Use .closest() for the Nearest Match
Efficient for single matches: When you only need the nearest matching ancestor or element, .closest() is more efficient because it stops traversing as soon as it finds a match. This makes it more performant when you are only looking for one ancestor.
Example:
// Finds the closest ancestor with class 'form' or the element itself
$(this).closest('.form');
This will stop as soon as it finds the first ancestor (or the element itself) with the class .form, which reduces unnecessary traversals compared to .parents().
Use .parents() for Multiple Matches
Use .parents() when you want to collect all ancestors that match a selector, not just the closest one. This is useful when you need to traverse up the entire DOM tree and gather multiple matches.
Example:
// Finds all ancestors with class 'section'
$(this).parents('.section');
Unlike .closest(), which stops after finding the first matching ancestor, .parents() returns all matching ancestors.
Limit the Context for Better Performance
Both .closest() and .parents() can be costly in terms of performance if the DOM tree is large, especially if you don't limit their scope.
Limit the selector: Be specific with your selectors to ensure that jQuery only searches the necessary parts of the DOM.
Example:
// Limiting the context to a specific parent div
$(this).closest('div.container .header');
Limit the search context: Use .parents() in a more constrained way by narrowing down the context or parent element from which to start the traversal.
// Limiting the search to a particular part of the DOM
$('#specific-parent').parents('.ancestor');
