log( $clean.end() ); // [ /* an empty jQuery object */ ]