🐞 check for browser window #49 #85 #86

Addresses `this = window` mismatch with Webpack, Parcel, Gatsby.

js/dragger.js

@@ -6,30 +6,34 @@
  // module definition
  if ( typeof module == 'object' && module.exports ) {
  // CommonJS
- module.exports = factory( root );
+ module.exports = factory();
  } else {
  // browser global
- root.Zdog.Dragger = factory( root );
+ root.Zdog.Dragger = factory();
  }
-}( this, function factory( window ) {
+}( this, function factory() {
 
 // quick & dirty drag event stuff
 // messes up if multiple pointers/touches
 
+// check for browser window #85
+var hasWindow = typeof window != 'undefined';
 // event support, default to mouse events
 var downEvent = 'mousedown';
 var moveEvent = 'mousemove';
 var upEvent = 'mouseup';
-if ( window.PointerEvent ) {
- // PointerEvent, Chrome
- downEvent = 'pointerdown';
- moveEvent = 'pointermove';
- upEvent = 'pointerup';
-} else if ( 'ontouchstart' in window ) {
- // Touch Events, iOS Safari
- downEvent = 'touchstart';
- moveEvent = 'touchmove';
- upEvent = 'touchend';
+if ( hasWindow ) {
+ if ( window.PointerEvent ) {
+ // PointerEvent, Chrome
+ downEvent = 'pointerdown';
+ moveEvent = 'pointermove';
+ upEvent = 'pointerup';
+ } else if ( 'ontouchstart' in window ) {
+ // Touch Events, iOS Safari
+ downEvent = 'touchstart';
+ moveEvent = 'touchmove';
+ upEvent = 'touchend';
+ }
 }
 
 function noop() {}
@@ -84,8 +88,10 @@ Dragger.prototype.dragStart = function( event, pointer ) {
  event.preventDefault();
  this.dragStartX = pointer.pageX;
  this.dragStartY = pointer.pageY;
- window.addEventListener( moveEvent, this );
- window.addEventListener( upEvent, this );
+ if ( hasWindow ) {
+ window.addEventListener( moveEvent, this );
+ window.addEventListener( upEvent, this );
+ }
  this.onDragStart( pointer );
 };