Function dragOverValid

plugins/Swap/Swap.js:20–41

({ completed, target, onMove, activeSortable, changed, cancel })

			lastSwapEl = dragEl;
		},
		dragOverValid({ completed, target, onMove, activeSortable, changed, cancel }) {
			if (!activeSortable.options.swap) return;
			let el = this.sortable.el,
				options = this.options;
			if (target && target !== el) {
				let prevSwapEl = lastSwapEl;
				if (onMove(target) !== false) {
					toggleClass(target, options.swapClass, true);
					lastSwapEl = target;
				} else {
					lastSwapEl = null;
				}

				if (prevSwapEl && prevSwapEl !== lastSwapEl) {
					toggleClass(prevSwapEl, options.swapClass, false);
				}
			}
			changed();

			completed(true);
			cancel();
		},
		drop({ activeSortable, putSortable, dragEl }) {
			let toSortable = (putSortable || this.sortable);
			let options = this.options;