TPE DOM/Custom elements

Introduction

This project is to enable web authors to define and use new types of DOM elements in a document.

References:

• Custom Elements spec
• whatwg html wiki
• whatwg dom wiki
• blink-dev intent-to-implement
• Blink bugs
  • https://bugs.chromium.org/p/chromium/issues/detail?id=594918
• Safari bugs
  • https://bugs.webkit.org/show_bug.cgi?id=154907
  • https://bugs.webkit.org/show_bug.cgi?id=150225
  • https://bugs.webkit.org/show_bug.cgi?id=155108

Taipei Main Members

Engineers: Edgar Chen (main contact), John Dai

Meeting Minutes

Sync-up minutes

Roadmap

[Stage 1]

1. Remove support of SVG-based custom element.
   • Bug: 1274505
2. Window interface
   • Separate control preference
   • Move mRegistry from document to window.customElements
   • Bugs: 1275833, 1275832, 1275838, 1275839
3. HTMLElement constructor
   • Support using ES6 classes
   • Construction stack
   • Bug: 1274159
4. Document interface
   • createElement, createElementNS
   • Bug: 1276579
5. window.customElements.define
   • Bug: 1275835

[Stage 2] <We are here - Stretch goal: 2017 Q3 Stage2.1 & 2.2>

1. custom element upgrade reactions stack/queue
   • Upgrade reaction
2. Algorithm of creating an element
   • Spec: https://dom.spec.whatwg.org/#concept-create-element
   • Revise consumers (createElement[NS] and HTML parser accordingly
     • HTML parser: https://dxr.mozilla.org/mozilla-central/source/parser/html/nsHtml5TreeOperation.cpp#335

[Stage 3] <We are here - Stretch goal: 2017 Q3 Stage2.1 & 2.2>

1. Callback reaction queue
2. Lifecycle callbacks
   • • sProcessingStack
     • EnqueueLifecycleCallback
   • connectedCallback
   • disconnectedCallback
   • attributeChangedCallback

[Stage 4]

1. Mutation algorithms (Shadow dom)
   • Spec:
     • https://dom.spec.whatwg.org/#mutation-algorithms
     • https://w3c.github.io/webcomponents/spec/custom/#dom-mutation-algorithms
2. CSS :define
3. Performance
4. Web-platform-tests
   • https://bugzilla.mozilla.org/show_bug.cgi?id=1234886

Project Dashboard

Meta Bugs

Full Query

ID	Summary	Priority	Status
889230	[meta] Implement Custom Elements (from Web Components)	P3	RESOLVED

1 Total; 0 Open (0%); 1 Resolved (100%); 0 Verified (0%);

1st Impl. Shipping Blocker: Stage_2 Bugs & Progress (IN PROGRESS)

Full Query

ID	Summary	Status	Target milestone	Resolution	Assigned to	Depends on	Blocks
1287348	Implement construction stack for upgrading an element	RESOLVED	---	DUPLICATE	Edgar Chen [:edgar]	1274159	889230
1299363	Implement custom element v1 upgrade algorithm	RESOLVED	mozilla57	FIXED	John Dai[:jdai]	1325279, 1353647, 1359346	889230, 1301024, 1319342, 1331334, 1378079
1301024	Creating an custom element via createElement/createElementNS should call constructor or run upgrade steps	RESOLVED	mozilla58	FIXED	John Dai[:jdai]	1274159, 1299363, 1354013, 1407669, 1411088	889230, 1331334, 1396761
1309147	Add [CEReactions] to support custom element reactions	RESOLVED	mozilla55	FIXED	John Dai[:jdai]	1347446	889230, 1315885, 1340027
1309176	Add stack-of-queues system for custom element reaction	RESOLVED	---	DUPLICATE	John Dai[:jdai]		889230
1309184	Implement upgrade reaction for custom element reactions	RESOLVED	mozilla53	FIXED	John Dai[:jdai]		889230, 1319342, 1325279
1319342	Cloning a node runs concept-create-element steps with synchronous-custom-elements-flag unset which enqueues an upgrade reaction	RESOLVED	mozilla58	FIXED	John Dai[:jdai]	1299363, 1309184	889230
1325279	Put the reaction queue in CustomElementData structure instead of using a map	RESOLVED	mozilla55	FIXED	Edgar Chen [:edgar]	1309184, 1359346	889230, 1299363, 1315885
1347446	Move custom element reactions stack to DocGroup	RESOLVED	mozilla55	FIXED	John Dai[:jdai]	1350960	889230, 1309147, 1315885
1354013	Creating customized built-in elements without relevant definitions registered first shouldn't throw NotFoundError	RESOLVED	mozilla55	FIXED	Edgar Chen [:edgar]		889230, 1301024
1357002	Calling document.createElement() with a second arg that includes "is" should not have noticeable slowdown when custom elements feature is pref-ed off	RESOLVED	mozilla55	FIXED	Edgar Chen [:edgar]		889230
1359346	Implement custom element state	RESOLVED	mozilla55	FIXED	Edgar Chen [:edgar]		889230, 1299363, 1325279
1378079	Creating an custom element from parser will synchronously call constructor	RESOLVED	mozilla58	FIXED	Jessica Jong [:jessica] (inactive)	1299363, 1411088, 1510114	889230, 1418002
1406297	Document.createElement must report an exception which is user defined thrown by a custom element constructor	RESOLVED	mozilla58	FIXED	John Dai[:jdai]		889230
1406325	Custom element clone node without definition should put into candidate map in order to upgrade later	RESOLVED	mozilla59	FIXED	John Dai[:jdai]		889230

