implement pinch to zoom

node_modules/component-event/index.js

@@ -0,0 +1,35 @@
+var bind = window.addEventListener ? 'addEventListener' : 'attachEvent',
+    unbind = window.removeEventListener ? 'removeEventListener' : 'detachEvent',
+    prefix = bind !== 'addEventListener' ? 'on' : '';
+
+/**
+ * Bind `el` event `type` to `fn`.
+ *
+ * @param {Element} el
+ * @param {String} type
+ * @param {Function} fn
+ * @param {Boolean} capture
+ * @return {Function}
+ * @api public
+ */
+
+exports.bind = function(el, type, fn, capture){
+  el[bind](prefix + type, fn, capture || false);
+  return fn;
+};
+
+/**
+ * Unbind `el` event `type`'s callback `fn`.
+ *
+ * @param {Element} el
+ * @param {String} type
+ * @param {Function} fn
+ * @param {Boolean} capture
+ * @return {Function}
+ * @api public
+ */
+
+exports.unbind = function(el, type, fn, capture){
+  el[unbind](prefix + type, fn, capture || false);
+  return fn;
+};