Say I have a DOM that looks like this in my Document:
<body>
<div id="outer">
<custom-web-component>
#shadow-root (open)
<div id="inner">Select Me</div>
</custom-web-component>
</div>
</body>
Is it possible to select the inner div inside the shadow root using a single querySelector argument on document? If so, how is it constructed?
For example, something like document.querySelector('custom-web-component > #inner')
You can do it like this:
document.querySelector("custom-web-component").shadowRoot.querySelector("#inner")
In short, not quite. The TL:DR is that, depending on how the component is set up, you might be able to do something like this:
document.querySelector('custom-web-component').div.innerHTML = 'Hello world!';
Do do this - if you have access to where the web component is created, you can add an interface there to access inner content. You can do this the same way you would make any JavaScript class variable/method public. Something like:
/**
* Example web component
*/
class MyComponent extends HTMLElement {
constructor() {
super();
// Create shadow DOM
this._shadowRoot = this.attachShadow({mode: 'open'});
// Create mock div - this will be directly accessible from outside the component
this.div = document.createElement('div');
// And this span will not
let span = document.createElement('span');
// Append div and span to shadowRoot
this._shadowRoot.appendChild(span);
this._shadowRoot.appendChild(this.div);
}
}
// Register component
window.customElements.define('custom-web-component', MyComponent);
// You can now access the component 'div' from outside of a web component, like so:
(function() {
let component = document.querySelector('custom-web-component');
// Edit div
component.div.innerHTML = 'EDITED';
// Edit span
component._shadowRoot.querySelector('span').innerHTML = 'EDITED 2';
})();
<custom-web-component></custom-web-component>
In this instance, you can access the div from outside of the component, but the span is not accessible.
To add: As web components are encapsulated, I don't think you can otherwise select internal parts of the component - you have to explicitly set a way of selecting them using this, as above.
EDIT:
Saying that, if you know what the shadow root key is, you can do this: component._shadowRoot.querySelector() (added to demo above). But then that is quite a weird thing to do, as it sorta goes against the idea of encapsulation.
EDIT 2
The above method will only work is the shadow root is set using the this keyword. If the shadow root is set as let shadowRoot = this.attachShadow({mode: 'open'}) then I don't think you will be able to search for the span - may be wrong there though.
This code will behave like query selector and work on nested shadowDoms:
const querySelectorAll = (node,selector) => {
const nodes = [...node.querySelectorAll(selector)],
nodeIterator = document.createNodeIterator(node, Node.ELEMENT_NODE);
let currentNode;
while (currentNode = nodeIterator.nextNode()) {
if(currentNode.shadowRoot) {
nodes.push(...querySelectorAll(currentNode.shadowRoot,selector));
}
}
return nodes;
}
Related
Context
I am building a React app (rails-react) where I have a parent component GameTracker that has some child components; namely, EquipmentPanel and PinnedPanels. I have added a pinned-panels-container div in the parent component where I want to move panels from the EquipmentPanel when I click on a 'pin' button.
<div id='container'>
<EquipmentPanel pinPanel={this.pinPanel}/>
<div id='tracker-contents'>
{this.state.pinnedPanels.length > 0 &&
<div id='pinned-panels-container'>
<h2>Pinned Panels</h2>
{this.state.pinnedPanels}
</div>}
</div>
</div>
Approach
The way I plan to do this is create a pinPanel() function in the parent component GameTracker, and pass it as a prop to its child, EquipmentPanel. The child then adds the button, and calls pinPanel(div), with div being the specific div/panel I want to pin.
pinPanel(panel) {
let newPanel = panel.current.cloneNode(true)
var parser = new DOMParser();
var htmlDoc = parser.parseFromString(newPanel.innerHTML, 'text/html');
newPanel = htmlDoc
let newPinnedPanels = this.state.pinnedPanels
newPinnedPanels.push(newPanel)
this.setState({
pinnedPanels: newPinnedPanels
})
}
Error
Now, whenever I pin a panel, React gives me:
Uncaught Error: Objects are not valid as a React child (found: [object HTMLDocument]).
