ES2015 / JS6 中的自定义元素

Question

什么是 ES205 / JS6 方式，使自定义元素等同于 this DartLang 制作的自定义元素

Answer 1

我做到了，下面是我为有兴趣的人做的：

       "use strict";

   // DART: class SaveBtn extends HtmlElement { static final tag = 'save-button';
   // ES2015 / JS6
   class SaveBtn extends HTMLElement {

   // DART: factory SaveBtn([String name]) => (new Element.tag(tag) as SaveBtn)..name = name;
   // ES2015 / JS6 
   constructor() {
       super();    
    }

    // DART:  SaveBtn.created() : super.created() {
    // ES2015 / JS6   
    createdCallback(){
        //  Create a Shadow Root, DART & ES2015
        var shadow = this.createShadowRoot();
        // Create a standard element and set it's attributes.
        // DART: innerButton = new ButtonElement()..id='btn';
        // ES2015 / JS6
        var innerButton = document.createElement('button');
        innerButton.id='btn';

        innerButton.addEventListener('click',() => console.log('The button had been clicked'));
        shadow.appendChild(innerButton); 
     }

     // DART: void attached() { }
     // ES2015 / JS6
     attachedCallback(){
         console.log(this.dataset);
         console.log(this.textContent);
          this.shadowRoot.querySelector('#btn').textContent = this.textContent != '' ? this.textContent : this.dataset['text'];
      }

      detachedCallback(){

       }

        attributeChangedCallback(textContent) {

        }

        set text(v) {
            this.textContent = v;
        }

        get text() {
             return this.textContent;
        } 
    }

     var MySaveBtn = document.registerElement("save-button", SaveBtn);
     var x = new MySaveBtn;
     x.text = 'test';
     console.log(x.text);
     document.querySelector('#placeholder').appendChild(x);

我使用的 HTML 文件是：

  <!doctype html>
  <html lang="en">
  <head>
     <meta charset="UTF-8">
     <title>ES2015 / JS6 Custom Elements</title>
     <script src="default.js" type="text/javascript"></script>
  </head>
  <body>

  Here is some non-custom stuff.

  <div id="placeholder"><p>Please wait, loading cool things<p></div>

  <save-button data-text='click this'></save-button>
  </body>

  </html>

另一种不使用 SHADOWROOT 的解决方法是 here

ES2015 / JS6 中的自定义元素

Custom Elements in ES2015 / JS6

javascript

custom-element