Add option to only apply delay on touch events (#1482)

README.md

@@ -84,6 +84,7 @@ var sortable = new Sortable(el, {
 	group: "name",  // or { name: "...", pull: [true, false, 'clone', array], put: [true, false, array] }
 	sort: true,  // sorting inside list
 	delay: 0, // time in milliseconds to define when the sorting should start
+	delayOnTouchOnly: false, // only delay if user is using touch
 	touchStartThreshold: 0, // px, how many pixels the point should move before cancelling a delayed drag event
 	disabled: false, // Disables the sortable if set to true.
 	store: null,  // @see Store
@@ -247,6 +248,13 @@ Demo: https://jsbin.com/zosiwah/edit?js,output
 ---
 
 
+#### `delayOnTouchOnly` option
+Whether or not the delay should be applied only if the user is using touch (eg. on a mobile device). No delay will be applied in any other case. Defaults to `false`.
+
+
+---
+
+
 #### `swapThreshold` option
 Percentage of the target that the swap zone will take up, as a float between `0` and `1`.
 

Sortable.js

@@ -529,6 +529,7 @@
 			dragoverBubble: false,
 			dataIdAttr: 'data-id',
 			delay: 0,
+			delayOnTouchOnly: false,
 			touchStartThreshold: parseInt(window.devicePixelRatio, 10) || 1,
 			forceFallback: false,
 			fallbackClass: 'sortable-fallback',
@@ -819,7 +820,7 @@
 				}
 
 				// Delay is impossible for native DnD in Edge or IE
-				if (options.delay && (!this.nativeDraggable || !(Edge || IE11OrLess))) {
+				if (options.delay && (options.delayOnTouchOnly ? touch : true) && (!this.nativeDraggable || !(Edge || IE11OrLess))) {
 					// If the user moves the pointer or let go the click or touch
 					// before the delay has been reached:
 					// disable the delayed drag