If you meant to render a collection of children, use an array instead.
If I try to use an array, as the error message recommends, I get the same error. If I don't use DOMParser(), (which I found here), I get the same error, with the following difference: found: [object HTMLDivElement].
My question is, is there any way in React to clone a div with all its contents, pass it to another component through state, and render it in another component that is not its parent or child? I basically want to copy/paste a div.
Edit: If I try to assign it by .innerHTML, the end result is a panel with [object HTMLDocument] as a string inside.
Unsure if this is considered a proper answer, but I made it work with DOM manipulation. Feels hacky, but it works. If someone has any insight, it is of course welcome.
let newPanel = panel.current.cloneNode(true)
if (this.pinnedPanelsRef.current.innerHTML.includes(newPanel.children[0].innerHTML)) {
this.pinnedPanelsRef.current.innerHTML = this.pinnedPanelsRef.current.innerHTML.replace(newPanel.children[0].innerHTML, "")
}
else {
this.pinnedPanelsRef.current.innerHTML += newPanel.children[0].innerHTML
}
I still feel like there is a much more elegant solution that I am failing to reach.
I am trying to render polymer template using below code,
const shadowRoot = this.attachShadow({mode: 'open'});
const htmlTemplate = importDoc.querySelector('template');
shadowRoot.innerHTML = htmlTemplate.innerHTML;
But this renders two way binded data also as a string instead of showing the binded value e.g
<h1 id ="contactFooter">{{localize('_testVal')}}</h1>
is displayed as it is do anyone have any idea? Two way binding is just example it renders everything like this.
To use a <template> tag you should use importNode on the content.
e.g.
var clone = document.importNode(htmlTemplate.content, true);
shadowRoot.appendChild(clone);
// note that you will need to clear the shadowRoot if you do rerenderings
// OR you could try
shadowRoot.innerHTML = htmlTemplate.content;
see more details here https://developer.mozilla.org/en-US/docs/Web/HTML/Element/template
My function isn't called when I click the <a... tag.
I have the following code in my component:
public htmlstr: string;
public idUser:number;
this.idUser = 1;
this.htmlstr = `<a (click)="delete(idUser)">${idUser}</a>`;
public delete(idUser){
alert("id " + idUser);
}
My html
<div [innerHTML]="htmlstr"></div>
but the function delete isn't called and does not show the alert.
The <div... is created dynamically
If anyone face same issue and above all answer not working then try my trick :
In HTML :
<button onclick="Window.myComponent.test()"> test </button>
In component :
class
constructor(){
Window["myComponent"] = this;
}
test(){
console.log("testing");
}
Your main issue here, on-top of the things pointed out by #Matt Clyde and #Marciej21592, is that you're trying to dynamically add HTML code that needs to be compiled before it can be used (you're trying to bind to a method and variable).
Some ways of doing this can be seen here.
From the code you have supplied, however, there are much easier ways to accomplish what you are after. For starters, I would have that code in the HTML to begin with and hide/show it as needed with ngIf.
i use this method and its work
public htmlstr: string;
public idUser:number;
this.idUser = 1;
this.htmlstr = `<a id='innerHtmlClick'>${idUser}</a>`
this.htmlstr.querySelector(`innerHtmlClick`).addEventListener('click', () => {
this.delete(idUser);
});
public delete(idUser){
alert("id " + idUser);
}
EventListener listen the event bye using id of innerHtml
I assume that it is not a bug but rather Angular's security measure against XSS attacks - for more information I would suggest taking a look here https://angular.io/guide/security#sanitization-example
I somewhat also fail to understand why you insist on passing the event via string literal instead of just simply using:
<div>
<a (click)="delete(idUser)">${this.idUser}</a>
</div>
Your component has inner Html.
Angular will not allow events inside inner Html portions for security reasons. You can use Child components. to make events from inside of inner Html portions. Create a child component and put your html inside the child component and pass the data by using any angular events between parent and child using Input, Output features in Angular
I don't often use [innerHTML], but it looks like the template string you're using <a (click)="delete(idUser)">${idUser}</a> is referencing ${idUser} when you might have meant ${this.idUser}?
