Is there a name for a class that simply acts as a holder for mixins?
A simple example in C++ would look like this:
template<typename... Mixins>
class WhatsMyName : Mixins... {
};
WhatsMyName doesn't have any functionality of its own, and is just a proxy for the mixins that it contains.
Container and Holder seem too generic, MixingBowl is too cute, and Cone is too obscure. I'm stumped!
It's a Case, or Armor. Or if you want to be cute, a Katamari.
It's just a regular class. Mixins are an implementation detail and should have no effect on the naming. It should be named for what it does, not what it contains.
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('...');
is there a (good) way to mark a CSS class as deprecated?
The idea is during refactoring, when you create new clean classes, but want to update your site gradually so you have to keep both the old and new class for some time, but you would like other to only use the new class for new features.
A comment in the class definition is a first step, but only helps when you actually check the class implementation, it doesn't help when the class usage is just copied from somewhere else.
What I'm looking for is rather something that would be displayed in the IDE or where a linter could throw a warning
You can put messages inside your css rulesets like so:
.center {
text-align: "center";
--deprecated: "WARNING: Use .other-class instead";
}
This way developers and users can see the message directly in their browsers and take action
You can simply add comment to the old class (for example: /* duplicate, new class created*/, so that you know what to delete after you have new class.
I would like to check if a mixin has been applied to a custom element, but I don't think I can use 'instanceof', since a mixin is not properly a base class (I tried, of course).
I would need to enforce that an element added to a collection can be only of a kind with a particular class mixin applied...
Any suggestions?
Not sure I understand you question correctly.
I assume you want to check something like MyCustomElement has already apply MyMixin or not?
You can check from the instance
let instance = new MyCustomElement()
console.log(instance instanceof MyMixin)
This will only work when MyMixin is a class not a factory function. If you follow documentation you need to change it.
Another way, you can declare some static function in MyMixin. Then you can call from MyCustomElement to check it.
I want to make a setter for the fontSize property of my WrappedLabel class because I need to do some additional stuff when someone changes it.
So when someone uses my class like this:
<comp:WrappedLabel fontSize="10"/>
I want to know.
I tried to override setStyle but looks like it doesn't get called when fontSize is initialized in mxml.
That's actually easier to accomplish then you might think, but it involves metadata. All you need to do is add a Style metadata declaration to your class definition, like so:
[Style(name="fontSize", type="Number", inherit="no")]
public class WrappedLabel {
...
}
If you want more information on the parameters of the metadata, read the docs.
I previously asked about what Mixins were, and have begun to get the gist of what the pattern means. But it got me wondering if there is a common pattern name for doing something like Mixins at an Object level as opposed to the Class level.
Pseudo code (in some non existent language):
Class MyClass
{
function foo()
{
print("foo")
}
}
function bar()
{
print("bar")
}
object = MyClass.new()
object.xxxx(bar)
object.bar() #output: bar
I know stuff like this can be done in several languages, in one way or another, but I'm wondering what would be the "standard" name for the functionality xxxx represents, and what is the name for this pattern, if there is one.
Thanks!
Edit: Expanding on finnsson's answer I guess something like this might be another case of this would be:
object.xxxx(OtherClass)
object.otherfoo()
Would concatenate be appropriate?
Quote: "Concatenation: Under pure prototyping, which is also referred to as concatenative prototypes..." -wikipedia
This is common in prototype-based programming languages. I belive it's called "import" in ruby but it's some time since I last programmed ruby so I'm not sure.
In js/ruby you would write
object.bar = bar;
object.bar() // output: bar
and than it's no real pattern, since it's just an assignment (o.bar = bar) making perfect sense in a prototype-based language. I guess xxxx in your example could be called prototype or something similar (see http://en.wikipedia.org/wiki/Prototype-based_programming where a language calles this proto).