15 Total; 0 Open (0%); 15 Resolved (100%); 0 Verified (0%);

1st Impl. Shipping Blocker: Performance issues (INPROGRESS)

Full Query

ID	Summary	Status	Target milestone	Resolution	Assigned to	Depends on	Blocks
1356761	Find a better capacity for custom element reactions stack and queues	RESOLVED	mozilla62	FIXED	Olli Pettay [:smaug][bugs@pettay.fi]		1396567
1392970	Consider having a reference of the CustomElementDefinition in the custom element itself	RESOLVED	mozilla58	FIXED	Jessica Jong [:jessica] (inactive)		889230, 1396567, 1408828, 1410790
1392974	[CEReactions] operations should not cause noticeable slowdown if the documents don't have any custom element when custom element feature is enabled	RESOLVED	---	FIXED	Edgar Chen [:edgar]	1421544, 1422197	1396567, 1410536
1396573	When custom elements preference is on, creating a non-custom element via document.createElement() shouldn't have a noticeable slowdown	RESOLVED	---	FIXED	Edgar Chen [:edgar]	1419643	1396567
1396575	Track performance for creating an autonomous custom elements which doesn't match CE definition	RESOLVED	---	FIXED		1430951	1396567
1410536	Enabling the dom.webcomponents.customelements.enabled pref causes some talos regressions (dromaeo_dom, maybe tabpaint)	RESOLVED	---	FIXED	Edgar Chen [:edgar]	1392974	889230, 1396567, 1406825
1414178	Find a better way instead of iterate the candidates array and remove the element from the array	RESOLVED	---	DUPLICATE			1396567
1419643	Do not need to look up custom elements definition for a non-custom element	RESOLVED	mozilla59	FIXED	Edgar Chen [:edgar]		1396567, 1396573
1419660	Track performance for creating a built-in custom elements doesn't match CE definition	RESOLVED	---	DUPLICATE			1396567
1419661	When custom elements preference is on, createElement with define() call and it'll run upgrade which is much slower than what we have now	RESOLVED	mozilla63	FIXED	Olli Pettay [:smaug][bugs@pettay.fi]	1420178, 1428784, 1440382, 1469446, 1470191	1396567
1420377	Avoid atomize 'is' value twice when the custom element is created from parser	RESOLVED	mozilla59	FIXED	Edgar Chen [:edgar]		1396567
1430951	Avoid element name atomizing to improve performance of LookupCustomElementDefinition	RESOLVED	mozilla60	FIXED	Edgar Chen [:edgar]		1396567, 1396575

12 Total; 0 Open (0%); 12 Resolved (100%); 0 Verified (0%);

Post 1st Ship: Stage_4 Bugs & Progress (BACKLOG)

Full Query

ID	Summary	Status	Target milestone	Resolution	Assigned to	Depends on	Blocks
1326028	customElements.define must upgrade custom element in shadow-including tree order	RESOLVED	mozilla61	FIXED	Blake Kaplan (:mrbkap) (inactive)		889230, 1419323
1331334	Implement :defined pseudo-class for custom elements	RESOLVED	mozilla63	FIXED	Olli Pettay [:smaug][bugs@pettay.fi]	1299363, 1301024, 1417829	889230, 1471871
1331341	Enqueue custom element upgrade/callbacks reactions in shadow-including tree order when inserting/removing a node	RESOLVED	---	DUPLICATE			889230

