克隆聚合物元素的正确方法是什么? [英] What is the correct way to clone a polymer element?
问题描述
我一直在尝试克隆聚合物元素 - 通常是从某种数据创建的元素，因此仅使用构造函数或 document.createElement<创建模板的新实例不是一种选择/代码>.
element.cloneNode不能单独工作，因为它不复制影子根lodash由 Polymer Clone Objects 提出似乎没有任何作用(克隆对象为空)cloneEl.shadowRoot.innerHTML = sourceEl.shadowRoot.innerHTML;复制了 shadow-root，但似乎失去了绑定
广泛的例子:http://jsbin.com/vitumuwayu/3/edit
是否有我找不到的 Polymer.cloneNode 函数?
我终于找到了这个问题的答案(至少对于 Polymer 1.0).
https://stackoverflow.com/a/6620327/1878199 展示了如何复制属性.https://stackoverflow.com/a/25187164/1878199 描述了如何获取聚合物元素的属性列表.
答案是:
newElement = element.cloneNode(true);for(var i in element.properties) {newElement[i] = 元素[i]}完整说明和工作示例 在 jsbin 上 或在下面的代码段中.
<头><link rel="import" href="https://cdn.rawgit.com/download/polymer-cdn/1.0.1/lib/polymer/polymer.html"><meta charset="utf-8"><title>聚合物克隆实施例</title><dom-module id="自定义元素"><模板><div style="border:solid"><input type="text" name="some_string" value="{{boundvalue::input}}"><p>{{boundvalue}}</p><脚本>聚合物({是:'自定义元素'，特性: {边界值:{类型:字符串，value: '输入一些文字...',通知:真实}}});</dom-module><身体><custom-element id="source-element"></custom-element><p><button onclick="cloneElementWithoutProperties()">1 将上面的元素克隆到下面的列表中</button><p></p><button onclick="cloneElementWithProperties()">2 将上面的元素克隆到下面的列表中并复制属性</button><p></p><h3>测试描述</h3><ol><li>修改上面的文字</li><li>点击按钮 1</li><p></p><p>Observed:下面添加了一个元素，但它被重置为原始文本('输入一些文本...')</p><li>点击按钮 2</li><p></p><p>Observed:下面添加了一个元素，并保留了修改后的文本</p><p>同时验证功能是否还可以:修改副本中的输入，文本也更新了</p></ol><h3>克隆元素列表:</h3><div id='list-elements'>
</html><脚本>函数 cloneElementWithProperties() {list = document.querySelector("#list-elements");sourceEl = document.querySelector("#source-element")cloneEl = sourceEl.cloneNode(true);for (var i in sourceEl.properties) {cloneEl[i] = sourceEl[i];}list.insertBefore(cloneEl, null);}函数 cloneElementWithoutProperties() {list = document.querySelector("#list-elements");sourceEl = document.querySelector("#source-element")cloneEl = sourceEl.cloneNode(true);list.insertBefore(cloneEl, null);}</script>
I have been trying to clone polymer elements - typically elements that have been created from data of some kind, so it is not an option to just create a new instance of the template with the constructor or document.createElement.
element.cloneNodedoes not work on its own as it does not copy the shadow-rootlodashproposed by Polymer Clone Objects does not seem to do anything (cloned object is empty)cloneEl.shadowRoot.innerHTML = sourceEl.shadowRoot.innerHTML;copies the shadow-root, but seems to lose the binding
Extensive example: http://jsbin.com/vitumuwayu/3/edit
Is there a Polymer.cloneNode function I have been unable to find?
I have finally found an answer to this question (at least for Polymer 1.0).
https://stackoverflow.com/a/6620327/1878199 shows how to copy properties. https://stackoverflow.com/a/25187164/1878199 describes how to get the list of properties for a polymer element.
The answer is then:
newElement = element.cloneNode(true);
for(var i in element.properties) {
newElement[i] = element[i]
}
Full illustrated and working example on jsbin or in the snippet below.
<!DOCTYPE html>
<html>
<head>
<link rel="import" href="https://cdn.rawgit.com/download/polymer-cdn/1.0.1/lib/polymer/polymer.html">
<meta charset="utf-8">
<title>Polymer Cloning Example</title>
</head>
<dom-module id="custom-element">
<template>
<div style="border: solid">
<input type="text" name="some_string" value="{{boundvalue::input}}">
<p>{{boundvalue}}</p>
</div>
</template>
<script>
Polymer({
is: 'custom-element',
properties: {
boundvalue: {
type: String,
value: 'Enter some text...',
notify: true
}
}
});
</script>
</dom-module>
<body>
<custom-element id="source-element"></custom-element>
<p>
<button onclick="cloneElementWithoutProperties()">1 Clone the above element into the list below</button>
<p></p>
<button onclick="cloneElementWithProperties()">2 Clone the above element into the list below and also copy properties</button>
<p></p>
<h3>Test Description</h3>
<ol>
<li>Modify text above</li>
<li>Click Button 1</li>
<p></p>
<p>Observed: An element is added below, but it is reset to the original text ('Enter some text...')</p>
<li>Click Button 2</li>
<p></p>
<p>Observed: An element is added below, and it keeps the modified text</p>
<p>Also verify that the functionality is still ok: Modify the input in the copy, the text is also updated</p>
</ol>
<h3>List of cloned elements:</h3>
<div id='list-elements'>
</div>
</body>
</html>
<script>
function cloneElementWithProperties() {
list = document.querySelector("#list-elements");
sourceEl = document.querySelector("#source-element")
cloneEl = sourceEl.cloneNode(true);
for (var i in sourceEl.properties) {
cloneEl[i] = sourceEl[i];
}
list.insertBefore(cloneEl, null);
}
function cloneElementWithoutProperties() {
list = document.querySelector("#list-elements");
sourceEl = document.querySelector("#source-element")
cloneEl = sourceEl.cloneNode(true);
list.insertBefore(cloneEl, null);
}
</script>
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