fix(events): fix triggering panzoomend for one pointer event

Fixes gh-428

src/panzoom.ts

@@ -435,17 +435,18 @@ function Panzoom(
   }
 
   function handleUp(event: PointerEvent) {
+    // Don't call panzoomend when panning with 2 touches
+    // until both touches end
+    if (pointers.length === 1) {
+      trigger('panzoomend', { x, y, scale }, options)
+    }
     // Note: don't remove all pointers
     // Can restart without having to reinitiate all of them
     // Remove the pointer regardless of the isPanning state
     removePointer(pointers, event)
     if (!isPanning) {
       return
     }
-    // Only call panzoomend once
-    if (pointers.length === 1) {
-      trigger('panzoomend', { x, y, scale }, options)
-    }
     isPanning = false
     origX = origY = startClientX = startClientY = undefined
   }

test/unit/panzoom.test.ts

@@ -71,10 +71,19 @@ describe('Panzoom', () => {
     }
     const panzoom = Panzoom(div)
     assert(Object.keys(events).length > 0)
+    const endListener = () => {
+      console.log('panzoomend called')
+      assert.ok('panzoomend called on pan')
+    }
+    div.addEventListener('panzoomend', endListener)
+    div.dispatchEvent(new PointerEvent('pointerdown'))
+    document.dispatchEvent(new PointerEvent('pointerup'))
     panzoom.destroy()
+    div.removeEventListener('panzoomend', endListener)
     assert(Object.keys(events).length === 0)
     Element.prototype.addEventListener = addEvent
     Element.prototype.removeEventListener = removeEvent
+    document.body.removeChild(div)
   })
   it('sets the expected transform-origin on SVG', () => {
     const elem = document.createElementNS('http://www.w3.org/2000/svg', 'g')