3 Total; 0 Open (0%); 3 Resolved (100%); 0 Verified (0%);

What Have Been DONE

1st Impl. Shipping Blocker: Stage_1 Bugs & Progress (DONE)

Full Query

ID	Summary	Status	Target milestone	Resolution	Assigned to	Depends on	Blocks
1274159	Add [HTMLConstructor] to support custom element feature	RESOLVED	mozilla53	FIXED	Edgar Chen [:edgar]	1275835	889230, 1287348, 1301024, 1317658
1274505	Remove support of SVG-based custom element	RESOLVED	mozilla50	FIXED	John Dai[:jdai]		889230, 1276579, 1396765
1275832	Implement custom element name validation for custom element	RESOLVED	mozilla52	FIXED	John Dai[:jdai]		889230, 1275835, 1275839
1275833	Add CustomElementsRegistry interface for custom element	RESOLVED	mozilla50	FIXED	John Dai[:jdai]	1289872	889230, 1275835, 1275838, 1275839
1275835	Implement CustomElementsRegistry define function	RESOLVED	mozilla51	FIXED	Edgar Chen [:edgar]	1275832, 1275833	889230, 1274159, 1275838, 1275839
1275838	Implement CustomElementsRegistry get function	RESOLVED	mozilla52	FIXED	John Dai[:jdai]	1275833, 1275835	889230
1275839	Implement CustomElementsRegistry whenDefined function	RESOLVED	mozilla52	FIXED	John Dai[:jdai]	1275832, 1275833, 1275835	889230
1276579	Revise document.createElement[NS] for custom elements	RESOLVED	mozilla50	FIXED	Jocelyn Liu [:jocelyn] [:joliu]	1274505, 1294100, 1318630, 1338889	889230, 1276240
1288306	Disable custom elements web-platform v0 tests	RESOLVED	mozilla50	FIXED	Edgar Chen [:edgar]		889230, 1396765
1294100	TypeError: Argument 2 of Document.createElement can't be converted to a dictionary.	VERIFIED	mozilla51	FIXED	John Dai[:jdai]		889230, 1276579
1309140	Rename CustomElementsRegistry to CustomElementRegistry	RESOLVED	mozilla52	FIXED	John Dai[:jdai]		889230
1341693	Crash [@mozilla::dom::WindowBinding::get_customElements]	RESOLVED	mozilla54	FIXED	Edgar Chen [:edgar]		1340565, 889230

12 Total; 0 Open (0%); 11 Resolved (91.67%); 1 Verified (8.33%);

1st Impl. Shipping Blocker: Stage_3 Bugs & Progress (DONE)

Full Query

ID	Summary	Status	Target milestone	Resolution	Assigned to	Depends on	Blocks
1121994	Implement adopted callback for custom elements	RESOLVED	mozilla58	FIXED	John Dai[:jdai]		889230, 1293921
1315885	Implement callback reaction for custom element reactions	RESOLVED	mozilla56	FIXED	John Dai[:jdai]	1309147, 1325279, 1347446	889230, 1293921, 1379573
1334043	Implement connected lifecycle callbacks for custom elements	RESOLVED	mozilla58	FIXED	Jessica Jong [:jessica] (inactive)		889230, 1293921, 1387125
1334044	Implement disconnected lifecycle callbacks for custom elements	RESOLVED	mozilla58	FIXED	Jessica Jong [:jessica] (inactive)		889230, 1293921
1334051	Implement list of observed attributes for custom elements' attributeChanged callbacks	RESOLVED	mozilla57	FIXED	Jessica Jong [:jessica] (inactive)		889230, 1293921
1340027	Add annotation with the [CEReactions] attribute	RESOLVED	mozilla56	FIXED	John Dai[:jdai]	1293921, 1309147	889230
1392970	Consider having a reference of the CustomElementDefinition in the custom element itself	RESOLVED	mozilla58	FIXED	Jessica Jong [:jessica] (inactive)		889230, 1396567, 1408828, 1410790

7 Total; 0 Open (0%); 7 Resolved (100%); 0 Verified (0%);