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	<li>Item 1</li>
	<li class="stop-here">Item 2</li>
	<li>Item 3</li>
	<li class="skip-me">Item 4</li>
	<li id="find-me">Item 5</li>
	<li class="skip-me">Item 6</li>
	<li>Item 7</li>
	<li class="stop-here">Item 8</li>
	<li>Item 9</li>




 * Get previous sibling of an element that matches a test condition
 * (c) 2021 Chris Ferdinandi, MIT License,
 * @param  {Node}     elem     The element
 * @param  {Function} callback The test condition
 * @return {Node}              The sibling
function getPreviousSibling (elem, callback) {

	// Get the next sibling element
	let sibling = elem.previousElementSibling;

	// If there's no callback, return the first sibling
	if (!callback || typeof callback !== 'function') return sibling;

	// If the sibling matches our test condition, use it
	// If not, jump to the next sibling and continue the loop
	let index = 0;
	while (sibling) {
		if (callback(sibling, index, elem)) return sibling;
		sibling = sibling.previousElementSibling;


let findMe = document.querySelector('#find-me');

// Returns '<li class="skip-me">Item 4</li>'
let prev = getPreviousSibling(findMe);

// Returns '<li class="stop-here">Item 2</li>'
let prevStop = getPreviousSibling(findMe, function (sibling) {
	return sibling.matches('.stop-here');

// Returns '<li>Item 3</li>'
let prevSkip = getPreviousSibling(findMe, function (sibling) {
	return !sibling.matches('.skip-me');

console.log('prev', prev);
console.log('prevStop', prevStop);
console.log('prevSkip', prevSkip);