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1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 /// Provides support for associating a Dart type for Javascript Custom Elements. | 5 /// Provides support for associating a Dart type for Javascript Custom Elements. |
6 /// This will not work unless `dart_support.js` is loaded. | 6 /// This will not work unless `dart_support.js` is loaded. |
7 library web_components.interop; | 7 library web_components.interop; |
8 | 8 |
9 import 'dart:async' show Stream, StreamController; | |
10 import 'dart:html' show document, Element; | 9 import 'dart:html' show document, Element; |
11 import 'dart:js' show JsObject, JsFunction; | 10 import 'dart:js' show JsObject, JsFunction; |
12 | 11 |
13 final _doc = new JsObject.fromBrowserObject(document); | 12 final _doc = new JsObject.fromBrowserObject(document); |
14 | 13 |
15 /// Returns whether [registerDartType] is supported, which requires to have | 14 /// Returns whether [registerDartType] is supported, which requires to have |
16 /// `dart_support.js` already loaded in the page. | 15 /// `dart_support.js` already loaded in the page. |
17 bool get isSupported => _doc.hasProperty('_registerDartTypeUpgrader'); | 16 bool get isSupported => _doc.hasProperty('_registerDartTypeUpgrader'); |
18 | 17 |
19 /// Watches when Javascript custom elements named [tagName] are created and | 18 /// Watches when Javascript custom elements named [tagName] are created and |
20 /// associates the created element with the given [dartType]. Only one Dart type | 19 /// associates the created element with the given [dartType]. Only one Dart type |
21 /// can be registered for a given tag name. | 20 /// can be registered for a given tag name. |
22 void registerDartType(String tagName, Type dartType, {String extendsTag}) { | 21 void registerDartType(String tagName, Type dartType, {String extendsTag}) { |
23 if (!isSupported) { | 22 if (!isSupported) { |
24 throw new UnsupportedError("Couldn't find " | 23 throw new UnsupportedError("Couldn't find " |
25 "`document._registerDartTypeUpgrader`. Please make sure that " | 24 "`document._registerDartTypeUpgrader`. Please make sure that " |
26 "`packages/web_components/interop_support.html` is loaded and " | 25 "`packages/web_components/interop_support.html` is loaded and " |
27 "available before calling this function."); | 26 "available before calling this function."); |
28 } | 27 } |
29 | 28 |
30 var upgrader = document.createElementUpgrader( | 29 var upgrader = |
31 dartType, extendsTag: extendsTag); | 30 document.createElementUpgrader(dartType, extendsTag: extendsTag); |
32 | 31 |
33 // Unfortunately the dart:html upgrader will throw on an already-upgraded | 32 // Unfortunately the dart:html upgrader will throw on an already-upgraded |
34 // element, so we need to duplicate the type check to prevent that. | 33 // element, so we need to duplicate the type check to prevent that. |
35 // An element can be upgraded twice if it extends another element and calls | 34 // An element can be upgraded twice if it extends another element and calls |
36 // createdCallback on the superclass. Since that's a valid use case we must | 35 // createdCallback on the superclass. Since that's a valid use case we must |
37 // wrap at both levels, and guard against it here. | 36 // wrap at both levels, and guard against it here. |
38 upgradeElement(e) { | 37 upgradeElement(e) { |
39 if (e.runtimeType != dartType) upgrader.upgrade(e); | 38 if (e.runtimeType != dartType) upgrader.upgrade(e); |
40 } | 39 } |
41 | 40 |
42 _doc.callMethod('_registerDartTypeUpgrader', [tagName, upgradeElement]); | 41 _doc.callMethod('_registerDartTypeUpgrader', [tagName, upgradeElement]); |
43 } | 42 } |
44 | 43 |
45 /// This function is mainly used to save resources. By default, we save a log of | 44 /// This function is mainly used to save resources. By default, we save a log of |
46 /// elements that are created but have no Dart type associated with them. This | 45 /// elements that are created but have no Dart type associated with them. This |
47 /// is so we can upgrade them as soon as [registerDartType] is invoked. This | 46 /// is so we can upgrade them as soon as [registerDartType] is invoked. This |
48 /// function can be called to indicate that we no longer are interested in | 47 /// function can be called to indicate that we no longer are interested in |
49 /// logging element creations and that it is sufficient to only upgrade new | 48 /// logging element creations and that it is sufficient to only upgrade new |
50 /// elements as they are being created. Typically this is called after the last | 49 /// elements as they are being created. Typically this is called after the last |
51 /// call to [registerDartType] or as soon as you know that no element will be | 50 /// call to [registerDartType] or as soon as you know that no element will be |
52 /// created until the call to [registerDartType] is made. | 51 /// created until the call to [registerDartType] is made. |
53 void onlyUpgradeNewElements() => _doc.callMethod('_onlyUpgradeNewElements'); | 52 void onlyUpgradeNewElements() => _doc.callMethod('_onlyUpgradeNewElements'); |
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