Below code snippet worked for me:-
In component :
ngAfterViewChecked () {
if (this.elementRef.nativeElement.querySelector('ID or Class of the Html element')) {
this.elementRef.nativeElement.querySelector('ID or Class of the Html element').addEventListener('click', this.editToken.bind(this));
}
}
inside constructor parameter:-
constructor( private readonly elementRef: ElementRef) {}
import { ElementRef } from '#angular/core';---> at the top of the file
implement 'AfterViewChecked'
I'm trying to implement a custom directive in Angular 2 for moving an arbitrary HTML element around. So far everything is working except that I don't now how to get the initial position of the HTML element when I click on it and want to start moving. I'm binding to the top and left styles of my HTML element with those two host bindings:
/** current Y position of the native element. */
#HostBinding('style.top.px') public positionTop: number;
/** current X position of the native element. */
#HostBinding('style.left.px') protected positionLeft: number;
The problem is that both of them are undefined at the beginning. I can only update the values which will also update the HTML element but I cannot read it? Is that suppose to be that way? And if yes what alternative do I have to retrieve the current position of the HTML element.
<div (click)="move()">xxx</div>
// get the host element
constructor(elRef:ElementRef) {}
move(ref: ElementRef) {
console.log(this.elRef.nativeElement.offsetLeft);
}
See also https://stackoverflow.com/a/39149560/217408
In typeScript you can get the position as follows:
#ViewChild('ElementRefName') element: ElementRef;
const {x, y} = this.element.nativeElement.getBoundingClientRect();
in html:
<div (click)="getPosition($event)">xxx</div>
in typescript:
getPosition(event){
let offsetLeft = 0;
let offsetTop = 0;
let el = event.srcElement;
while(el){
offsetLeft += el.offsetLeft;
offsetTop += el.offsetTop;
el = el.parentElement;
}
return { offsetTop:offsetTop , offsetLeft:offsetLeft }
}
My final objective is don't have to write HTML like this:
<div id='counter'>
{{counter}}
</div>
<div>
<button
id="startButton"
on-click="{{start}}">
Start
</button>
<button
id="stopButton"
on-click="{{stop}}">
Stop
</button>
<button
id="resetButton"
on-click="{{reset}}">
Reset
</button>
</div>
I would like to know if it is possible to create a Polymer-element without using HTML. For example I tried this:
#CustomTag('tute-stopwatch')
class TuteStopWatch extends PolymerElement {
ButtonElement startButton,
stopButton,
resetButton;
#observable String counter = '00:00';
TuteStopWatch.created() : super.created() {
createShadowRoot()..children = [
new DivElement()..text = '{{counter}}',
new DivElement()..children = [
startButton = new ButtonElement()..text = 'Start'
..onClick.listen(start),
stopButton = new ButtonElement()..text = 'Stop'
..onClick.listen(stop),
resetButton = new ButtonElement()..text = 'Reset'
..onClick.listen(reset)
]
];
}
}
Previous code creates HTML and shadow root correctly, but it doesn't create the binding between the #observable counter and the text of the DivElement.
I know that this is caused because I am trying to create the shadow root after the element has been instantiated/created. So that I should create the template of the element in other place before the template has been bound with its observable.
You can write a manual data binding like this:
changes.listen((changes) {
for (var change in changes) {
if (change.name == #counter) {
myDivElement.text = change.newValue;
}
}
});
changes is a property of the Observable class, which PolymerElement mixes in. (This is difficult to see in the API reference, as it currently doesn't show a class' mixins or the mixed in properties and methods.)
Polymer seems to be mostly about enabling declarative html based bindings. It may be worth exploring using custom elements and shadow dom directly, as you're not really using polymer for anything in this example. To do this you need to change the class definition to:
class TuteStopWatch extends HtmlElement with Observable {
...
}
And register your element with document.register(). You also need to include the polymer.js polyfill for custom elements.