getUniqueSelector — Return a unique selector for a specific element (151 bytes minified, 144 bytes gzipped)

getUniqueSelector.js

/** Return a unique selector for a specific element. */
let getUniqueSelector = (/** @type {Element} */ element) => {
	/** Unique selector for this element */
	let selector = ''

	/** @type {Element} */
	let parent

	/** @type {number} */
	let nth

	while (parent = element.parentElement) {
		for (nth = 1; element = element.previousElementSibling; ++nth);

		selector = ' > :nth-child(' + nth + ')' + selector

		element = parent
	}

	return ':root' + selector
}