Erik Arvidsson arv

Register

When called, the register method must run these steps:

Input

ENVIRONMENT, the unit of related similar-origin browsing contexts
DOCUMENT, the context object of the method
NAME, the custom element name of the element being registered
FUNCTION, the custom element constructor function, optional

class B {
  constructor(x) {
    this.x = x;
  }
  static [Symbol.create]() {
    var o = super();
    weakMap.set(o, 123456789);  // Dom wrapper foo
    return o;
 }

13.10.4 Runtime Semantics: Evaluation

WithStatement : with ( Expression ) Statement

Let val be the result of evaluating Expression.
Let obj be ToObject(GetValue(val)).
ReturnIfAbrupt(obj).
Let oldEnv be the running execution context’s LexicalEnvironment.
Let newEnv be NewObjectEnvironment(obj, oldEnv).

At the July TC39 meeting we decided to explore removing @@create in favor of a model where super() in a [[Construct]] call creates the instance object. To correctly know how to create the instance and set the prototype a [[Construct]] call gets an implicit receiver which is the constructor function new was called with.

class Base {
  constructor() {
    var object = Object.create(new*.prototype);  // new binding needs new syntax...
                                                 // bikeshed...
    myWeakMap.set(object, myHiddenData);
    return object;
 }

	// XXX should be standard (and named clone, after Java?)
	Object.prototype.copy = function () {
	let o = {}
	for (let i in this)
	o[i] = this[i]
	return o
	}

	// Containment testing for arrays and strings that should be coherent with their iterator.
	Array.prototype.contains = String.prototype.contains = function (e) {

	<!DOCTYPE html>
	<html>
	<head>
	<script src="../polymer/polymer.js"></script>
	</head>
	<body>
	<template id="host-template">
	<div>host shadowRoot</div>
	<content></content>
	</template>

	(function() {
	'use strict';

	function uncurryThis(f) {
	return f.call.bind(f);
	}

	var ShadowRoot = window.ShadowRoot;
	var createShadowRoot = uncurryThis(Element.prototype.createShadowRoot);
	var ownerDocumentGetter = uncurryThis(Object.getOwnPropertyDescriptor(Node.prototype, 'ownerDocument').get);

	if (!Document.prototype.createAttributeNS) {
	Document.prototype.createAttributeNS = function(namespaceURI, qualifiedName) {
	var dummy = this.createElement('dummy');
	dummy.setAttributeNS(namespaceURI, qualifiedName, '');
	var attr = dummy.attributes[0];
	dummy.removeAttributeNode(attr);
	return attr;
	};
	}

	<link rel="import" href="../core-scaffold/core-scaffold.html">
	<link rel="import" href="../core-header-panel/core-header-panel.html">
	<link rel="import" href="../core-menu/core-menu.html">
	<link rel="import" href="../core-item/core-item.html">
	<link rel="import" href="../core-icon-button/core-icon-button.html">
	<link rel="import" href="../core-toolbar/core-toolbar.html">
	<link rel="import" href="../core-menu/core-submenu.html">
	<link rel="import" href="../google-map/google-map.html">

	<polymer-element name="my-element">

	// Use Gists to store code you would like to remember later on
	console.log(window); // log the "window" object to the console