in Polymer 0.5 it was possible to set an element on an element via something like
scrollTarget="{{$.scroller}}"
Is this possible with 1.0? There is a element-property (positionTarget) for example in iron-dropdown. But I do not find an example for that..
Kind regards!
You could do it imperatively:
this.$.myDropdown.positionTarget = this.$.targetElement;
or you could do it partially declaratively:
positionTarget="[[getElement('targetElement')]]"
where getElement is defined as:
getElement: function(element) {
return this.$[element];
}
As far as I know, this is no longer possible. If you look at the migration guide, it describes that binding to sibling properties is not supported anymore. While you are not trying to bind a property, but to the element itself, you require the same syntax with the $ sign, which appears to have been removed.
Related
The component that I have testing renders something this:
<div>Text<span>span text</span></div>
As it turns out for testing the only reliable text that I have is the 'span text' but I want to get the 'Text' part of the <div>. Using Jest and react-testing-library I can
await screen.findByText(spanText)
This returns an HTMLElement but it seems limited as I don't have any of the context around the element. For example HTML methods like parentNode and previousSibling return null or undefined. Ideally I would like to get the text content of the parent <div>. Any idea how I can do this with either Jest or react-testing-library?
A good solution for this is the closest function.
In description of closest function is written: Returns the first (starting at element) including ancestor that matches selectors, and null otherwise.
The solution would look like this:
screen.getByText("span text").closest("div")
Admittedly, Testing Library doesn't communicate clearly how to do this. It includes an eslint rule no-direct-node-access that says "Avoid direct Node access. Prefer using the methods from Testing Library". This gives the impression that TL exposes a method for a situation like this, but at the moment it does not.
It could be you don't want to use .closest(), either because your project enforces that eslint rule, or because it is not always a reliable selector. I've found two alternative ways to tackle a situation like you describe.
within():
If your element is inside another element that is selectable by a Testing Library method (like a footer or an element with unique text), you can use within() like:
within(screen.getByRole('footer')).getByText('Text');
find() within the element with a custom function:
screen.getAllByText('Text').find(div => div.innerHTML.includes('span text'));
Doesn't look the prettiest, but you can pass any JS function you want so it's very flexible and controllable.
Ps. if you use my second option depending on your TypeScript config you may need to make an undefined check before asserting on the element with Testing Library's expect(...).toBeDefined().
But I have used HTML methods a lot and there was no problem yet. What was your problem with HTML methods?
You can try this code.
const spanElement = screen.getElementByText('span text');
const parentDiv = spanElement.parentElement as HTMLElement;
within(parentDiv).getElementByText('...');
I can not understand what it exactly does according to the documentation.
This documentation is not detailed enough.
Is there an example?
The documentation isn't that deep because what this does isn't that big of a deal, all that this decorator does is create a "shortcut" of sorts for calling querySelector on the element's root (be it this.shadowRoot if you're using shadow dom or this if you're not)
So basically this TS code:
#query('.someClass')
private _someClassElement: Element
is the same as doing this in JS
get _someClassElement() {
return this.shadowRoot.querySelector('.someClass');
// or this.querySelector('.someClass') if you're not using shadow dom
}
I got an error when i put a nested ng-show attributes for custom directive,
one attribute in the markup of the directive and the second inside the root element of the directive template.
My real scenario are complex so i will simplify it to this example:
Suppose i have my-custom-directive below which already contains ng-show:
<my-custom-directive ng-show="someValue >= 5"></my-custom-directive>
And then the template of 'my-custom-directive' look like this:
<div ng-show="options != null">My Custom Directive</div>
Those multiple ng-show together cause an error.
if i remove one of them or move the inner ng-show at least one level deeper in it's dom tree the error gone (it's happen when it's location is on the root template element).
this error tested on angular v1.4.8.
Is this angular bug? or there is a reasonable explanation for this behavior?
here is the Plunker example:
http://embed.plnkr.co/ZTZVcfc5bfmjPo9t0Isw
Thank you in advance,
Menachem
Because the directive has replace: trueit is trying to merge the two ng-show values together resulting in an error. The simplest solution I believe is to just do replace: false
Or you can inject the value via isolate scope and use a single ng-show value within the directive. I believe this is considered the cleaner solution.
Example: http://plnkr.co/edit/5oc8c1Hrz8N1F2klCio7?p=info
scope: {
someValue: '=someValue'
}
Please refer to this JSBin, basically I would like to create an instance of an element in its parent element scope. Wondering how should I do this?
If possible, is there a declarative way to do this?
Thanks.
PS. Please open the link in Chrome only.
There are several ways to instantiate and element.
Declarative:
<my-element>
JS:
document.createElement('my-element');
Constructor (if one is find):
new MyElement();
See http://www.html5rocks.com/en/tutorials/webcomponents/customelements/#instantiating
I believe you are looking for the constructor (see here) attribute.
You need to include it in your polymer element declaration.
<polymer-element name="p-paper"
attributes="content"
constructor="Paper"
noscript>
And then you can create instances of your element like this -
// How to create an instance of <p-paper> here?
var paper = new Paper();
To set the html of elements on my site, I use mostly
$('elementId').innerHTML = "<p>text</p>";
Looking through the mootools docs, I found this example given:
$('myElement').set('html', '<div></div><p></p>');
Is there any difference between these? Should I go through and change .innerHTML to the mootools method, or doesn't it make a difference?
the reason why the first one works is because - as it stands - a $ selector (document.id) in mootools returns the actual element. this - in normal browsers - is identical to document.getElementById() and the element object exposes any and all of its attributes/properties for you to edit.
the problems with NOT using .set are:
when mootools 2.0 aka MILK gets released, it won't work as it will be wrapped like jQuery and the selector won't return the object (mootools is becoming AMD hence it won't modify native Types - Element, Array, Number, String, Function(maybe!) - prototypes).
you cannot chain this. with set you can: $('someid').set("html", "loading...").highlight();, for example.
set is overloaded - it can set either a single property or multiples by means of passing an object. eg, element.set({html: "hello", href: "#", events: boundObj});
look at https://github.com/mootools/mootools-core/blob/master/Source/Element/Element.js#L936-942 - you can pass an array as an argument and it will join it for you, this makes it easy to work with multi-line strings and ensures performance in IE
edit: the BBT fan has kind of opened a separate topic: should the framework try to block you / prevent you from doing things that break the browser?
if you want to, you can add disallowed elements by changing that setter Element.Properties.html.set = function() { var tag = this.get("tag"); ... check tag }; - isn't mootools great?
mootools - by default - will NOT try to prevent you from doing stupid shit [tm] - that's your responsibility :) try setting height on an element to a negative value in IE, for example. should the Fx class prevent you from doing that? No. Should the setter prevent you? No. The footprint of constant checks to see if you are not breaking means it will slow everything down in performance-critical cases like animations.