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Dom Insertion (of Scripts and Styles)

You can use the DomInsertionService in @abp/ng.core package in order to insert scripts and styles in an easy and explicit way.

Getting Started

You do not have to provide the DomInsertionService at module or component level, because it is already provided in root. You can inject and start using it immediately in your components, directives, or services.

import { DomInsertionService } from '@abp/ng.core';

@Component({
  /* class metadata here */
})
class DemoComponent {
  constructor(private domInsertionService: DomInsertionService) {}
}

Usage

You can use the insertContent method of DomInsertionService to create a <script> or <style> element with given content in the DOM at the desired position. There is also the projectContent method for dynamically rendering components and templates.

How to Insert Scripts

The first parameter of insertContent method expects a ContentStrategy. If you pass a ScriptContentStrategy instance, the DomInsertionService will create a <script> element with given content and place it in the designated DOM position.

import { DomInsertionService, CONTENT_STRATEGY } from '@abp/ng.core';

@Component({
  /* class metadata here */
})
class DemoComponent {
  constructor(private domInsertionService: DomInsertionService) {}

  ngOnInit() {
    const scriptElement = this.domInsertionService.insertContent(
      CONTENT_STRATEGY.AppendScriptToBody('alert()')
    );
  }
}

In the example above, <script>alert()</script> element will place at the end of <body> and scriptElement will be an HTMLScriptElement.

Please refer to ContentStrategy to see all available content strategies and how you can build your own content strategy.

Important Note: DomInsertionService does not insert the same content twice. In order to add a content again, you first should remove the old content using removeContent method.

How to Insert Styles

If you pass a StyleContentStrategy instance as the first parameter of insertContent method, the DomInsertionService will create a <style> element with given content and place it in the designated DOM position.

import { DomInsertionService, CONTENT_STRATEGY } from '@abp/ng.core';

@Component({
  /* class metadata here */
})
class DemoComponent {
  constructor(private domInsertionService: DomInsertionService) {}

  ngOnInit() {
    const styleElement = this.domInsertionService.insertContent(
      CONTENT_STRATEGY.AppendStyleToHead('body {margin: 0;}')
    );
  }
}

In the example above, <style>body {margin: 0;}</style> element will place at the end of <head> and styleElement will be an HTMLStyleElement.

Please refer to ContentStrategy to see all available content strategies and how you can build your own content strategy.

Important Note: DomInsertionService does not insert the same content twice. In order to add a content again, you first should remove the old content using removeContent method.

How to Remove Inserted Scripts & Styles

If you pass the inserted HTMLScriptElement or HTMLStyleElement element as the first parameter of removeContent method, the DomInsertionService will remove the given element.

import { DomInsertionService, CONTENT_STRATEGY } from '@abp/ng.core';

@Component({
  /* class metadata here */
})
class DemoComponent {
  private styleElement: HTMLStyleElement;

  constructor(private domInsertionService: DomInsertionService) {}

  ngOnInit() {
    this.styleElement = this.domInsertionService.insertContent(
      CONTENT_STRATEGY.AppendStyleToHead('body {margin: 0;}')
    );
  }

  ngOnDestroy() {
    this.domInsertionService.removeContent(this.styleElement);
  }
}

In the example above, <style>body {margin: 0;}</style> element will be removed from <head> when the component is destroyed.

API

insertContent

insertContent<T extends HTMLScriptElement | HTMLStyleElement>(
  contentStrategy: ContentStrategy<T>,
): T

contentStrategy parameter is the primary focus here and is explained above.
returns HTMLScriptElement or HTMLStyleElement based on given strategy.

removeContent

removeContent(element: HTMLScriptElement | HTMLStyleElement): void

element parameter is the inserted HTMLScriptElement or HTMLStyleElement element, which was returned by insertContent method.

has

has(content: string): boolean

The has method returns a boolean value that indicates the given content has already been added to the DOM or not.

content parameter is the content of the inserted HTMLScriptElement or HTMLStyleElement element.

What's Next?

ContentProjectionService

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