Polymorpheus is a tiny library for polymorphic templates in Angular.
It is 1 KB gzip, dependency free and allows you to make pretty cool things.
It abstracts over different ways of view customization in Angular with one simple structural directive:
<ng-container *polymorpheusOutlet="content as text; context: context">
{{text}}
</ng-container>
Content accepts:
- primitives like
number
orstring
- functions that take
context
as argument and return a primitive - templates that get instantiated with given
context
- components that would get
context
injected through DI
Context is optional when you need your content to adapt to the situation
Typical use case would be a component that accepts visual customization and defines context by itself. Say a menu list where you can configure how each item should look like by passing a template. And context would be item itself and, for example, whether it is focused or not.
Please see extensive demo (wait for packages to install and run npm start
).
You can also read about this concept in detail.
If you use component content you can inject context with POLYMORPHEUS_CONTEXT
token.
Important! This object is live so if you change it, your component will not be recreated:
@Component({
template: '{{context.active}}`, // <-- this will automatically update
changeDetection: ChangeDetectionStrategy.OnPush,
})
export class MyComponent {
constructor(
@Inject(POLYMORPHEUS_CONTEXT) readonly context: { active: boolean }
) {}
}
You can use polymorpehus
directive to add type to template context:
readonly context!: { $implicit: number };
<ng-template #template="polymorpheus" [polymorpheus]="context" let-item>
{{ item.toFixed(2) }} <-- type 'number'
</ng-template>
Do you also want to open-source something, but hate the collateral work? Check out this Angular Open-source Library Starter we’ve created for our projects. It got you covered on continuous integration, pre-commit checks, linting, versioning + changelog, code coverage and all that jazz.
![]() Alex Inkin |
![]() Roman Sedov |