Allow for use in old IE by providing a non-getter API for size of poi…

…ntermap

src/pointermap.js

@@ -5,66 +5,59 @@
  */
 
 /**
- * This module implements an ordered list of pointer states
- * Each pointer object here has two properties:
- *  - id: the id of the pointer
- *  - event: the source event of the pointer, complete with positions
- *
- * The ordering of the pointers is from oldest pointer to youngest pointer,
- * which allows for multi-pointer gestures to not rely on the actual ids
- * imported from the source events.
- *
- * Any operation that needs to store state information about pointers can hang
- * objects off of the pointer in the pointermap. This information will be
- * preserved until the pointer is removed from the pointermap.
+ * This module implements an map of pointer states
  */
 (function(scope) {
+  var USE_MAP = window.Map && window.Map.prototype.forEach;
+  var POINTERS_FN = function(){ return this.size; };
   function PointerMap() {
-    this.ids = [];
-    this.pointers = [];
-  };
+    if (USE_MAP) {
+      var m = new Map();
+      m.pointers = POINTERS_FN;
+      return m;
+    } else {
+      this.keys = [];
+      this.values = [];
+    }
+  }
 
   PointerMap.prototype = {
     set: function(inId, inEvent) {
-      var i = this.ids.indexOf(inId);
+      var i = this.keys.indexOf(inId);
       if (i > -1) {
-        this.pointers[i] = inEvent;
+        this.values[i] = inEvent;
       } else {
-        this.ids.push(inId);
-        this.pointers.push(inEvent);
+        this.keys.push(inId);
+        this.values.push(inEvent);
       }
     },
     has: function(inId) {
-      return this.ids.indexOf(inId) > -1;
+      return this.keys.indexOf(inId) > -1;
     },
     'delete': function(inId) {
-      var i = this.ids.indexOf(inId);
+      var i = this.keys.indexOf(inId);
       if (i > -1) {
-        this.ids.splice(i, 1);
-        this.pointers.splice(i, 1);
+        this.keys.splice(i, 1);
+        this.values.splice(i, 1);
       }
     },
     get: function(inId) {
-      var i = this.ids.indexOf(inId);
-      return this.pointers[i];
-    },
-    get size() {
-      return this.pointers.length;
+      var i = this.keys.indexOf(inId);
+      return this.values[i];
     },
     clear: function() {
-      this.ids.length = 0;
-      this.pointers.length = 0;
+      this.keys.length = 0;
+      this.values.length = 0;
     },
     forEach: function(callback, thisArg) {
-      this.ids.forEach(function(id, i) {
-        callback.call(thisArg, id, this.pointers[i], this);
+      this.keys.forEach(function(id, i) {
+        callback.call(thisArg, id, this.values[i], this);
       }, this);
+    },
+    pointers: function() {
+      return this.keys.length;
     }
   };
 
-  if (window.Map && Map.prototype.forEach) {
-    scope.PointerMap = Map;
-  } else {
-    scope.PointerMap = PointerMap;
-  }
+  scope.PointerMap = PointerMap;
 })(window.PointerEventsPolyfill);

src/touch.js

@@ -104,7 +104,7 @@
     },
     setPrimaryTouch: function(inTouch) {
       // set primary touch if there no pointers, or the only pointer is the mouse
-      if (pointermap.size == 0 || (pointermap.size == 1 && pointermap.has(1))) {
+      if (pointermap.pointers() === 0 || (pointermap.pointers() === 1 && pointermap.has(1))) {
         this.firstTouch = inTouch.identifier;
         this.firstXY = {X: inTouch.clientX, Y: inTouch.clientY};
         this.scrolling = false;
@@ -198,9 +198,9 @@
     // pointercancel for this "abandoned" touch
     vacuumTouches: function(inEvent) {
       var tl = inEvent.touches;
-      // pointermap.size should be < tl.length here, as the touchstart has not
+      // pointermap.pointers() should be < tl.length here, as the touchstart has not
       // been processed yet.
-      if (pointermap.size >= tl.length) {
+      if (pointermap.pointers() >= tl.length) {
         var d = [];
         pointermap.forEach(function(key, value) {
           // Never remove pointerId == 1, which is mouse.

tests/pointermap.js

@@ -6,7 +6,7 @@ suite('PointerMap', function() {
       'get',
       'has',
       'delete',
-      'size',
+      'pointers',
       'clear',
       'forEach'
     ];
@@ -16,49 +16,49 @@ suite('PointerMap', function() {
     });
   });
   test('PointerMap .set', function() {
-    var p = new PointerMap;
+    var p = new PointerMap();
     p.set(1, true);
     if (PointerMap !== window.Map) {
-      expect(p.ids).to.have.length(1);
-      expect(p.pointers).to.have.length(1);
+      expect(p.keys).to.have.length(1);
+      expect(p.values).to.have.length(1);
     }
-    expect(p.size).to.equal(1);
+    expect(p.pointers()).to.equal(1);
   });
   test('PointerMap .get', function() {
-    var p = new PointerMap;
+    var p = new PointerMap();
   });
-  test('PointerMap .size', function() {
-    var p = new PointerMap;
-    expect(p.size).not.to.be.a('function');
-    expect(p.size).to.equal(0);
+  test('PointerMap .pointers', function() {
+    var p = new PointerMap();
+    expect(p.pointers).to.be.a('function');
+    expect(p.pointers()).to.equal(0);
     p.set(1, true);
-    expect(p.size).to.equal(1);
+    expect(p.pointers()).to.equal(1);
     p.set(1, false);
-    expect(p.size).to.equal(1);
+    expect(p.pointers()).to.equal(1);
   });
   test('PointerMap .has', function() {
-    var p = new PointerMap;
+    var p = new PointerMap();
     p.set(1, true);
     expect(p.has(1)).to.equal(true);
     expect(p.has(0)).to.equal(false);
   });
   test('PointerMap .delete', function() {
-    var p = new PointerMap;
+    var p = new PointerMap();
     p.set(1, true);
     p.set(2, false);
-    expect(p.size).to.equal(2);
+    expect(p.pointers()).to.equal(2);
     p.delete(1);
-    expect(p.size).to.equal(1);
+    expect(p.pointers()).to.equal(1);
     expect(p.get(2)).to.equal(false);
   });
   test('PointerMap .clear', function() {
-    var p = new PointerMap;
+    var p = new PointerMap();
     p.set(1, true);
     p.clear();
-    expect(p.size).to.equal(0);
+    expect(p.pointers()).to.equal(0);
   });
   test('PointerMap .forEach', function() {
-    var p = new PointerMap;
+    var p = new PointerMap();
     p.set(1, true);
     p.set(2, false);
     p.set(3, {});