1 files changed, 90 insertions, 0 deletions
diff --git a/library/Sortable/plugins/Swap/Swap.js b/library/Sortable/plugins/Swap/Swap.js
new file mode 100644
index 000000000..3f0feb7dc
--- /dev/null
+++ b/library/Sortable/plugins/Swap/Swap.js
@@ -0,0 +1,90 @@
+import {
+	toggleClass,
+	index
+} from '../../src/utils.js';
+
+let lastSwapEl;
+
+
+function SwapPlugin() {
+	function Swap() {
+		this.defaults = {
+			swapClass: 'sortable-swap-highlight'
+		};
+	}
+
+	Swap.prototype = {
+		dragStart({ dragEl }) {
+			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;
+			lastSwapEl && toggleClass(lastSwapEl, options.swapClass, false);
+			if (lastSwapEl && (options.swap || putSortable && putSortable.options.swap)) {
+				if (dragEl !== lastSwapEl) {
+					toSortable.captureAnimationState();
+					if (toSortable !== activeSortable) activeSortable.captureAnimationState();
+					swapNodes(dragEl, lastSwapEl);
+
+					toSortable.animateAll();
+					if (toSortable !== activeSortable) activeSortable.animateAll();
+				}
+			}
+		},
+		nulling() {
+			lastSwapEl = null;
+		}
+	};
+
+	return Object.assign(Swap, {
+		pluginName: 'swap',
+		eventProperties() {
+			return {
+				swapItem: lastSwapEl
+			};
+		}
+	});
+}
+
+
+function swapNodes(n1, n2) {
+	let p1 = n1.parentNode,
+		p2 = n2.parentNode,
+		i1, i2;
+
+	if (!p1 || !p2 || p1.isEqualNode(n2) || p2.isEqualNode(n1)) return;
+
+	i1 = index(n1);
+	i2 = index(n2);
+
+	if (p1.isEqualNode(p2) && i1 < i2) {
+		i2++;
+	}
+	p1.insertBefore(n2, p1.children[i1]);
+	p2.insertBefore(n1, p2.children[i2]);
+}
+
+export default SwapPlugin;