Prototype of Dart proxies for JS objects.

pkg/element_created/lib/element_created.js

Index: pkg/element_created/lib/element_created.js
diff --git a/pkg/element_created/lib/element_created.js b/pkg/element_created/lib/element_created.js
new file mode 100644
index 0000000000000000000000000000000000000000..243794501d9946bdf2fb2d4a541e1cd74f2bb89d
--- /dev/null
+++ b/pkg/element_created/lib/element_created.js
@@ -0,0 +1,67 @@
+(function (doc) {
+
+  var originalRegisterElement = document.registerElement;
+  if (!originalRegisterElement) {
+    throw new Error('document.registerElement is not present.');
+  }
+
+  function registerElement(name, options) {
+    var newOptions = Object.create(options);
+    for (var attr in options) {
+      if (options.hasOwnProperty(attr)) {
+        newOptions[attr] = options[attr];
+      }
+    }
+
+    var originalCreated = newOptions.prototype.createdCallback;
+
+    newOptions.prototype.createdCallback = function() {
+      originalCreated.call(this);
+
+      var key = getTagKey(this.tagName, this.getAttribute('is'));
+      var watchers = createdWatchers[key];
+      if (!watchers) {
+        return;
+      }
+      for (var i = 0, w; (w = watchers[i]); i++) {
+        invokeWatcher(this, w);
+      }
+    };
+
+    return originalRegisterElement.call(doc, name, newOptions);
+  }
+
+  function invokeWatcher(node, watcher) {
+    if (watcher.createdCallback) {
+      watcher.createdCallback.call(node);
+    }
+  }
+
+  // Unique key for the tagName & extends combo
+  function getTagKey(tagName, isTag) {
+    if (isTag) {
+      // '.' is a reserved character for XML names, so safe to use.
+      return tagName.toUpperCase() + '.' + isTag.toUpperCase();
+    }
+    return tagName.toUpperCase();
+  }
+
+  var createdWatchers = {};
+
+
+  function registerElementCreatedWatcher(name, options) {
+    if (!options) return;
+
+    var key = getTagKey(name, options.extends);
+    if (key in createdWatchers) {
+      createdWatchers[key].push(options);
+    } else {
+      createdWatchers[key] = [options];
+    }
+  }
+
+
+
+  doc.registerElementCreatedWatcher = registerElementCreatedWatcher;
+  doc.registerElement = registerElement;
+})(document);